Ni-Cr-Co Ni-Cr-Co-BASED ALLOY HAVING HIGH-TEMPERATURE CORROSION RESISTANCE PROPERTIES AND POPPET VALVE HAVING SURFACE MODIFIED WITH SAME

摘要

A surface coating material excellent in crack resistance and peel resistance and having excellent high temperature corrosion resistance property and a poppet valve coated with the surface coating material are provided. The Ni-Cr-Co alloy according to the present invention contains Cr in an amount of 40.0 to 50.0 mass%, Co in an amount of 10.0 to 20.0 mass%, Nb in an amount of 0.5 to 5.0 mass%, Fe in an amount of 0.01 to 5.0 mass%, Si in an amount of 0.1 to 3.0 mass% And the balance of 26.0 to 40.0 mass% of Ni and inevitable impurities. The total amount of elements selected from Mo, W, Mn, Ti, Al, B and C may be 5.0 mass% or less. In this case, Ti and Al are each 3.0 mass% or less, B and C are 1.0 mass %. In the poppet valve of the present invention, the above Ni-Cr-Co alloy is coated on at least the entire surface of the head.