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

摘要

Provided are: a surface-coating material having excellent cracking resistance and peeling resistance and also having excellent high-temperature corrosion resistance properties; and a poppet valve coated with the surface-coating material. A Ni-Cr-Co-based alloy according to the present invention comprises 40.0 to 50.0 mass% of Cr, 10.0 to 20.0 mass% of Co, 0.5 to 5.0 mass% of Nb, 0.01 to 5.0 mass% of Fe and 0.1 to 3.0 mass% of Si, with the remainder being 26.0 to 40.0 mass% of Ni and unavoidable impurities. The Ni-Cr-Co-based alloy may additionally comprise one or more elements selected from Mo, W, Mn, Ti, Al, B and C in a total amount of 5.0 mass% or less, wherein the content of each of Ti and Al is 3.0 mass% or less and the content of each of B and C is 1.0 mass% or less. In the poppet valve according to the present invention, at least a face portion is coated with the Ni-Cr-Co-based alloy.