Process for reducing oxygen content in thermally sprayed metal coatings

A method for reducing oxygen content in metal coatings obtained from metal powders containing oxygen, and deposited by gas stabilized plasma spray techniques, comprising the steps of:

• providing an oxygen containing metal powder, said metal powder having a particle size in the range of from about 10 .mu.m to about 500 .mu.m;
• adhering and encapsulating carbon to said metal powder and forming a carbon coated metal powder;
• providing a primary gas to a plasma spray gun, said primary gas being selected from one of nitrogen, argon, or helium, and said primary gas being provided at a flow rate in the range of from about 38 liter/min to about 68 liter/min;
• providing a carrier gas to said plasma spray gun, said carrier gas being selected from one of nitrogen, argon, or helium, and said carrier gas being provided at a flow rate in the range of from about 5 liter/min to about 7 liter/min;
• providing said carbon coated metal powder to said plasma gun at a flow rate in the range of from about 30 gms/min to about 85 gms/min;
• positioning said plasma spray gun at a stand-off distance in the range of from about 100 mm to about 150 mm from a substrate;
• energizing said plasma spray gun with power in the range of from about 28 kW to about 42 kW;
• and
• plasma spraying said carbon coated metal powder onto said substrate and depositing a metal coating on said substrate, said coating having an oxygen content at least 20% by weight less than an oxygen content of said metal powder.