Wear Resistant Chromcarbide Coatings from High Solids Suspension

Thermal spray coatings made from suspension feedstock become relevant in more and more fields of application. This is enabled by a combination of industrial-proven thermal spray equipment and efficiency-optimized feedstock. Wear resistant coatings are one of the biggest shares of coatings that are applied in many industries to improve the lifetime of various components. The advantages of suspension sprayed coatings like low as-sprayed surface roughness, small pores and the thin functional coating thickness are promising features for new applications.

In this study, coatings applied by suspension plasma spraying from a water-based suspension with 70 wt.% Chromcarbide solid particles are investigated for their industrial use. The influence of different spray parameters on the coating roughness, hardness, phase composition and sliding wear performance was studied. Using a high-enthalpy plasma torch (Axial III), coatings were deposited with acceptable deposition efficiency of 40−50 % at a deposition rate of about 2 kg coating per hour and resulted in low porosity, reasonable hardness levels above 900 HV0.3 and smooth surfaces with R_a <2 µm. The coatings were compared in a pin-on-disk sliding wear test against other state of the art coatings from APS and HVAF.