| CPC B22F 12/53 (2021.01) [B22F 10/25 (2021.01); B33Y 10/00 (2014.12); B33Y 30/00 (2014.12); C22C 38/44 (2013.01); C22C 38/46 (2013.01)] | 15 Claims | 

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               1. A method of 3D printing an item, comprising the step of: 
            spraying from a spray nozzle, a spray material comprising a powder entrained in an oxygen comprising carrier gas, wherein the spray nozzle comprises a constricted throat that has: 
                i. a thermal conductivity of at least 10 W/mk; 
                ii. a hardness of at least 10 Rockwell C (HRC), wherein the constricted throat comprises between 5% and 30% by volume of: 
                chromium carbide; 
                  iron carbide; 
                  vanadium carbide; or 
                  any combination of chromium carbide, iron carbide and vanadium carbide; and 
                iii. a temperature of the constricted throat does not exceed 250° C. 
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