＜Tungsten Carbide-Cobalt Chromium Coating＞
Tungsten carbide coatings are resistant to fretting, abrasion, hammer(impact) and sliding wear. Cobalt-chrome or cobalt-chromium (CoCr) is a metal alloy of cobalt and chromium. Cobalt-chrome has a very high specific strength. Co-Cr alloys show high resistance to corrosion due to the spontaneous formation of a protective passive film composed of mostly Cr2O3, and minor amounts of cobalt and other metal oxides on the surface. As its wide application in biomedical industry indicates, Co-Cr alloys are well known for their biocompatibility.
HVOF sprayed WC-CoCr coatings are very dense(porosity<3%) and can be finished by grinding and super-finishing to less than 1 Ra (mirror-like surface). Other methods such as flame spray and fuse coatings, arc spray, and plasma spray are also used to produce carbide coatings for specific requirements such as rougher finishes.
Thermal sprayed tungsten carbide-cobalt chromium series coatings can be applied for the requirement of wear resistant at low temperature in corrosive environment, such as mining rollers of carrier belts. Working temperature of the coating is up to maximum of 500 °C (930 °F). Moreover, the corrosion resistance equals or surpasses galvanic chromium plating, especially in HCl(hydrochloric acid) environments. Some other addition in the WC-CrCo system performs better corrosion resistance in alkaline (NaOH), sulfuric acid (H2SO 4 ) or saline (NaCl) solutions. Additions will also improve the working temperature to 500 °C to 700 °C or exceed 700 °C.Coatings with finer particle distributions is tougher and denser that can be used in the as-sprayed condition without further finishing.
Typical applications of tungsten carbide-cobalt chromium (WC-CrCo) series coatings include carrier belt rollers, paper machinery rolls, pump seals, slush pump piston rods, dump valves, hydraulic rods, polished rod liners, thermal sprayed alternative to hard chromium plating.
Plus Metal Tech (PMT) provides services of protective and functional coatings, such as wear-resistant, corrosion-resistant, erosion-resistant, conductive and insulative coatings. Our thermal coating service is fully customized. Process choices depend on customer’s demands and the chosen materials. For any questions about surface treatment and enhancement, please do not hesitate to give us the message or email. We welcome for the discussion with you.