This comparison presents the key properties of unfilled PET in its amorphous and semi-crystalline forms. The table covers physical, mechanical, thermal, electrical, optical, processing, durability, environmental, and recycling-related properties.

Property	PET – Unfilled, Amorphous	PET – Unfilled, Semi-Crystalline
Designation	Polyethylene Terephthalate (unfilled, amorphous)	Polyethylene Terephthalate (unfilled, semi-crystalline)
Typical uses	Blow molded bottles, packaging film, film, photographic and x-ray film, audio/visual tapes, industrial strapping, capacitor film, drawing office transparencies, fibers.	Electrical fittings and connectors, audio/visual tapes, industrial strapping, capacitor film, fibers.
Compositional summary	(CO-(C6H4)-CO-O-(CH2)2-O)n	(CO-(C6H4)-CO-O-(CH2)2-O)n
Material family	Plastic (thermoplastic, amorphous)	Plastic (thermoplastic, semi-crystalline)
Base material	PET (Polyethylene terephthalate)	PET (Polyethylene terephthalate)
Polymer code	PET	PET
Polymer	100 %	100 %
Density	1.29 – 1.39 g/cm³	1.37 – 1.4 g/cm³
Young’s modulus	2.8 – 3 GPa	2.76 – 3.1 GPa
Specific stiffness	2.06 – 2.28 MN.m/kg	1.99 – 2.24 MN.m/kg
Yield strength (elastic limit)	50 – 55 MPa	65 – 70 MPa
Tensile strength	55 – 60 MPa	70 – 75 MPa
Specific strength	36.9 – 41.6 kN.m/kg	46.9 – 50.6 kN.m/kg
Elongation	280 – 320 % strain	65 – 75 % strain
Compressive modulus	2.76 – 4.14 GPa	2.76 – 4.14 GPa
Compressive strength	50 – 60 MPa	75.8 – 103 MPa
Flexural modulus	2.41 – 3.09 GPa	2.99 – 3.09 GPa
Flexural strength (modulus of rupture)	50 – 60 MPa	70 – 75 MPa
Shear modulus	0.994 – 1.49 GPa	0.994 – 1.49 GPa
Bulk modulus	4.94 – 5.19 GPa	4.94 – 5.19 GPa
Poisson’s ratio	0.381 – 0.396	0.381 – 0.396
Shape factor	5.6	4.9
Hardness – Vickers	2 – 5 HV	17 – 20 HV
Hardness – Rockwell M	28 – 30	82 – 87
Hardness – Rockwell R	45 – 50	120 – 125
Elastic stored energy (springs)	430 – 524 kJ/m³	709 – 853 kJ/m³
Fatigue strength at 10^7 cycles	19.3 – 29 MPa	19.3 – 29 MPa
Fracture toughness	4.75 – 5.25 MPa.m^0.5	4.75 – 5.25 MPa.m^0.5
Toughness (G)	7.76 – 9.54 kJ/m²	7.62 – 9.54 kJ/m²
Impact strength, notched 23 °C	6.19 – 6.83 kJ/m²	2.86 – 3.15 kJ/m²
Impact strength, unnotched 23 °C	590 – 600 kJ/m²	590 – 600 kJ/m²
Melting point	NA (Amorphous PET does not have a melting temperature because it lacks a long-range, ordered crystalline structure.)	255 – 265 °C
Glass temperature	60 – 84 °C	68 – 80 °C
Heat deflection temperature 0.45MPa	70 – 74 °C	105 – 115 °C
Heat deflection temperature 1.8MPa	68 – 72 °C	70 – 80 °C
Maximum service temperature	55 – 65 °C	115 – 120 °C
Minimum service temperature	-58 – -38 °C	-58 – -38 °C
Thermal conductivity	0.138 – 0.151 W/m.°C	0.138 – 0.151 W/m.°C
Specific heat capacity	1.15e3 – 1.25e3 J/kg.°C	1.1e3 – 1.2e3 J/kg.°C
Thermal expansion coefficient	115 – 119 µstrain/°C	75 – 80 µstrain/°C
Thermal shock resistance	145 – 164 °C	276 – 321 °C
Thermal distortion resistance	0.00117 – 0.0013 MW/m	0.00176 – 0.00197 MW/m
Electrical resistivity	3.3e20 – 3e21 µohm.cm	3.3e20 – 3e21 µohm.cm
Electrical conductivity	5.75e-20 – 5.22e-19 %IACS	5.75e-20 – 5.22e-19 %IACS
Dielectric constant (relative permittivity)	3.5 – 3.7	3.5 – 3.7
Dissipation factor (dielectric loss tangent)	0.003 – 0.007	0.002 – 0.003
Dielectric strength (dielectric breakdown)	36 – 44 MV/m	16.5 – 18 MV/m
Comparative tracking index	200 – 325 V	200 – 325 V
Magnetic type	Non-magnetic	Non-magnetic
Refractive index	1.57 – 1.58	1.57 – 1.58
Transparency	Optical quality	Opaque
Acoustic velocity	1.43e3 – 1.51e3 m/s	1.41e3 – 1.5e3 m/s
Mechanical loss coefficient (tan delta)	0.00966 – 0.0145	0.00966 – 0.0145
Contains >5wt% critical elements?	No	No
Water absorption @ 24 hrs	0.14 – 0.18 %	0.1 – 0.2 %
Water vapor transmission	0.464 – 0.707 g.mm/m².day	0.464 – 0.707 g.mm/m².day
Permeability (O2)	1.2 – 2.77 cm³.mm/m².day.atm	1.2 – 2.77 cm³.mm/m².day.atm
Polymer injection molding	Acceptable	Acceptable
Polymer extrusion	Limited use	Limited use
Polymer thermoforming	Acceptable	Limited use
Linear mold shrinkage	0.3 – 0.5 %	1.5 – 1.7 %
Melt temperature	260 – 280 °C	260 – 280 °C
Mold temperature	20 – 30 °C	125 – 145 °C
Molding pressure range	13.8 – 48.1 MPa	13.8 – 48.1 MPa
Water (fresh)	Excellent	Excellent
Water (salt)	Excellent	Excellent
Weak acids	Acceptable	Acceptable
Strong acids	Unacceptable	Unacceptable
Weak alkalis	Acceptable	Acceptable
Strong alkalis	Limited use	Limited use
Organic solvents	Limited use	Limited use
Oxidation at 500C	Unacceptable	Unacceptable
UV radiation (sunlight)	Fair	Fair
Flammability	Highly flammable	Highly flammable
Embodied energy, primary production	78.4 – 86.4 MJ/kg	78.4 – 86.4 MJ/kg
CO2 footprint, primary production	2.59 – 2.86 kg/kg	2.59 – 2.86 kg/kg
Water usage	126 – 140 l/kg	126 – 140 l/kg
Polymer extrusion energy	5.82 – 6.43 MJ/kg	5.8 – 6.42 MJ/kg
Polymer extrusion CO2	0.437 – 0.483 kg/kg	0.435 – 0.481 kg/kg
Polymer extrusion water	4.83 – 7.24 l/kg	4.82 – 7.23 l/kg
Polymer molding energy	18.7 – 20.6 MJ/kg	18.2 – 20.1 MJ/kg
Polymer molding CO2	1.4 – 1.55 kg/kg	1.36 – 1.51 kg/kg
Polymer molding water	12.6 – 18.9 l/kg	12.4 – 18.6 l/kg
Coarse machining energy	0.864 – 0.954 MJ/kg	1.08 – 1.19 MJ/kg
Coarse machining CO2	0.0648 – 0.0716 kg/kg	0.0811 – 0.0896 kg/kg
Fine machining energy	4.36 – 4.82 MJ/kg	6.54 – 7.22 MJ/kg
Fine machining CO2	0.327 – 0.361 kg/kg	0.49 – 0.542 kg/kg
Grinding energy	8.25 – 9.11 MJ/kg	12.6 – 13.9 MJ/kg
Grinding CO2	0.618 – 0.684 kg/kg	0.945 – 1.04 kg/kg
Embodied energy, recycling	26.8 – 29.6 MJ/kg	26.8 – 29.6 MJ/kg
CO2 footprint, recycling	1.45 – 1.6 kg/kg	1.45 – 1.6 kg/kg
Recycle fraction in current supply	20 – 22.1 %	20 – 22.1 %
Heat of combustion (net)	23 – 24.2 MJ/kg	23 – 24.2 MJ/kg
Combustion CO2	2.24 – 2.35 kg/kg	2.24 – 2.35 kg/kg

Polycarbonate (PC) is supplied in both high- and low-viscosity molding and extrusion grades, both based on the same bisphenol-A (BPA) homopolymer chemistry. The two grades share identical density, pricing, and the great majority of mechanical, thermal, electrical, and environmental properties – differing chiefly in molecular weight. The high-viscosity grade’s higher molecular weight gives it markedly greater impact toughness (up to roughly three times higher in unnotched impact strength) and a modest edge in heat deflection and maximum service temperature, but it is harder to process, requiring higher melt temperatures and molding pressures. The low-viscosity grade trades some of that toughness for easier processability, slightly better elongation at break, and marginally lower processing energy and emissions. The table below sets the full property sets of both grades side by side, with the properties that actually differ between them highlighted for quick reference.

Property	PC High Viscosity	PC Low Viscosity	Unit	Difference
General Information
Designation	High Viscosity, Unfilled, Molding and Extrusion	Low Viscosity, Unfilled, Molding and Extrusion	—	Grade designation differs
Compositional note	Higher molecular weight; less processable but more tough	Lower molecular weight; more processable but less tough	—	High-visc = tougher/less processable; Low-visc = more processable/less tough
Material family	Plastic (thermoplastic, amorphous)	Plastic (thermoplastic, amorphous)	—	Identical
Base material	PC (Polycarbonate)	PC (Polycarbonate)	—	Identical
Polymer code	PC	PC	—	Identical
Polymer content	100	100	%	Identical
Physical Properties
Density	1.19 – 1.21	1.19 – 1.21	g/cm³	Identical
Mechanical Properties
Young’s modulus	2.32 – 2.44	2.32 – 2.44	GPa	Identical
Specific stiffness	1.93 – 2.04	1.93 – 2.04	MN.m/kg	Identical
Yield strength (elastic limit)	59.1 – 65.2	59.1 – 65.2	MPa	Identical
Tensile strength	62.7 – 72.4	62.7 – 72.4	MPa	Identical
Specific strength	49.2 – 54.4	49.2 – 54.4	kN.m/kg	Identical
Elongation	110 – 120	110 – 150	% strain	Low visc. has higher max elongation (up to 150 vs 120)
Compressive modulus	2.35 – 2.47	2.35 – 2.47	GPa	Identical
Compressive strength	69 – 86.2	69 – 86.2	MPa	Identical
Flexural modulus	2.27 – 2.34	2.27 – 2.34	GPa	Identical
Flexural strength (modulus of rupture)	86.2 – 93.1	82.7 – 96.5	MPa	Low visc. range is wider (lower min, higher max)
Shear modulus	0.829 – 0.872	0.829 – 0.872	GPa	Identical
Bulk modulus	3.83 – 4.03	3.83 – 4.03	GPa	Identical
Poisson’s ratio	0.391 – 0.407	0.391 – 0.407	—	Identical
Shape factor	4.6	4.6	—	Identical
Hardness – Vickers	18 – 20	18 – 20	HV	Identical
Hardness – Rockwell M	70 – 75	70 – 75	—	Identical
Hardness – Rockwell R	104 – 115	104 – 115	—	Identical
Elastic stored energy (springs)	734 – 894	734 – 894	kJ/m³	Identical
Fatigue strength at 10^7 cycles	23.7 – 30.8	23.7 – 30.8	MPa	Identical
Impact & Fracture Properties
Fracture toughness	2.1 – 2.3	2.1 – 2.3	MPa.m^0.5	Identical
Toughness (G)	1.85 – 2.23	1.85 – 2.23	kJ/m²	Identical
Impact strength, notched, 23 °C	69.7 – 102	10.1 – 83.1	kJ/m²	High visc. is notably tougher (min 69.7 vs 10.1)
Impact strength, notched, -30 °C	12.6 – 15	5.65 – 23.3	kJ/m²	Low visc. has a much wider/lower range at min
Impact strength, unnotched, 23 °C	590 – 600	188 – 226	kJ/m²	High visc. is dramatically tougher (~3x higher)
Impact strength, unnotched, -30 °C	590 – 600	183 – 220	kJ/m²	High visc. is dramatically tougher (~3x higher)
Thermal Properties
Glass temperature	142 – 158	142 – 158	°C	Identical
Heat deflection temperature, 0.45 MPa	138 – 142	134 – 138	°C	High visc. slightly higher
Heat deflection temperature, 1.8 MPa	121 – 132	121 – 132	°C	Identical
Maximum service temperature	104 – 119	101 – 116	°C	High visc. slightly higher
Minimum service temperature	-47 – -37	-47 – -37	°C	Identical
Thermal conductivity	0.189 – 0.205	0.193 – 0.218	W/m.°C	Low visc. slightly higher
Specific heat capacity	1150 – 1250	1150 – 1250	J/kg.°C	Identical
Thermal expansion coefficient	120 – 125	120 – 125	µstrain/°C	Identical
Thermal shock resistance	201 – 226	201 – 226	°C	Identical
Thermal distortion resistance	0.00154 – 0.00168	0.00157 – 0.00179	MW/m	Low visc. slightly higher
Electrical Properties
Electrical resistivity	1e20 – 1e21	1e20 – 1e21	µohm.cm	Identical
Electrical conductivity	1.72e-19 – 1.72e-18	1.72e-19 – 1.72e-18	%IACS	Identical
Dielectric constant (relative permittivity)	3.1 – 3.3	3.1 – 3.3	—	Identical
Dissipation factor (dielectric loss tangent)	8.6e-4 – 9.4e-4	8.6e-4 – 9.4e-4	—	Identical
Dielectric strength (dielectric breakdown)	16 – 19.2	16 – 19.2	MV/m	Identical
Comparative tracking index	175 – 325	175 – 325	V	Identical
Magnetic Properties
Magnetic type	Non-magnetic	Non-magnetic	—	Identical
Optical, Aesthetic & Acoustic Properties
Refractive index	1.58 – 1.59	1.58 – 1.59	—	Identical
Transparency	Optical quality	Optical quality	—	Identical
Acoustic velocity	1.39e3 – 1.43e3	1.39e3 – 1.43e3	m/s	Identical
Mechanical loss coefficient (tan delta)	0.0164 – 0.0172	0.0164 – 0.0172	—	Identical
Critical Materials Risk
Contains >5wt% critical elements?	No	No	—	Identical
Absorption & Permeability
Water absorption @ 24 hrs	0.135 – 0.165	0.135 – 0.165	%	Identical
Water vapor transmission	1.1 – 2.05	1.1 – 2.05	g.mm/m².day	Identical
Permeability (O2)	91.6 – 105	91.6 – 105	cm³.mm/m².day.atm	Identical
Processing Properties
Polymer injection molding	Excellent	Acceptable	—	High visc. rated better for injection molding
Polymer extrusion	Acceptable	Acceptable	—	Identical
Polymer thermoforming	Excellent	Excellent	—	Identical
Linear mold shrinkage	0.5 – 0.7	0.5 – 0.7	%	Identical
Melt temperature	226 – 322	205 – 298	°C	High visc. requires higher melt temperature
Mold temperature	70 – 100	70 – 100	°C	Identical
Molding pressure range	69 – 138	55 – 103	MPa	High visc. requires higher molding pressure
Durability
Water (fresh)	Excellent	Excellent	—	Identical
Water (salt)	Excellent	Excellent	—	Identical
Weak acids	Excellent	Excellent	—	Identical
Strong acids	Excellent	Excellent	—	Identical
Weak alkalis	Acceptable	Acceptable	—	Identical
Strong alkalis	Unacceptable	Unacceptable	—	Identical
Organic solvents	Limited use	Limited use	—	Identical
Oxidation at 500 °C	Unacceptable	Unacceptable	—	Identical
UV radiation (sunlight)	Fair	Fair	—	Identical
Flammability	Slow-burning	Slow-burning	—	Identical
Primary Production Energy, CO2 & Water
Embodied energy, primary production	100 – 111	100 – 111	MJ/kg	Identical
CO2 footprint, primary production	4.53 – 4.99	4.53 – 4.99	kg/kg	Identical
Water usage	165 – 182	165 – 182	l/kg	Identical
Processing Energy, CO2 Footprint & Water
Polymer extrusion energy	5.82 – 6.43	5.78 – 6.39	MJ/kg	High visc. marginally higher
Polymer extrusion CO2	0.437 – 0.483	0.434 – 0.48	kg/kg	High visc. marginally higher
Polymer extrusion water	4.83 – 7.24	4.81 – 7.22	l/kg	High visc. marginally higher
Polymer molding energy	18.7 – 20.6	17.6 – 19.5	MJ/kg	High visc. higher
Polymer molding CO2	1.4 – 1.55	1.32 – 1.46	kg/kg	High visc. higher
Polymer molding water	12.6 – 18.9	12.2 – 18.2	l/kg	High visc. higher
Coarse machining energy (per unit wt removed)	1.09 – 1.2	1.09 – 1.2	MJ/kg	Identical
Coarse machining CO2 (per unit wt removed)	0.0814 – 0.09	0.0814 – 0.09	kg/kg	Identical
Fine machining energy (per unit wt removed)	6.58 – 7.27	6.58 – 7.27	MJ/kg	Identical
Fine machining CO2 (per unit wt removed)	0.494 – 0.546	0.494 – 0.546	kg/kg	Identical
Grinding energy (per unit wt removed)	12.7 – 14	12.7 – 14	MJ/kg	Identical
Grinding CO2 (per unit wt removed)	0.951 – 1.05	0.951 – 1.05	kg/kg	Identical
Recycling & End of Life
Recycle	Yes	Yes	—	Identical
Embodied energy, recycling	35 – 38.7	35 – 38.7	MJ/kg	Identical
CO2 footprint, recycling	2.32 – 2.56	2.32 – 2.56	kg/kg	Identical
Recycle fraction in current supply	0.672 – 0.742	0.672 – 0.742	%	Identical
Downcycle	Yes	Yes	—	Identical
Combust for energy recovery	Yes	Yes	—	Identical
Heat of combustion (net)	30.3 – 31.8	30.3 – 31.8	MJ/kg	Identical
Combustion CO2	2.7 – 2.84	2.7 – 2.84	kg/kg	Identical
Landfill	Yes	Yes	—	Identical
Biodegrade	No	No	—	Identical

Comparison between cast aluminium alloy designations

EN, ISO, AA and JIS designation

EN numerical alloy designation	EN symbolic alloy designation	Corresponding ISO alloy designation	Corresponding AA alloy designation	Corresponding JIS alloy designation
EN AC-21000	EN AC-AlCu4MgTi	Al Cu4MgTi	204.0	AC1B
EN AC-21100	EN AC-Al Cu4Ti	Al Cu4Ti	–	Al-Cu4Ti
EN AC-21200	EN AC-Al Cu5MnMg	–	–	–
EN AC-41000	EN AC-Al Si2MgTi	Al Si2MgTi	–	–
EN AC-42000	EN AC-AlSi7Mg	Al Si7Mg	356.0	AC4C
EN AC-42100	EN AC-Al Si7Mg0.3	Al Si7Mg0.3	A356.0	AC4CH
EN AC-42200	EN AC-AlSi7Mg0.6	Al Si7Mg0.6	357.0	–
EN AC-43000	EN AC-Al Si10Mg(a)	Al Si10Mg	–	AC4A.Al-Si10Mg
EN AC-43100	EN AC-Al Si10Mg(b)	Al Si10Mg	–	AC4A.Al-Si10Mg
EN AC-43200	EN AC-Al Si10Mg(Cu)	Al Si10Mg(Cu)	–	–
EN AC-43300	EN AC-Al Si9Mg	Al Si9Mg	–	–
EN AC-43400	EN AC-Al Si10Mg(Fe)	Al Si10Mg(Fe)	–	ADC3
EN AC-43500	EN AC-Al Si10MnMg	–	365.0	–
EN AC-44000	EN AC-Al Si11	Al Si11	–	–
EN AC-44100	EN AC-Al Si12(b)	Al Si12(b)	B413.0	AC3A.Al-Si12
EN AC-44200	EN AC-Al Si12(a)	Al Si12(a)	–	–
EN AC-44300	EN AC-Al Si12(Fe)(a)	Al Si12(Fe)	A413.0	ADC1
EN AC-44400	EN AC-Al Si9	Al Si9	–	–
EN AC-44500	EN AC-Al Si12(Fe)(b)	–	–	–
EN AC-45000	EN AC-Al Si6Cu4	Al Si6Cu4	–	Al-Si6Cu4
EN AC-45100	EN AC-Al Si5Cu3Mg	Al Si5Cu3Mg	363.0	–
EN AC-45300	EN AC-Al Si5Cu1Mg	Al Si5Cu1Mg	355.0	AC40
EN AC-45400	EN AC-Al Si5Cu3	Al Si5Cu3	–	Al-Si5Cu3
EN AC-45500	EN AC-Al Si7Cu0.5Mg	–	–	–
EN AC-46000	EN AC-Al Si9Cu3(Fe)	Al Si9Cu3(Fe)	–	ADC10
EN AC-46100	EN AC-Al Si11Cu2(Fe)	Al Si11Cu2(Fe)	–	ADC12Z
EN AC-46200	EN AC-Al Si8Cu3	Al Si8Cu3	380.0	AC4B
EN AC-46300	EN AC-Al Si7Cu3Mg	Al Si7Cu3Mg	320.0	–
EN AC-46400	EN AC-Al Si9Cu1Mg	Al Si9Cu1Mg	–	–
EN AC-46500	EN AC-Al Si9Cu3(Fe)(Zn)	Al Si9Cu3(Fe) (Zn)	–	ADC10Z
EN AC-46600	EN AC-Al Si7Cu2	Al Si7Cu2	–	–
EN AC-47000	EN AC-Al Si12(Cu)	Al Si12(Cu)	–	Al-Si12Cu
EN AC-47100	EN AC-Al Si12Cu1(Fe)	Al Si12Cu1(Fe)	–	–
EN AC-48000	EN AC-Al Si12CuNiMg	Al Si12CuNiMg	–	AC8A
EN AC-48100	EN AC-Al Si17Cu4Mg	Al Si17Cu4Mg	8390.0	ADC14
EN AC 51100	EN AC-Al Mg3	–	–	–
EN AC-51200	EN AC-Al Mg9	Al Mg9	518.0	Al-Mg10
EN AC-51300	EN AC-Al Mg5	Al Mg5	–	ADC5, AC7A, Al-Mg6
EN AC-51400	EN AC-Al Mg5(Si)	Al Mg5(Si)	–	Al-Mg5Si1
EN AC-51500	EN AC-Al Mg5Si2Mn	–	–	–
EN AC-71100	EN AC-Al Zn10Si8Mg	Al Zn 10Si8Mg	–	–

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Hot Dip Galvanizing vs. Electrogalvanizing

(Hot Dip Galvanizing vs. Electroplating)

Feature	Hot Dip Galvanizing (ISO 1461)	Electrogalvanizing (ISO 2081 / ISO 19598)
Process	Molten Dip: Fabricated steel is dipped into a bath of molten zinc (approx. 450°C).	Electrolytic: Zinc is deposited onto the steel using an electrical current in a chemical solution.
Coating Thickness	Thick (Heavy Duty): Typically 35 µm to 85 µm (or more). Thickness is largely determined by steel thickness.	Thin (Precision): Typically 5 µm to 25 µm. Thickness is controlled by time and current, specified by the customer.
Bonding Mechanism	Metallurgical Bond: Zinc reacts with iron to form robust zinc-iron alloy layers integral to the steel.	Adhesion: The coating sits on top of the substrate. Adhesion testing is often required.
Appearance	Industrial/Matt: Can be dull grey, shiny, or spangled. Surface may be slightly uneven (“orange peel”).	Bright/Decorative: Typically bright, glossy, and very smooth. Often used where aesthetics are important.
Corrosion Protection	Very High (Long Term): Suitable for harsh outdoor environments. Life is proportional to the heavy thickness.	Moderate (Indoor/Controlled): Good for indoors or mild exposure. Relies heavily on passivation layers (chromates) for protection.
Passivation	Optional: “After-treatments” can be used to prevent wet storage stain, but are not always mandatory.	Mandatory: Almost always requires a conversion coating (passivate) and/or sealant to protect the thin zinc layer.
Suitability for Threads	Difficult: Thicker coating can jam threads. Bolts often require undersizing or centrifuging to clear threads.	Excellent: Thin, controlled coating maintains thread geometry. Ideal for fasteners (screws, nuts).
Hardness & Abrasion	High: The zinc-iron alloy layers are hard and abrasion-resistant.	Lower: Pure zinc is relatively soft; susceptible to scratching if not sealed.
Hydrogen Embrittlement	Low Risk: Generally low risk for standard structural steels. Focus is on venting cavities to prevent explosions.	High Risk: Critical for high-strength steels (≥ 1000 MPa). Requires baking (relief heat treatment) after plating.

NOTE

Electrogalvanizing is NOT “Cold Galvanizing.”

In industrial language, these terms refer to two completely different processes. Confusing them can lead to serious specification errors.

• Electrogalvanizing is an electrolytic plating process (ISO 2081 / ISO 19598).
• “Cold Galvanizing” is a slang term for Zinc-Rich Painting (often used for repair in ISO 1461).

Feature	Electrogalvanizing (Zinc Plating)	“Cold Galvanizing” (Zinc-Rich Paint)
Correct Standard	ISO 2081 or ISO 19598	ISO 1461 (Annex C)
What is it?	A factory process using electricity to deposit zinc in a chemical bath.	A manual process using a spray can, brush, or pistol to apply zinc-dust paint.
Also Known As	Zinc Plating, Electro-zinc, Zinc Electrodeposition.	Zinc Spray, Zinc Paint, Cold Galv, ZRP.
Application	Factory only (Rack or Barrel plating).	On-site repair or touch-up.
Appearance	Shiny, bright, metallic, smooth.	Matt grey, dull, paint-like texture.
Bonding	Adhesion: Zinc sits on the surface.	Mechanical: Binder sticks to the surface (like regular paint).
Primary Use	OEM Parts: Fasteners, automotive parts, small brackets.	Renovation: Repairing damaged hot dip galvanizing or welding spots.

Why the confusion?

The confusion comes from the temperature.

• Hot Dip Galvanizing happens at ~450°C (Hot).
• Electrogalvanizing happens at room temperature (Cold).
• Zinc Painting happens at room temperature (Cold).

Because both electroplating and painting happen at room temperature, non-technical staff sometimes call both “cold.” However, in professional specifications, “Cold Galvanizing” exclusively refers to Zinc-Rich Paint, never to Electroplating.

ISO 1461 vs ISO 2081 vs ISO 19598

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods

DIN 50979 vs ISO 19598 vs ISO 2081

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 2081 vs. ISO 19598

ISO 1461 vs ISO 2081 vs ISO 19598

Table 1: Scope and Process Overview

Feature	ISO 1461	ISO 2081	ISO 19598
Primary Process	Hot Dip Galvanizing: Dipping fabricated articles into molten zinc.	Electroplating: Electrodeposition of zinc.	Electroplating: Electrodeposition of zinc or zinc alloys.
Substrate	Fabricated iron and steel articles (including castings).	Iron or steel.	Iron or steel.
Coating Material	Molten zinc containing not more than 2% other metals.	Zinc.	Zinc OR Zinc Alloys (Zinc-Nickel, Zinc-Iron).
Key Exclusion	Does not apply to continuous sheet, wire, or automatic tube plants.	Does not apply to coatings on sheet, strip, or wire in non-fabricated form.	Not explicitly stated in Scope, but implies fabricated parts (rack/barrel).
Main Application	Heavy-duty corrosion protection (structural steel, outdoor furniture).	Protective and decorative purposes.	High-performance protection (automotive, high-stress) with strict environmental (CrVI-free) compliance.

Table 2: Coating Thickness and Designation

Feature	ISO 1461	ISO 2081	ISO 19598
Typical Thickness	Thick: Generally 35 µm to 85 µm (mean) depending on steel thickness.	Thin: Typically 5, 8, 12, or 25 µm.	Thin: Typically 5, 8, 12 µm (up to ~25 µm).
Thickness Determination	Determined by steel thickness (e.g., steel >6mm requires 85 µm coating).	Determined by purchaser specification in the designation.	Determined by purchaser specification in the designation.
Designation Format	Reference to standard (e.g., “ISO 1461”).	Format: Fe/Zn[Thick]/[Passivation]/[Sealant] (e.g., Fe/Zn12/A).	Format: Fe//[Alloy][Thick]//[Passivation]//[Sealant] (e.g., Fe//ZnNi8//Cn//TO).
Alloy Options	Zinc/Iron alloy layers form naturally during the hot dip process.	Zinc only.	Zn (Zinc), ZnFe (0.3-1.0% Fe), ZnNi (12-16% Ni).

Table 3: Supplementary Treatments (Passivation) & Environmental

Feature	ISO 1461	ISO 2081	ISO 19598
Passivation Chemistry	Not mandatory. “After-treatments” (e.g., to prevent wet storage stain) are allowed but not strictly defined by code.	Allows both Hexavalent Cr(VI) and Trivalent Cr(III) passivations, though warns of REACH bans on Cr(VI).	Strictly Cr(VI)-Free (Hexavalent chromium free) treatments only.
Treatment Codes	None specified in standard designation.	A (Clear), B (Bleached), C (Iridescent), D (Opaque), F (Black).	An (Transparent), Cn (Iridescent), Fn (Black).
Sealants	Not part of the standard designation.	Designated as T (e.g., T2 for organic sealant).	Designated as T (e.g., T2, T7 with optional integrated lubricant codes L/yL).
Hydrogen Embrittlement	Mentions venting/draining to prevent explosions. Low risk for standard steels.	Requires Stress Relief (SR) and Embrittlement Relief (ER) for steels ≥ 1000 MPa.	High Focus: Detailed diagrams on stress/material interaction. Mandatory relief for steels ≥ 1000 MPa.

Table 4: Corrosion Resistance (Salt Spray – NSS)

Feature	ISO 1461	ISO 2081	ISO 19598
Basis of Resistance	Proportional to thickness. Life often predicted in decades (20+ years) in real atmosphere.	Dependent on passivation type and thickness. Measured in hours of Salt Spray Test.	Dependent on Alloy (Ni/Fe), passivation, and thickness. Measured in hours of Salt Spray Test.
Salt Spray Criteria	Warning: Accelerated tests (Salt Spray) should not be used to predict long-term corrosion performance.	Example (Rack, Zn12, Iridescent): • White rust: 120h • Red rust: 264h.	Example (Rack, Zn12, Iridescent): • White corrosion: 120h • Red rust: 264h.
Alloy Performance (NSS)	N/A	N/A	High Performance: ZnNi (Zinc-Nickel) can achieve 720h without red rust.

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 vs. ISO 19598

ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles -Specifications and test methods.

1. Scope & Application

Category	Description
✅ Applies To	Batch Hot Dip Galvanizing of fabricated iron and steel articles (including certain castings).
❌ Excludes	Continuous sheet, wire, and woven/welded mesh.
❌ Excludes	Tube and pipe galvanized in automatic plants.
❌ Excludes	Fasteners (e.g., bolts, nuts) which have their own specific standards.

2. Key Terms & Definitions

Term	Definition
Significant Surface	The part of the article essential for serviceability or appearance (must be covered by coating).
Reference Area	An area (min. 10 cm²) where measurements are taken.
Local Thickness	The average of at least 5 magnetic measurements within one reference area.
Mean Thickness	The average of the Local Thickness values from all reference areas in the sample.

3. Visual Inspection Criteria

Inspect from a distance of not less than 1 meter.

Feature	Status	Requirement / Note
Blisters	❌ REJECT	Raised areas without solid metal beneath are not permitted.
Sharp Points	❌ REJECT	Roughness/points capable of causing injury are not permitted.
Uncoated Areas	❌ REJECT	Must be renovated (see Section 6) or re-galvanized.
Flux/Ash	❌ REJECT	Residues must be removed if they affect use or corrosion resistance.
Dark/Light Areas	✅ ACCEPT	Cellular patterns or dark grey areas are acceptable.
White Rust	✅ ACCEPT	“Wet storage stain” is acceptable if coating thickness is sufficient.
Weld Seepage	✅ ACCEPT	Staining from intermittent welds is acceptable (aesthetic only).

Note on Adhesion: Adhesion testing is not normally carried out. The coating should withstand normal handling. Tests (e.g., cutting) must be agreed upon before galvanizing.

4. Sampling & Testing Protocol

Step A: How Many Articles to Pick?

Select a random Control Sample from the inspection lot.

Lot Size (Articles)	Minimum Control Sample Size
1 to 3	All articles
4 to 500	3 articles
501 to 1,200	5 articles
1,201 to 3,200	8 articles
> 3,200	13 articles (up to 10,000)

Step B: Where to Measure?

Choose reference areas based on the size of the individual article.

Article Size (Significant Surface)	Required Reference Areas	Placement Guide
Large (> 2 m²)	At least 3	Approx. center, and ~100 mm from each end.
Medium (> 100 cm² to ≤ 2 m²)	At least 1	Representative area.
Small (≤ 100 cm²)	1	Group articles to make 10 cm² surface.

⚠️ CAUTION: Do not measure less than 10 mm from edges, flame-cut surfaces, or corners.

Step C: What If It Fails? (Re-Sampling)

If the original control sample fails thickness requirements, follow this procedure.

Step	Action	Outcome
1. Re-Sample	Take a new sample from the lot, twice the size of the original.	–
2. Test	Measure the new sample.	If Pass: Accept the whole lot.
3. Result	If the new sample fails:	If Fail: Reject non-conforming articles (or re-galvanize).

5. Coating Thickness Requirements

A. Standard Articles

Use for items not centrifuged (beams, plates, etc.).

Steel Thickness	Local Thickness (min)	Mean Thickness (min)
> 6 mm	70 µm	85 µm
> 3 mm to ≤ 6 mm	55 µm	70 µm
≥ 1.5 mm to ≤ 3 mm	45 µm	55 µm
< 1.5 mm	35 µm	45 µm
Castings > 6 mm	70 µm	80 µm
Castings ≤ 6 mm	60 µm	70 µm

B. Centrifuged Articles

Use for small parts spun to remove zinc (fasteners, washers).

Article Type	Local Thickness (min)	Mean Thickness (min)
Threads > 6 mm dia.	40 µm	50 µm
Threads ≤ 6 mm dia.	20 µm	25 µm
Other parts ≥ 3 mm	45 µm	55 µm
Other parts < 3 mm	35 µm	45 µm

6. Renovation (Repair) Rules

Strict limits apply to repairing uncoated areas.

Parameter	Limit / Requirement
Max Total Area	0.5% of the total surface area of the article.
Max Spot Size	10 cm² (if larger, re-galvanize).
Min Thickness	100 µm (unless otherwise agreed).
Approved Methods	Thermal zinc spray, zinc paste, or zinc paint (pigment ≥ 80% zinc mass).

7. Engineering & Safety Design

Topic	Requirement / Note
⚠️ Venting (Safety)	Enclosed cavities must have vent/drain holes. Risk of explosion if unvented.
Reactivity	Silicon-killed or ultra-low reactivity steels may not meet Table A thicknesses. (Use next lowest category).
Disputes	In case of dispute, the Gravimetric Method (ISO 1460) takes precedence over magnetic gauges.

ISO 1461 vs ISO 2081 vs ISO 19598

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 vs. ISO 19598

DIN 50979 vs ISO 19598 vs ISO 2081

1. Designation & Syntax Comparison

This table highlights exactly how the “code string” (designation) differs on a blueprint. Note the use of double slashes // versus single slashes /.

Feature	DIN 50979	ISO 19598	ISO 2081
Standard Title	Electroplated Zn & Zn-Alloys (Cr(VI)-free)	Electroplated Zn & Zn-Alloys (Cr(VI)-free)	Electroplated Zn with supplementary treatments
Basis Metal	Fe (Iron/Steel)	Fe (Iron/Steel)	Fe (Iron/Steel)
Separator	Double Slash //	Double Slash //	Single Slash /
Alloy Support	Supports Zn, ZnFe, ZnNi	Supports Zn, ZnFe, ZnNi	Supports Zn Only
Designation Structure	Base // Coating+Thickness // Passivation // Seal	Base // Coating+Thickness // Passivation // Seal	Base / Stress Relief / Coating+Thickness / Passivation / Seal

2. Designation Examples (Real-World Scenarios)

Use this table to show your readers how to translate a requirement between standards.

Scenario	DIN 50979 Designation	ISO 19598 Designation	ISO 2081 Designation
Zinc (12µm), Iridescent Passivation	Fe//Zn12//Cn//T0	Fe//Zn12//Cn//T0	Fe/Zn12/C
Zinc (12µm), Black Passivation, Sealed	Fe//Zn12//Fn//T2	Fe//Zn12//Fn//T2	Fe/Zn12/F/T2
Zinc-Nickel (8µm), Transparent Passivation	Fe//ZnNi8//An//T0	Fe//ZnNi8//An//T0	Not Applicable (ZnNi not covered)
Zinc-Iron (8µm), Black Passivated	Fe//ZnFe8//Fn//T0	Fe//ZnFe8//Fn//T0	Not Applicable (ZnFe not covered)

3. Passivation & Sealing Codes

This table clarifies the specific naming conventions for the surface finish. ISO 19598 provides the most specific sealing codes.

Feature	DIN 50979	ISO 19598	ISO 2081
Transparent / Clear	An	An	A (Clear) or B (Bleached)
Iridescent	Cn	Cn	C
Black	Fn	Fn	F
Olive Green	Not available (implies Cr(VI))	Not available (implies Cr(VI))	D (Opaque)
No Sealer	T0	T0	Omitted from code
Generic Sealer	T2	T2	T2
Sealer w/ Lubricant	Not Defined	T2yL (with lubricant) T2nL (no lubricant)	T4 (Grease/Oil/Lube)

4. Performance Comparison (NSS Test – Red Rust)

This table shows the minimum neutral salt spray (NSS) hours required to reach basis metal corrosion (Red Rust) for Rack Plated parts.

Crucial Note: ISO 19598/DIN 50979 generally demand higher performance than ISO 2081 for the exact same coating thickness.

Coating Type (Rack Plated)	DIN 50979	ISO 19598	ISO 2081
Zinc 8µm Transparent (An/A)	48 hours	72 hours	72 hours
Zinc 12µm Transparent (An/A)	72 hours	96 hours	96 hours
Zinc 8µm Iridescent (Cn/C)	216 hours	264 hours	192 hours
Zinc 12µm Iridescent (Cn/C)	264 hours	336 hours	264 hours
Zinc-Nickel 8µm Transparent	480 hours	720 hours	N/A
Zinc-Nickel 8µm Black (Sealed)	720 hours	720 hours	N/A

5. Summary of Key Differences (For your text content)

This table summarizes the fundamental distinctions between the three standards regarding scope, permissible chemicals, and testing rigor.

Feature	DIN 50979	ISO 19598	ISO 2081
Material Scope	Covers Zinc and Zinc Alloys (ZnNi, ZnFe).	Covers Zinc and Zinc Alloys (ZnNi, ZnFe).	Covers Zinc (Zn) only.
Chromium Content	Strictly Cr(VI)-Free Only permits trivalent or chromium-free passivations.	Strictly Cr(VI)-Free Specifically designed for systems without Hexavalent Chromium.	Mixed Includes codes for both Cr(VI)-free and legacy Hexavalent Cr(VI) types (e.g., Type C, D).
Naming Convention	Uses “n” series (An, Cn, Fn) to explicitly denote Cr(VI)-free “New” systems.	Uses “n” series (An, Cn, Fn) to explicitly denote Cr(VI)-free “New” systems.	Uses Legacy single letters (A, C, F) which may or may not contain Cr(VI) depending on the type.
Testing Rigor (NSS)	High Generally requires longer salt spray hours for the same coating thickness compared to ISO 2081.	High Reflects modern passivation capabilities; requirements are often stricter than ISO 2081.	Baseline Standard requirements are generally lower (e.g., 192h vs 264h for iridescent Zn 8µm).
Status	Legacy (German) Predecessor to ISO 19598; still found on older German automotive drawings.	Current (International) The modern global standard for high-performance, eco-friendly zinc plating.	Current (International) The general default standard for commercial zinc plating.

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 2081 vs. ISO 19598

DIN 50979 Metallic coatings – Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment.

1. Scope and Coating Types

This standard covers electrodeposited coatings applied to iron and steel to provide corrosion protection. It specifically covers three types of galvanic layers:

• Zn: Zinc coating without alloying elements.
• ZnFe: Zinc-Iron alloy containing 0.3% to 1.0% Iron.
• ZnNi: Zinc-Nickel alloy containing 12% to 16% Nickel.

Important Note: This standard is specifically for systems using Cr(VI)-free passivation. Older chromate systems containing hexavalent chromium are not covered here.

2. Designation System (Coding)

The designation on technical drawings must follow the structure below using double slashes (//) as separators.

Structure:

Galvanic Coating DIN 50979 – [Basis Metal] // [Coating Code][Thickness] // [Passivation] // [Sealing]

2.1 Passivation Codes (Cr(VI)-Free)

Passivation creates a conversion layer to protect the zinc. Since these are Cr(VI)-free, the suffix “n” (for “new”) is used.

Code	Type	Appearance	Description
An	Transparent	Colorless to colored iridescent	Often referred to as “Thin-layer passivation”.
Cn	Iridescent	Colored iridescent	Often referred to as “Thick-layer passivation”.
Fn	Black	Black	Color nuances are permissible.

2.2 Sealing Codes

Sealing involves applying organic or inorganic agents (typically ≤ 2 μm thick) to increase corrosion resistance.

Code	Description
T0	Without sealing.
T2	With sealing.

2.3 Designation Examples

• Zinc-Nickel (8µm), Iridescent Passivation, No Seal:DIN 50979 – Fe//ZnNi8//Cn//T0
• Zinc-Iron (8µm), Black Passivation, Sealed:DIN 50979 – Fe//ZnFe8//Fn//T2

3. Ordering Information

When sending parts to an electroplater, the following information must be provided:

1. Tensile Strength: Crucial for hydrogen embrittlement risk assessment.
2. Component Details: Material type, manufacturing method, and heat treatment history.
3. Significant Surfaces: Areas defined on the drawing (dot-dash line) where coating thickness and corrosion rules apply.
4. Designation: The full coating code (from Section 2).

4. Hydrogen Embrittlement (High-Strength Parts)

4.1 Critical Threshold

Steel parts with a tensile strength (Rm) of ≥ 1000 N/mm²are classified as high-strength and are critical regarding hydrogen embrittlement. This includes parts with local hardening (e.g., case-hardened, cold-worked, or welded areas).

4.2 Heat Treatment Requirements

To prevent brittle fracture, heat treatment (baking) is required to promote hydrogen effusion. This should happen after electroplating.

Table 4: Heat Treatment Guidelines

Temperature: Component temperature must reach ( 215 ± 15)° C.

Tensile Strength (Rm​) in N/mm2	Minimum Holding Time (Hours)
1000 to 1250	6 h
1251 to 1450	12 h
1451 to 1600	20 h
1601 to 2000	24 h

Note: Care must be taken to ensure the metallic coating does not act as a diffusion barrier preventing hydrogen escape.

5. Technical Requirements and Testing

5.1 Coating Thickness

Thickness should be measured on the significant surface.

• Preferred Method: X-ray fluorescence (DIN EN ISO 3497).
• Alternative Methods: Microscopic (ISO 1463), Coulometric (ISO 2177), or Magnetic (ISO 2178).

5.2 Adhesion (Thermal Shock Test)

Parts are heated to ( 220 ± 15)° C for 30 minutes and then immediately quenched in water at 15°Cto 20°C

• Pass Criteria: No blistering or peeling of the coating.

5.3 Corrosion Resistance (NSS Test)

Testing is performed via Neutral Salt Spray (ISO 9227).

Pre-test Condition: All passivated parts (except Transparent An types) must be heat aged at 120°C for 24 hours before the salt spray test to simulate real-world curing.

Table 5: Transparent (An) and Iridescent (Cn) Coatings

(WR = White Rust/Coating Corrosion; RR = Red Rust/Base Metal Corrosion)

Coating System	Type	Passivation	Sealer	Barrel/Rack	WR (h)	RR (h) @ 8μm	RR (h) @ 12μm
Zn	Zinc	An (Transp.)	T0 (No)	Barrel	8	48	72
Zn	Zinc	An (Transp.)	T0 (No)	Rack	16	72	96
Zn	Zinc	Cn (Iridesc.)	T0 (No)	Barrel	72	144	192
Zn	Zinc	Cn (Iridesc.)	T0 (No)	Rack	120	216	264
Zn	Zinc	Cn (Iridesc.)	T2 (Yes)	Barrel	120	192	264
Zn	Zinc	Cn (Iridesc.)	T2 (Yes)	Rack	168	264	360
ZnNi	Zn-Nickel	Cn (Iridesc.)	T0 (No)	Barrel	120	720	720
ZnNi	Zn-Nickel	Cn (Iridesc.)	T0 (No)	Rack	192	720	720

Table 6: Black (Fn) Coatings

Coating System	Type	Passivation	Sealer	Barrel/Rack	WR (h)	RR (h) @ 8μm	RR (h) @ 12μm
ZnFe	Zn-Iron	Fn (Black)	T2 (Yes)	Barrel	120	264	360
ZnFe	Zn-Iron	Fn (Black)	T2 (Yes)	Rack	168	360	480
ZnNi	Zn-Nickel	Fn (Black)	T2 (Yes)	Barrel	168	720	720
ZnNi	Zn-Nickel	Fn (Black)	T2 (Yes)	Rack	240	720	720

Note: Corrosion requirements are capped at 720 hours to limit testing costs.

6. Test Report Requirements

The electroplater must provide a report containing:

1. Reference to DIN 50979.
2. Confirmation of conformity to the standard.
3. Name of the electroplater.
4. Process details (Rack vs. Barrel).
5. For High Strength Parts ( ≥ 1000 N/mm²): Explicit certification that measures were taken to minimize hydrogen embrittlement (e.g., heat treatment records).

ISO 19598 Designation | Metallic coatings — Electroplated coatings of zinc and zinc alloys on iron or steel with supplementary Cr(VI)-free treatment

ISO 2081 Designation | Metallic and other inorganic coatings — Electroplated coatings of zinc with supplementary treatments on iron or steel

ISO 2081 vs. ISO 19598

Common Trade Names for Zinc-Flake Coatings

Trade Name	Manufacturer / Owner	Notes
Geomet	NOF Metal Coatings Group	Cr-free; most widely OEM-approved worldwide
Dacromet	NOF Metal Coatings Group	Older generation; contains Cr(VI) unless specified Cr-free
GeoBlack	NOF Metal Coatings	Black variant of Geomet; mainly used for automotive appearance parts
Plus (e.g., GEOMET 500 PLUS)	NOF	Enhanced friction & topcoat systems
Tyrogalv / Schmid Zinc Flake	Atotech / Doerken Schmid	German manufacturer; automotive approvals
Zintek	Atotech	Generic zinc-flake product line
ZingaFlake / Zinga Systems	Zinga Met	Mostly corrosion-protection systems incl. zinc-rich
Zircotec ZF coatings	Zircotec	High-performance variants (less common for fasteners)
ZinKlad	MacDermid Enthone	OEM-approved coating systems (includes zinc-flake)
JS500 / JS600 (Japan)	Yamato / Japanese aplicators	Common in Asian automotive supply chains
Ruspert / Ruspert-S	Nofmet / Metal Coatings Japan	Tri-coat zinc-flake & ceramic system
Magni (e.g., Magni 565, Magni 575)	Magni Coatings (USA)	One of the largest competitors to Geomet; widely OEM-approved
Delta-Magni	Joint programs	Used by US and Asian OEMs
ZFA Coatings	Chinese manufacturers	Widely used in industrial fasteners
Dörken Delta-Protekt (e.g., Delta Protekt KL100, GZ series)	Dörken Coatings (Germany)	Leading zinc-flake brand in EU automotive

Zinc-Flake Coatings – Full Comparison Quick Guide

Brand / Trade name	Typical types / grades	Appearance / Color	Salt spray (typ.)	Thickness (typ.)	Top-coat available?	Notes / OEM / spec
GEOMET (NOF)	321, 360, 500 (500A/500B), 720, 430	Silver-gray; GEOBLACK variants = black.	480-1500+ h depending on grade/topcoat (321 ≈720 h, 500 ≈720-1000 h, 720 >1000 h).	~5-15 μm (adjustable by grade/process).	Yes – PLUS / GEOKOTE topcoats (lubricant / colour / friction tuning). (cdn.simplifiedbuilding.com)	Widely OEM-approved (VW, Toyota, Ford etc.); chromate-free variants available. (Nof Metal Coatings)
GEO-BLACK (NOF)	GEOBLACK 500M, ML, 180	Black (matte → semi-gloss).	~720-2000 h depending on system & topcoat (manufacturer data quotes wide range).	8-15 μm typical.	Yes – black organic topcoats (PLUS black, GEOKOTE).	Designed for appearance + corrosion; controlled μ per ISO 16047.
DACROMET (legacy; NOF products also promoted)	DACROMET 320, 500 (legacy and modern variants)	Silver / dull grey (older chromated types existed).	~240-1000 h (legacy sheets: typical ≥ 500-600 h; depends on grade).	~7-13 μm typical.	Yes – friction/topcoat options for torque control.	Historically used widely in automotive; modern equivalents offered Cr-free to meet regulations.
MAGNI (Magni Coatings / Magni 565 family)	MAGNI 565, 575, 590 etc.	Silver; some black topcoat versions	~480-1000 h (Magni 565 datasheets show 480-1000 h; some docs claim 1000 h).	~5-13 μm (many fastener specs show 5-13 μm). (Magni Coatings)	Yes – duplex (inorganic base + organic topcoat) common.	Magni 565 is widely OEM-specified (many OEM approvals listed in data sheets). (SWD, Inc.)
DÖRKEN / DELTA-PROTECT (Delta-Protekt)	Delta-Protect KL series (KL100 etc.)	Silver / grey; variants with topcoats	~480-1500 h (product-dependent).	~5-15 μm	Yes – Delta Seal, Delta Tone topcoats	Leading EU zinc-flake family; OEM approvals common.
ZINTEK (Atotech / Tyrogalv family)	Zintek / Tyrogalv / Schmid zinc-flake lines	Silver gray	~480-1000 h typical (varies by product)	~5-12 μm	Yes – topcoat / lubricant options	Atotech / Schmid products are used in automotive & industrial markets.
TYROGALV / Schmid Zinc-Flake	Tyrogalv family	Silver / grey	Typical OEM ranges (480-1000 h)	~5-12 μm	Yes	German suppliers-automotive approvals common.
MAGNI / DELTA hybrids (other regional brands)	Magni family, regional variants	Silver / black options	480-1000 h typical	5-15 μm	Yes	Often marketed as OEM-equivalent to GEOMET.
ZINGAFLAKE / Zinga systems	ZingaFlake, Zinga systems	Silver / grey (zinc-rich)	varies; marketed as high corrosion protection (check datasheet)	varies	Yes (topcoats)	Zinga family focused on large-area corrosion protection (not only fasteners).
ZFA (Chinese suppliers / generic zinc-flake)	ZFA-xxx series	Silver / grey	~480-1000 h (vendor dependent)	~6-15 μm	Yes (vendor options)	Widely used in industrial fasteners; verify OEM acceptance per buyer.
ZINCLAD / ZinKlad (MacDermid / Enthone lines)	ZinKlad variants	Silver / grey	varies (covering fastener market)	~5-12 μm	Yes	MacDermid products include zinc-flake families with OEM approvals.
ZIRCOTEC ZF (high-performance)	ZF / Zircotec variants	Grey / specialized finishes	≥720-1000 h (per product)	~8-15 μm	Yes (PTFE / ceramic options)	Specialty, high-temp or friction-controlled types (less common for general fasteners).
JS-series (Japan: JS500 / JS600)	JS500, JS600	Silver / grey	~600-1000 h typical (OEM specs in Asia)	~6-12 μm	Yes	Common in Japanese supply chains; used by Toyota, Honda suppliers.
RUSPERT (Ruspert)	Ruspert / Ruspert-S	Silver / black variants	~480-1000 h (product dependent)	~5-15 μm	Yes	Marketed as Cr-free alternatives in some regions.
Zinc-flake + PTFE / GEOKOTE / GEOKOTE-style	GEOKOTE, PTFE black topcoats	Black / graphite-like	~1000-1500+ h (with right basecoat)	10-18 μm (multi-layer)	Topcoat is the key feature	For low friction, chemical resistance & aesthetic black finish.

EN ISO 10683 Zinc Flake Coating Systems

EN 13858 Zinc Flake Coatings

ISO 10683 vs EN 13858 — Zinc Flake Coatings Comparison

Zinc-Flake Coatings – Quick Selection Guide

(GEOMET / DACROMET / GEO-BLACK / etc.)

Zinc-Flake Coatings – Quick Selection Guide

1) Summary Comparison Table

Coating System	Typical Types / Grades	Appearance / Color	Salt Spray (ISO 9227 NSS)	Typical Thickness	Topcoat Options	Notes
GEOMET 321	321, 321H, 321 Plus	Silver-gray metallic	480-720 h (no red rust)	6-12 μm	Organic lubricated topcoat optional	Most common general-purpose GEOMET; excellent fastener coating
GEOMET 500	500A, 500B, 500 + Topcoat	Silver-gray; slightly darker than 321	720-1000 h	8-12 μm	Integrated lubricant in many variants; additional topcoat optional	Better friction control; used in automotive / structural
GEOMET 720	720, 720A	Silver-gray	1000-1500 h+	8-12 μm	Optional	High corrosion resistance; heavy-duty applications
DACROMET 320	320L, 320D	Silver / dull gray	600-720 h	7-12 μm	Yes (for friction tuning)	Older system; some regions restrict Cr(VI) versions
DACROMET 500	500L, 500B	Medium gray	720-1000 h	8-12 μm	Yes	Higher performance DACROMET; Cr-free versions available
GEO-BLACK®	GEO-BLACK C / D / Plus	Black (matte to semi-gloss)	720-1000 h depending on system	6-15 μm	Usually required; defines gloss + friction	Black aesthetic version of GEOMET family
Zinc-Flake + PTFE Topcoats	GEOKOTE, Dri-To-Coat, black PTFE	Silver, black, or graphite-like	1000-1500+ h	10-18 μm	Required (PTFE/fluoropolymer)	Low-friction, chemical-resistant
Zinc-Al + Organic Hybrid	ZF hybrid coatings (various suppliers)	Silver, dark gray	600-1200 h	8-15 μm	Optional	Economical alternative systems

2) Detailed Quick-Selection Table (Use for Choosing the Right Coating)

A. Appearance / Aesthetic Requirements

Requirement	Recommended Coating	Why
Silver-gray standard fastener finish	GEOMET 321 / DACROMET 320	Widely accepted, economical
Premium high-uniformity silver	GEOMET 500	Better smoothness & friction control
Black finish	GEO-BLACK or GEOMET 321 + black topcoat	Stable color + corrosion resistance
Very dark / graphite appearance	PTFE black topcoat	Smooth feel & chemical resistance

B. Corrosion Resistance Targets

Required NSS Hours	Recommended System
≥ 480 h	GEOMET 321, DACROMET 320
≥ 720 h	GEOMET 500, DACROMET 500, GEO-BLACK
≥ 1000 h	GEOMET 720, GEOMET 500 + topcoat, PTFE systems
≥ 1500 h	GEOMET 720 + high-performance topcoat

C. Friction / Torque-Tension Requirements

Requirement	Recommended System
Standard fasteners	GEOMET 321 + lubricant topcoat
Controlled μ = 0.10-0.18	GEOMET 500A / 500B
Controlled μ = 0.12-0.20 (black)	GEO-BLACK + friction topcoat
Very low friction	Zinc-flake + PTFE topcoat

D. Thickness Selection

Typical Thickness	Where Used
6-10 μm	Standard bolts, nuts, washers, clips
8-12 μm	Structural bolts, chassis components
10-18 μm	Severe corrosion or heavy-duty assemblies
12-25 μm	PTFE-enhanced / multi-layer systems

3) Quick Decision Guide

If you need…

• Lowest cost zinc-flake → DACROMET 320 or GEOMET 321
• Black coating (OEM-friendly) → GEO-BLACK
• Best corrosion resistance → GEOMET 720
• Stable friction (automotive) → GEOMET 500
• Very low friction / chemical resistance → Zinc-flake + PTFE
• Chromium-free requirement → All modern GEOMET systems + Cr-free DACROMET versions

EN ISO 10683 Zinc Flake Coating Systems

EN 13858 Zinc Flake Coatings

ISO 10683 vs EN 13858 — Zinc Flake Coatings Comparison

Common Trade Names for Zinc-Flake Coatings