| 摘要 |
PURPOSE:To enhance the corrosion resistance of steel parts in a corrosive atmosphere at high temp., by spraying a molten Ni alloy having a specified composition on the surface of each of the parts and by carrying out chromizing to form a Ni-Cr alloy cementation layer. CONSTITUTION:An Ni alloy contg. 1-5wt% of at least one of Si, Al and B, an Ni-Cr alloy or metallic Ni is melted and sprayed on the surface of each of steel parts used in an atmosphere causing severe corrosion at high temp. such as a boiler tube to 5-200mum thickness, and an Ni-enriched layer is formed by cementation. By chromizing the Ni-enriched layer, Cr is diffused in the layer to form a Ni-Cr alloy cementation layer having >=5mum thickness and superior corrosion resistance. |
