TOPCOAT® WCR (tungsten carbide) coating is especially developed as a hard chrome replacement, a better alternative to electrolytically applied (nickel-)chromium, when extreme wear resistance is required. A major advantage is that no 6-valent chromium is formed during production. There are plans to ban 6-valent chromium from EU based production processes, however the definite date this ban will commence has been postponed several times.
TOPCOAT® WCR is tribologically equivalent to an electrolytic (nickel-)chromium coating meaning that surface roughness, sliding properties, etc. are the same. If WCR (or WCR+) is chosen in favour of electrolytic (nickel-)chromium the sealing assembly in the cylinder head does not need modification.
Corrosion resistance is better than electrolytic (nickel-)chromium, especially in sodium chloride, acidic, and alkaline environments. WCR coatings are also highly resistant to oxidation (high temperatures). A WCR coating is extremely hard, which may interfere with the toughness of the coating. For rods that may be subject to large tensile forces (through articulation and/or bending) it is advisable to first perform a test. If necessary Griekspoor can perform this test.
Wear-resistance and hardness are excellent. During the lifetime of the coated product there is minimal wear on all surfaces. The tribological characteristics and lubrication remain consistently high. For extra corrosion protection Griekspoor can apply a nickel based superalloy intermediate coating under the WCR coating. For this coating please refer to TOPCOAT® WCR+.
Typical applications for WCR are:
- Hydraulic parts, for instance piston rods
- Components for the automotive industry
- Wear resistant seal surfaces
- Wear resistant sliding bearings