METHOD FOR CURING SURFACE OF Co-Cr-W BASED CAST ALLOY

摘要

PURPOSE: A method for forming a surface curing layer with a uniform thickness on Co-Cr-W based cast alloy by plasma diffusion is provided. CONSTITUTION: In a surface curing method of Co-Cr-W based cast alloy, the method is characterized in that the plasma nitriding using pulse direct current is operated at 550 to 700 deg.C in an atmosphere of 100 % nitrogen gas or in an atmosphere containing less than 75 % hydrogen gas and a balance of nitrogen gas for at least 8 hours, wherein voltage of the pulse direct current is 400 to 600 V, pulse-on is 100 to 500 μs and pulse-off is 100 to 850 μs.