Patent ID: 7172821

Claim:
A coating material on a vane in a pump comprising: a first layer adapted to be deposited on a base material, said first layer being made of a Mâ€”Crâ€”Mo alloy consisting of Cr, Mo, at least one of Si and B, M selected from the group consisting of Ni and Co, and carbon as an unavoidable impurity; and a second layer deposited on said first layer, said second layer being made of a hard material containing carbide and a metal component, said first layer serving as a barrier for preventing carbon from being diffused from said second layer into the base material to prevent the base material from being carburized wherein said second layer is made of a Co-base alloy or a Ni-base alloy which has a function for giving a hardness to said second layer by carbide which is contained in advance in the coating material or by carbide which is precipitated in said second layer when said second layer is deposited on said first layer.