Spring Finishes & Coatings — Zinc, Black Oxide, Powder Coat, Passivation
Quick answer: Zinc plating and powder coating protect carbon steel springs from rust, black oxide gives light protection, and stainless steel springs are passivated; high-strength plated springs may need baking to reduce hydrogen embrittlement risk.
By Gurudatta Trading Co., Mumbai · Updated 2026-09-29
Common spring finishes
| Finish | Protection | Notes |
| Zinc plating | Good general corrosion protection | High-strength springs may need baking after plating to reduce hydrogen embrittlement risk |
| Black oxide | Light protection | Usually combined with oil; suits dry, indoor use |
| Powder coat / paint | Thicker barrier, colour options | Adds thickness; check fit on rods and in bores |
| Oiling / plain | Temporary | Lowest cost for short-term protection |
| Passivation (stainless) | Improves corrosion resistance | Removes surface iron; not a coating |
How to choose
Match the finish to the environment (indoor, outdoor, wet, chemical), the working stress and any fit tolerances. Coating thickness can change the spring's outer diameter slightly, so mention it when tolerances are tight. See also material comparison.
Need springs made to your specification?
Gurudatta Trading Co. (Mumbai, since 2000, ISO 9001:2015) manufactures compression, extension and torsion springs to drawing or sample. Use the free Spring Rate Calculator or message us on WhatsApp.
FAQs
Which coating is best for spring corrosion protection?
Zinc plating and powder coating are common for carbon steel; stainless steel springs rely on the material and passivation.
Can plating make a spring brittle?
High-strength steel springs can suffer hydrogen embrittlement from plating, which is why baking after plating is often specified.
Does powder coating change spring dimensions?
Yes, it adds a small thickness, so tell the manufacturer if fit tolerances are tight.