Cermet powder, protective-coating-coated member and method of producing same, and electroplating-bath-immersed roll and method of producing same

Abstract

Disclosed is a cermet powder that enables preparation of a cermet coating having both high wear resistance and high corrosion resistance against a strong acid having a pH of less than 1. The disclosed cermet powder contains tungsten carbide particles in an amount of 40 mass % or more; molybdenum carbide particles in an amount of 10 mass % to 40 mass %; and Ni or a Ni alloy as a matrix metal, wherein the cermet powder further contains chromium, either as a carbide or a metal or alloy element contained in the matrix metal, in an amount of 8 mass % or more.

1 . A cermet powder containing:
 tungsten carbide particles in an amount of 40 mass % or more;   molybdenum carbide particles in an amount of 10 mass % to 40 mass %; and   Ni or a Ni alloy as a matrix metal, wherein   the cermet powder further contains chromium, either as a carbide or a metal or alloy element contained in the matrix metal, in an amount of 8 mass % or more.   
     
     
         2 . The cermet powder according to  claim 1 , wherein the tungsten carbide particles have a content of 70 mass % or less. 
     
     
         3 . The cermet powder according to  claim 1 , wherein the tungsten carbide particles have a particle size distribution within a range of 0.1 μm to 6 μm. 
     
     
         4 . The cermet powder according to  claim 1 , wherein the molybdenum carbide particles have a particle size distribution within a range of 0.1 μm to 6 μm. 
     
     
         5 . A protective-coating-coated member comprising:
 a stainless steel base member; and   a cermet coating formed on the stainless steel base member, wherein   the cermet coating comprises a matrix made of Ni or a Ni alloy, in which tungsten carbide particles and molybdenum carbide particles are dispersed, and   the cermet coating contains the tungsten carbide particles in an amount of 40 mass % or more, the molybdenum carbide particles in an amount of 10 mass % to 40 mass %, and chromium, either as a carbide or a metal or alloy element contained in the matrix, in an amount of 8 mass % or more.   
     
     
         6 . The protective-coating-coated member according to  claim 5 , wherein the tungsten carbide particles have a content of 70 mass % or less. 
     
     
         7 . The protective-coating-coated member according to  claim 5 , wherein the tungsten carbide particles in the cermet coating have a particle size distribution within a range of 0.1 μm to 6 μm. 
     
     
         8 . The protective-coating-coated member according to  claim 5 , wherein the molybdenum carbide particles in the cermet coating have a particle size distribution within a range of 0.1 μm to 6 μm. 
     
     
         9 . The protective-coating-coated member according to  claim 5 , wherein the cermet coating has a surface roughness Ra of 0.5 μm to 10 μm. 
     
     
         10 . A method of producing a protective-coating-coated member, comprising thermal spraying the cermet powder as recited in  claim 1  onto a stainless steel base member. 
     
     
         11 . The method of producing a protective-coating-coated member according to  claim 10 , wherein the thermal spraying is HVOF thermal spraying. 
     
     
         12 . An electroplating-bath-immersed roll comprising the protective-coating-coated member as recited in  claim 5 . 
     
     
         13 . An electroplating-bath-immersed roll comprising a roll shaft portion and a roll body portion, both made of stainless steel, wherein
 only the roll body portion comprises the protective-coating-coated member as recited in  claim 5 .   
     
     
         14 . A method of producing an electroplating-bath-immersed roll, the method comprising:
 preparing a roll member comprising a roll shaft portion and a roll body portion, both made of stainless steel; and   forming a cermet coating only onto the roll body portion by thermal spraying the cermet powder as recited in  claim 1 .   
     
     
         15 . The method of producing an electroplating-bath-immersed roll according to  claim 14 , wherein the thermal spraying is HVOF thermal spraying.