Defending the Surface

Because corrosion and wear both start at the surface, surface engineering is a front-line defence - especially for stainless and hybrid bearings used in harsh environments.

Passivation

Stainless steels resist corrosion because chromium forms a thin passive oxide film. Passivation (typically a nitric or citric acid treatment) dissolves free iron from the surface and promotes a uniform, protective chromium oxide layer, improving corrosion resistance after machining.

Coatings and Treatments

Beyond passivation, several coatings extend life in special duty: thin dense chrome or DLC (diamond-like carbon) reduce friction and wear; black oxide gives mild corrosion protection and a non-reflective finish; PTFE or MoS2-based solid lubricants help in dry or vacuum duty. For electrically insulated bearings, a ceramic coating on the ring (instead of, or with, ceramic balls) blocks shaft currents that would otherwise cause fluting.

Matching Defence to Environment

The rule is to match the treatment to the threat: wash-down and food acids call for 17-4PH plus passivation; chemical immersion calls for full ceramic; motors with VFD drives call for insulated (hybrid ceramic) construction. Specifying the surface is as important as specifying the size.

How KMK Bearing Applies This

At KMK Bearing (SINO BEARINGS, KMK brand) these principles guide every order we manufacture in Chengdu, China. Our in-house process chain - forging, heat treatment, precision grinding, superfinishing and cleanroom assembly - is built to the standards described above, whether the part is a standard catalog bearing or a custom-engineered solution.

• 20+ years of precision bearing manufacturing
• Materials from chrome steel to 17-4PH stainless steel and full ceramic (ZrO2, Si3N4)
• In-house heat treatment and metrology to P4/P2 (ABEC 7/9) precision
• Custom designs and low-MOQ prototyping from drawings or samples

Discuss your application with kevin@sinoti.com or browse our bearing catalog.

SINO BEARINGS (KMK) - Perfect Quality -- Great Service -- Customized.

Source: SINO BEARINGS