Metal powder including diffusion alloyed molybdenum

Abstract

Metal powders for surface coating are disclosed. The metal powders comprise molybdenum diffusion alloyed to the base powder particles. Metal powders comprising a prealloyed powder and a molybdenum source are also disclosed.

What is claimed is:  
     
         1 . A metal powder for surface coating, the metal powder consisting essentially of particles of a prealloyed powder and from about 4% to about 15% by weight of Mo diffusion alloyed to the particles of the prealloyed powder, the prealloyed powder comprising Fe and optionally at least one element selected from the group consisting of C, Si, Mn, Cr, V, Mo and W, the balance being inevitable impurities.  
     
     
         2 . The metal powder of  claim 1 , wherein the amount of molybdenum diffusion alloyed to the particles of the prealloyed powder is from about 6% to about 10% by weight of the metal powder.  
     
     
         3 . The metal powder of  claim 1 , wherein the amount of molybdenum diffusion alloyed to the particles of the prealloyed powder is from about 4% to about 10% by weight of the metal powder.  
     
     
         4 . The metal powder of  claim 1 , wherein the prealloyed powder is an atomized powder.  
     
     
         5 . A surface coating formed by applying the metal powder according to  claim 1  on a substrate by a thermal spraying process.  
     
     
         6 . A surface coating formed by applying the metal powder according to  claim 1  on a substrate by a weld cladding process.  
     
     
         7 . A metal powder for surface coating, the metal powder comprising particles of a prealloyed powder and from about 4% to about 15% by weight of Mo as the only element diffusion alloyed to the particles of the prealloyed powder, the prealloyed powder comprising Fe and optionally at least one element selected from the group consisting of C, Si, Mn, Cr, V, Mo and W, the balance being inevitable impurities.  
     
     
         8 . The metal powder of  claim 7 , wherein the amount of molybdenum diffusion alloyed to the particles of the prealloyed powder is from about 6% to about 10% by weight of the metal powder.  
     
     
         9 . The metal powder of  claim 7 , wherein the amount of molybdenum diffusion alloyed to the particles of the prealloyed powder is from about 4% to about 10% by weight of the metal powder.  
     
     
         10 . The metal powder of  claim 7 , wherein the prealloyed powder is an atomized powder.  
     
     
         11 . A surface coating formed by applying the metal powder according to  claim 7  on a substrate by a thermal spraying process.  
     
     
         12 . A surface coating formed by applying the metal powder according to  claim 7  on a substrate by a weld cladding process.  
     
     
         13 . A metal powder for surface coating, the metal powder being produced by heating a mixture consisting essentially of a prealloyed powder and a molybdenum-containing powder, the metal powder comprising from 4% to 15% by weight of Mo as the only element diffusion alloyed to the particles of the prealloyed powder, the prealloyed powder comprising Fe and optionally at least one element selected from the group consisting of C, Si, Mn, Cr, V, Mo and W, the balance being inevitable impurities.  
     
     
         14 . The metal powder of  claim 13 , wherein the mixture is heated at a temperature that is (i) sufficiently high to ensure diffusion of molybdenum into the prealloyed powder and (ii) lower than a temperature required for complete pre-alloying.  
     
     
         15 . The metal powder of  claim 13 , wherein the molybdenum-containing powder is MoO 3  or metallic molybdenum powder, and the mixture is heated in a reducing atmosphere at a temperature between 750° C. and 900° C.  
     
     
         16 . The metal powder of  claim 13 , wherein the amount of molybdenum diffusion alloyed to the base powder particles is from about 6% to about 10% by weight of the metal powder.  
     
     
         17 . The metal powder of  claim 13 , wherein the amount of molybdenum diffusion alloyed to the base powder particles is from about 4% to about 10% by weight of the metal powder.  
     
     
         18 . The metal powder of  claim 13 , wherein the prealloyed powder is an atomized powder.  
     
     
         19 . A surface coating formed by applying the metal powder according to  claim 13  on a substrate by a thermal spraying process.  
     
     
         20 . A surface coating formed by applying the metal powder according to  claim 13  on a substrate by a weld cladding process.