Increasing wear-resistance of parts of mortar pumps by plasma-spraying coatings of composite powders containing boron carbide

摘要

In transportation of mortar, parts of mortar pumps are subjected to abrasive wear by the particles of quartz sand with hardness of 9,0...11,5 GPa. Therefore, hardness of a coating should be not less than 16,0 GPa. The boron carbide-containingpowders are used for the deposition of wear-resistant coatings, Thermal resistance of such coatings at high temperatures is provided by chemical cladding of the particles. Hence, as shown by investigations, hardness of thermal-spray coatings based onboron carbide is within the range of 21,0...25,5 GPa. The calculation procedure is suggested for preliminary evaluation of the level of wear of the mortar pump parts depending upon the operational factors. This procedure allows for capacity of theplasmatron, spraying distance, plasma gas flow rate, consumption of powder and its boron concentration. Optimal values of the process parameters provide an abrasive wear resistance of 13...14 mg/h.