Cold spray process using treated metal powder

Abstract

A method of applying a metal comprising titanium to a substrate is disclosed. The method comprises nitriding the surface of metal powder particles comprising titanium by contacting the particles with a first gas comprising nitrogen in a fluidized bed reactor, and depositing the metal powder particles onto the substrate with cold spray deposition using a second gas.

1 . A method of applying a metal comprising titanium to a substrate, the method comprising:
 nitriding the surface of metal powder particles comprising titanium by contacting the particles with a first gas comprising nitrogen in a fluidized bed reactor; and   depositing the metal powder particles onto the substrate with cold spray deposition using a second gas.   
     
     
         2 . The method of  claim 1 , wherein the metal powder particles comprise at least one titanium or titanium alloy selected from grades 5 (Ti—6Al—4V) and 23 (Ti—6Al—4V), according to ASTM B861-10. 
     
     
         3 . The method of  claim 2 , wherein the metal powder particles comprise at least one titanium or titanium alloy selected from Ti—6Al—4V, Ti—3Al—2.5V, Ti—5Al—2.5Sn, Ti—8Al—1Mo—1V, Ti—6Al—2Sn—4Zr—2Mo, α+β Ti—6Al—4V, and near β Ti—10V—2Fe—3Al. 
     
     
         4 . The method of  claim 1 , wherein the metal powder particles after nitriding comprise nitrogen at the particle surface and also comprise an internal particle portion that is free of nitrogen. 
     
     
         5 . The method of  claim 1 , wherein the metal powder particles after nitriding have a surface nitrogen content ranging from 5.96 wt. % to 12.22 wt. % as determined by x-ray photoelectron spectroscopy. 
     
     
         6 . The method of  claim 1 , wherein the metal powder particles after nitriding have a nitrogen:oxygen surface wt. % ratio of from 5.96:26.2 to 12.26:16.75 as determined by x-ray photoelectron spectroscopy. 
     
     
         7 . The method of  claim 1 , wherein the first gas comprises at least 1 vol. % nitrogen. 
     
     
         8 . The method of  claim 1 , wherein the first gas consists essentially of nitrogen. 
     
     
         9 . The method of  claim 1 , wherein the fluidized bed reactor is operated at a temperature of 500° C. to 850° C. 
     
     
         10 . The method of  claim 1 , wherein the first gas is at a pressure of 0.11 to 0.12 MPa. 
     
     
         11 . The method of  claim 1 , wherein the space velocity of the first gas in the fluidized bed reactor is from 1 min −1  to 30 min −1 . 
     
     
         12 . The method of  claim 1 , wherein the metal powder particles are contacted with the first gas in the fluidized bed reactor for at least 1 minute. 
     
     
         13 . The method of  claim 1 , wherein the second gas comprises helium. 
     
     
         14 . The method of  claim 13 , wherein the second gas further comprises nitrogen. 
     
     
         15 . The method of  claim 13 , wherein the second gas consists essentially of helium. 
     
     
         16 . The method of  claim 1 , wherein the second gas is at a temperature of 20° C. to 850° C.