TOPCOAT WCR

TOPCOAT WCR is a tungsten carbide coating designed as a superior alternative to electrolytically applied (nickel-)chromium when extreme wear resistance is required. A major advantage is that no hexavalent chromium (Cr⁶⁺) is produced during application — an important benefit in light of upcoming EU restrictions on Cr⁶⁺ processes.

WCR is tribologically equivalent to galvanic (nickel-)chromium: surface roughness, sliding behaviour and lubrication characteristics match those of hard chrome.This means that when switching from galvanic chrome to WCR (or WCR+), no modifications to the cylinder head sealing assembly are necessary.

Corrosion resistance is better than electrolytic (nickel-)chromium, especially in sodium chloride, acidic, and alkaline environments. WCR-coatings also offer excellent oxidation resistance at high temperatures. The coating’s extremely high hardness provides outstanding wear resistance, but because this reduces toughness, rods exposed to high tensile forces (e.g., bending or articulation) should be tested beforehand. Griekspoor can perform this test if required.

Further improve corrosion resistance

TOPCOAT WCR offers a durable, pit-free alternative to hard chrome plating with significantly improved wear and corrosion resistance. For additional corrosion protection, a nickel-based superalloy intermediate layer can be applied beneath the WCR topcoating — see TOPCOAT WCR+.

Tailored smooth roughness between Ra 0,03 – 0,6μm

The coating structure — a chromium carbide/tungsten carbide blend in a metal matrix — results in a dense layer with porosity below 0.7%, excellent bond strength and very high wear performance. Surface finishes can be ground as smooth as Ra 0.03μm. Griekspoor can adjust the roughness between Ra 0.03 μm and 0.6 μm to match seal requirements and ensure optimal sealing performance, low friction, no stick-slip and maximum seal lifetime.

Typical applications for TOPCOAT WCR

1. Hydraulic rods and plungers (including sluice gate cylinders)
2. Automotive components
3. Wear-resistant sealing surfaces
4. Sliding bearings and pumps
5. Waste-incinerator firewalls
6. Waste-incinerator firewalls
7. Parts used in chemical plants.