Zinc and zinc nickel plating provide corrosion protection for steel. Zinc plating is an electrochemical process that deposits a thin layer of zinc onto steel. It protects against white and red corrosion but government regulations and industry standards have increased minimum corrosion protection requirements. Zinc nickel plating deposits both zinc and nickel onto steel, providing greater hardness and minimum 750 hours to white corrosion and 2000 hours to red corrosion. It has become a replacement for zinc plating and cadmium plating due to its superior properties and compliance with environmental regulations.

1. ZINC and
ZINC NICKEL PLATING
Benefits and Uses

2. Zinc Plating
Why use zinc plating?
• Provides a barrier layer against corrosion to bare steel
• Zinc is a sacrificial coating and will corrode (white
corrosion) before the steel begins to (red rust)
• Final product is cosmetically pleasing
• Can be plated in either clear, yellow, black, olive drab,
and many other dyed colors
• Finish is uniform and very bright

3. Zinc Plating

4. Zinc Plating
• Application of zinc plating
• Electrochemical process that applies a thin layer of zinc
metal to the bare steel surface
• The plating can be either done in rack or barrel
• Thickness of the plating is usually between .0002” and
.0005”

5. Zinc Plating
• Application of zinc plating
• A supplementary chromate coating can be applied to
provide additional corrosion protection
• This provides the color to the plating and can be
either hexavalent or trivalent chrome or a chrome
free passivate
• Sealants can used to increase resistance to white
corrosion as well as modify and lower the coefficient
of friction

6. Zinc Plating
• Issues with zinc plating
• Government Regulations
• REACH and RoHS
• Plating suppliers were required to provide alternative
finishes that did not use hexavalent chromium
• Existing finishes that were compliant did not provide
the necessary corrosion protection
• Great strides have been made to replace hex chrome
and now a trivalent chromate in both yellow and clear is
the industry standard
• ELV was one of the first such clear trivalent chromates
to be available and in use at Saporito

7. Zinc Plating
• Issues with zinc plating
• Industry Standards
• Increased corrosion protection requirements
• 10 years ago the standard was 72 hours to white
corrosion and 240 hours to red rust when testing
with a 5% neutral salt spray test
• Standard requirements have risen to over 120 hours
to white corrosion and 360 hours to red
• Again the plating suppliers are having to find
alternatives

8. Zinc Nickel Plating
• Introduced as an alternative to Cadmium Plating
• Government regulations on cadmium led to need in the
industry for coatings that provide similar properties with
environmentally safe products

9. Zinc Nickel Plating
• What is Zinc Nickel Plating
• Same process as zinc plating but both zinc and nickel
are deposited on bare steel at the same time
• Deposits range from 5% to 20% nickel with the
remainder zinc
• Can be processed in both rack and barrel
• Chromate coatings can be applied to increase
corrosion protection
• Like zinc plating they are available in clear, yellow,
and black
• Sealants are available to reduce the coefficient of
friction

10. Zinc Nickel Plating

11. Zinc Nickel Plating
• Advantages of Zinc Nickel Plating
• Hardness
• Typical hardness value of the as deposited coating is 3
times higher than zinc plating
• Corrosion Protection
• Far and away the superior coating in terms of
corrosion protection to both white and red corrosion
• Can achieve a minimum of 750 hours to white and
2000 hours to red rust

12. Corrosion Protection of Coatings
Red
White

13. Zinc Nickel Plating
• Advantages of Zinc Nickel Plating
• Variety of Industries Serviced
• Marine applications
• Agriculture
• High resistance to fertilizer
• Automotive
• Electronics
• Corrosion products not as loose and voluminous as
with zinc plating

14. Zinc Nickel Plating
• Advantages of Zinc Nickel Plating
• Throwing Power
• Has excellent coverage in both low current and high
current areas
• This provides a very uniform coating on the most
complex of shapes

15. Zinc Nickel Plating
• Drawback of Zinc Nickel Plating
• Appearance
• Very functional coating but a difference in cosmetics
from zinc plating
• Due to addition of nickel in the deposit the clear
coating has a lot of iridescent to it
• However the black chromate is uniform and is
superior to zinc trivalent black chromates

16. Zinc Nickel Plating

17. Zinc Nickel Plating
• Drawback of Zinc Nickel Plating
• Yellow Chromate
• At this time the yellow chromate is only supplied in
the hexavalent form
• Only clear and black would be both REACH and
RoHS compliant

18. Summary
• Zinc plating has been around for a long time and
provides a very good coating for most industries
• Government regulations and industry corrosion
requirements have outpaced existing zinc technologies
• Zinc Nickel has been introduced as a suitable replacement
for Zinc plating
• Zinc Nickel provides maximum hardness and corrosion
protection that is well beyond industry requirements

19. Questions?
Email us at steve@saporitofinishing.com
Call us at 708-222-5300