TOPCOAT WCR+

TOPCOAT WCR+ is the upgraded version of TOPCOAT WCR, designed for situations where extreme wear resistance must be combined with significantly improved corrosion protection. The coating consists of a TOPCOAT 177 UHCR nickel-based superalloy intermediate layer topped with our tungsten carbide WCR coating. This combination improves corrosion resistance and long-term reliability while maintaining the same high wear performance as WCR.

The tungsten carbide top coating is tribologically equivalent to electrolytic(nickel-)chromium: surface roughness, lubrication behaviour and sliding characteristics match those of hard chrome. WCR+ offers superior corrosion resistance compared to galvanic (nickel-)chromium, especially in sodium chloride, acidic and alkaline environments.

Due to the extremely high hardness of tungsten carbide, toughness can sometimes be reduced. However, if impact damage does occur, the TOPCOAT 177 intermediate layer continues to protect the underlying substrate from corrosion — a key advantage of the “+” construction.

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

The coating structure is dense (porosity < 0,7%), enabling very smooth finishes down to Ra 0,03μm. Griekspoor can adjust roughness between Ra 0,03μm and 0,6μm depending on the seal type, ensuring optimal sealing properties, low friction, no stick-slip and maximum seal lifetime.

Further improve corrosion resistance

TOPCOAT WCR+ is designed for severe maritime and chemical environments where both extreme wear resistance and enhanced corrosion protection are required. It can serve as a high-end alternative to galvanic hard chrome plating, offering up to three times better wear resistance and significantly improved corrosion resistance without pitting.

In very severe environments, increasing the intermediate thickness to approximately 200μm can further enhance corrosion resistance.

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
5. Pumps
6. Waste incinerator firewalls
7. Components used in chemical plants