WC-Co or WC-CoCr? Start with the service environment

Choose between WC-Co and WC-CoCr by describing the wear and corrosion conditions first, then checking the powder grade and coating qualification. WC12Co and WC10Co4Cr identify different material systems; a matching particle-size label does not make them interchangeable.

What changes when chromium is present?

Both systems contain tungsten carbide with a metallic binder. WC12Co names a cobalt-bonded system; WC10Co4Cr names a cobalt-chromium-bonded system. Oerlikon’s WC-CoCr literature describes the corrosion-resistance contribution of chromium in its own products. This is useful material-system context, not evidence that a WOCO grade matches a third-party powder or coating.

The complete grade matters

WOCO’s WC12Co overview lists FA103-3 and FA105-3D as agglomerated-and-sintered powders with the same 15–45 µm size designation. Their listed total-carbon ranges differ: 5.2–6.0% and 4.9–5.4%, respectively. Even within one material system, chemistry, grade and manufacturing route must travel together in the purchase specification.

For a hydraulic rod or valve component, provide the actual fluid and wear mechanism rather than asking only for a powder suitable for that component name. A named application is a starting point for discussion; it does not establish a coating life, corrosion-test result or industry approval.

Before changing an existing powder

• Record the current material specification and the reason for the change.
• Compare chemistry, manufacturing route, size method, apparent density and flow requirements.
• Agree on a trial and acceptance criteria for the finished coating.
• Keep powder acceptance and coating qualification as separate records.

Related materials

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