Method for forming corrosion-resistant plating layer and rotary machine

Abstract

An object is to provide a method for forming a superior corrosion-resistant plating layer by sealing penetrating pinholes formed in an electroless plating layer. There are provided a first plating step of performing electroless Ni—P plating on a base material ( 1 ); an etching step of etching a surface of a first plating layer ( 3 ) formed by the first plating step; and a second plating step of performing electroless Ni—P plating to form a second plating layer ( 5 ) on the first plating layer ( 3 ) processed by the etching step.

1 . A method for forming a corrosion-resistant plating layer in which a corrosion-resistant plating layer is formed on a base material by performing electroless nickel-based plating, comprising:
 a first plating step of performing electroless nickel-based plating on the base material;   an etching step of etching a surface of a first plating layer formed by the first plating step; and   a second plating step of performing electroless nickel-based plating to form a second plating layer on the first plating layer processed by the etching step.   
   
   
       2 . The method for forming a corrosion-resistant plating layer according to  claim 1 , wherein the etching step is performed using sulfuric acid. 
   
   
       3 . The method for forming a corrosion-resistant plating layer according to  claim 1 , wherein the thickness of the first plating layer is set to 5 μm or more. 
   
   
       4 . The method for forming a corrosion-resistant plating layer according to  claim 1 , wherein the thickness of the second plating layer is set to 10 μm or more. 
   
   
       5 . The method for forming a corrosion-resistant plating layer according to  claim 1 , wherein the first plating step and the second plating step are each performed by electroless Ni—P plating, and a P concentration of the electroless Ni—P plating is set in the range of 7 to 10 percent by weight. 
   
   
       6 . A rotary machine having a surface provided with a corrosion-resistant plating layer formed by the method for forming a corrosion-resistant plating layer according to  claim 1 .