HVOF sprayed coatings by customized cermet materials for specific applications

摘要

High velocity oxy-fuel(HVOF)sprayed cermet coatings are required in various industrial fields due to their excellent properties,such as combination of wear resistance,corrosion resistance,high hardness,high bonding strength and stability under high temperature.In order to utilize them in the fields,optimization of composition and structure of the coatings are essentially important meaning that both spray powders and spray conditions are key process parameters.In this paper,developed spray powders of cermet materials are introduced for the specific applications,where ① cavitation erosion,② mechanical impact,③ corrosion by molten alloy and ④ general abrasive wear are major factors that damage the coatings.In order to solve these factors,HVOF coatings of ① WC/Co/Cr with large WC particle,②WC/Cr3C2/Ni with addition of metal or alloy,③ MoB/CoCr composed of double boride and ④WC particle size in WC based cermet,are proposed and these merits are described.