Coating thickness is the specification line most buyers leave vague and most suppliers are happy to leave vague, because it is where cost and corrosion performance are both decided. The instinct to ask for "thick plating" is usually wrong. Here is how to think about it.
Thickness is a trade-off, not a maximum
| Too thin | Too thick |
|---|---|
| Lower cost, minimal effect on appearance | Better wear and corrosion resistance |
| May fail corrosion and wear requirements | Higher cost; can push threads and mating surfaces out of tolerance |
The target is "enough and economical," not "as much as possible."
How to choose by part type
- Indoor decorative parts (lighting, furniture hardware): appearance-driven. Decorative chrome is thin; what matters is an even, bright nickel undercoat.
- Bath hardware and faucets: constant exposure to moisture, so they need enough nickel thickness for corrosion life, usually a heavier nickel undercoat plus decorative chrome.
- Outdoor or high-humidity parts: the highest corrosion requirement. Increase nickel thickness, and consider a duplex nickel system.
- Functional wear parts (hard chrome): far thicker than decorative work, targeting wear resistance and dimensional restoration.
- Wire baskets and racks (pull-out baskets, fryer baskets, pet cages): balance appearance and corrosion; food-contact uses also require a report-scope review for the actual product and process.
How thickness is measured
- X-ray (XRF): non-destructive, fast, good for production sampling.
- Cross-section microscopy: destructive, precise, used for first-article approval and disputes.
- Magnetic or eddy-current gauges: portable and quick, less precise, substrate dependent.
How to write it into the spec
State a range, not a single number, plus the significant surface and the measurement method: for example, "20 to 30 microns nickel on the significant surface, verified by XRF." "Adequate thickness" is a future argument. See technology and certification.
FAQ
Is thicker always more durable?
No. Beyond the requirement, extra thickness only adds cost and can affect fit on threads and mating faces. Match it to the application.
Can you hold thickness to our drawing?
Yes. We control coating thickness to your specification and verify by X-ray or cross-section.
How does thickness relate to salt spray?
A thicker, denser deposit, especially the nickel layer, generally means longer salt spray life. See why salt spray tests fail. Request a quote.