Ni-cr-al chromium carbide powder

Abstract

Disclosed herein are improved chromium carbide alloy which possess improved properties as related to previous developments. The utilization of aluminum in the alloy can enhance the high temperature oxidation resistance. Embodiments of alloys were designed to simultaneously possess 1) a low liquidus temperature which enables easy atomization on an industrial scale, and 2) a microstructure of a gamma matrix and Cr7C3 carbide precipitates which enables high temperature stability and retention of advantageous properties at high temperatures.

1 . A thermal spray feedstock comprising:
 Ni;   Al: about 1.0 wt. %-about 3.0 wt. %;   C: about 3.5 wt. %-about 5.5 wt. %; and   Cr: about 47.5 wt. %-about 57.5 wt. %;   wherein the feedstock is configured to form CrC carbides.   
     
     
         2 . (canceled) 
     
     
         3 . The thermal spray feedstock of  claim 1 , wherein the CrC carbides comprise Cr 7 C 3  carbides. 
     
     
         4 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, a total Cr 7 C 3  fraction at 1300K of about 40 mole % or greater. 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, a temperature range of at least about 400K when Cr 7 C 3  carbides are the only carbides present. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, a temperature range of a single-phase FCC_A1 matrix of at least about 200K. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, a weight percentage of aluminum content in a single phase FCC_A1 matrix at 1500K of above about 2%. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, a liquidus temperature of below about 1975K. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation 0.7≥y+6.36x, x being equal to a weight % of Al in an FCC_A1 matrix at 1500K and y being equal to a phase mole fraction of Cr 7 C 3  at 1500K. 
     
     
         20 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−6)≥y−0.20x≥(−9), x being equal to a wt. % Ni and y being equal to a wt. % Al. 
     
     
         21 . The thermal spray feedstock of  claim 1 , wherein the feedstock is characterized by having, under thermodynamic conditions, as meeting the equation (−0.4)≥y−0.1x≥(−1.5), x being equal to a wt. % Cr and y being equal to a wt. % C. 
     
     
         22 . The thermal spray feedstock of  claim 1 , wherein the thermal spray feedstock is boron free. 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . The thermal spray feedstock of  claim 1 , wherein the thermal spray feedstock is a powder. 
     
     
         30 . A hardfacing coating formed from the thermal spray feedstock of  claim 1 , comprising CrC carbides. 
     
     
         31 . The hardfacing coating of  claim 30 , wherein the coating has at least about 40 area % of Cr 7 C 3  particles. 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . The hardfacing coating of  claim 30 , wherein the coating has a matrix comprising a total Al content of about 4 weight % or higher. 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . The hardfacing coating of  claim 30 , wherein the coating has an ASTM G65B volume loss of less than about 35 mm 3 . 
     
     
         38 . (canceled) 
     
     
         39 . (canceled) 
     
     
         40 . The hardfacing coating of  claim 30 , wherein the coating has an ASTM G32 volume loss of less than about 5 mm 3  after 1200 minutes. 
     
     
         41 . (canceled) 
     
     
         42 . (canceled) 
     
     
         43 . The hardfacing coating of  claim 30 , wherein the coating has a Vickers hardness of greater than about 500 HV 0.3 . 
     
     
         44 . (canceled) 
     
     
         45 . (canceled) 
     
     
         46 . The hardfacing coating of  claim 30 , wherein the coating can last over about 500 hours before failing under ASTM B117 salt spray testing. 
     
     
         47 . (canceled) 
     
     
         48 . (canceled) 
     
     
         49 . (canceled) 
     
     
         50 . A powder feedstock comprising:
 Ni;   Al: about 5.6 wt. %-about 8.4 wt. %;   C: about 3.6 wt. %-about 5.4 wt. %; and   Cr: about 37.6 wt. %-about 56.4 wt. %;   wherein the powder feedstock is configured to form CrC carbides.   
     
     
         51 . (canceled) 
     
     
         52 . (canceled)