Surface Treatments Explained: Zinc, Geomet/DACROMET, and Passivation for Corrosion Resistance

A spring's material choice gets most of the attention, but the surface treatment applied afterward often determines whether that part survives its intended environment. Here's a practical guide to the finishes we apply most often.

PLATING OPTIONS

• Zinc plating. Cost-effective corrosion protection for general industrial applications.
• Nickel plating. Improved corrosion and wear resistance with a bright, uniform finish.
• Chrome plating. High hardness and corrosion resistance, often used where surface durability is critical.
• Tin plating. Improves solderability and conductivity — common on components with an electrical function.

CHEMICAL & MECHANICAL FINISHES

• Passivation. Removes free iron from stainless steel surfaces to maximize corrosion resistance, especially important for medical and food-contact parts.
• Black oxide. A thin, low-cost conversion coating offering mild corrosion resistance and reduced light reflectivity.
• Phosphate coating. Improves paint/coating adhesion and provides a base layer of corrosion protection.
• Geomet / DACROMET. High-performance corrosion-resistant coatings widely used in automotive and aerospace applications, without the hydrogen embrittlement risk of some electroplating processes.
• Electro-polishing. Removes surface imperfections and improves both corrosion resistance and cleanliness — common in medical applications.
• Shot peening. A mechanical process that improves fatigue life by introducing beneficial compressive surface stress.

CHOOSING THE RIGHT FINISH

The right finish depends on your operating environment — humidity, chemical exposure, electrical function, or biocompatibility requirements all point toward different treatments. Tell us the conditions your part will face and we'll recommend a finish to match.

Published by the Seyunda Team · 2026