Method for producing sliding member, sliding member, and substrate material of sliding member

Abstract

In a method, in which a plain bearing alloy layer is bonded to a surface of a backing steel sheet, and, a Bi-based overlay layer is then deposited on the plain bearing alloy layer by electroplating, replacement of Bi with the backing steel sheet and deposition of Bi on the backing steel sheet are prevented. Prior to the step of electroplating of the Bi-based overlay layer, the following metals and the like are formed on at least the back surface of the backing steel sheet. An electrochemically more noble metal than Bi, an electrochemically more base metal than Bi and capable of forming a passivation state, or resin.

1 . A method for producing a sliding member, comprising the steps of:
 bonding a plain bearing alloy layer to a surface of a backing steel sheet;   depositing a Bi-based overlay layer on the plain bearing alloy layer by electroplating;   prior to the step of electroplating of said Bi-based overlay layer, forming a first protecting layer consisting of an electrochemically more noble metal than Bi (hereinafter abbreviated as “noble metal”), an electrochemically more base metal than Bi and capable of forming a passivation state on a surface thereof (hereinafter abbreviated as “base metal”), or resin, on the back surface of said backing steel sheet;   passivating the surface of the first protecting layer consisting of the base metal opposite the backing steel sheet:   a backing steel sheet;   a plain bearing alloy layer bonded to the top surface side of said backing steel sheet;   an electroplated Bi-based overlay layer deposited on the top surface of the plain bearing alloy layer; and,   a first protecting layer consisting of an electrochemically more noble metal than Bi (hereinafter abbreviated as “noble metal”), an electrochemically more base metal than Bi and capable of forming a passivation state on a surface thereof (hereinafter abbreviated as “base metal”), or resin, and having a surface free of a constituent material of the following electro-plated overlay layer.   
     
     
         2 . A sliding member according to  claim 1 , characterized in that a second protecting layer formed of a noble metal or a base metal is interposed between the backing steel sheet and the plain bearing alloy layer. 
     
     
         3 . A sliding member according to  claim 1 , wherein it is mounted in an actual machine. 
     
     
         4 . A method according to  claim 3 , wherein the actual machine is an engine. 
     
     
         5 . A sliding member according to  claim 1 , further comprising a second protecting layer consisting of the noble metal or base metal on the top surface of the backing steel sheet. 
     
     
         6 . A sliding member according to  claim 1 , wherein the noble metal is Cu and the base metal is selected from a group consisting of Cr, Ni and Al. 
     
     
         7 . A sliding member according to  claim 3 , wherein the first protecting layer consists of the base metal and the back surface of the first protecting layer is passivated. 
     
     
         8 . A sliding member according to  claim 7 , wherein thickness of the first protecting layer is from 0.2 to 10 μm.