Method for producing a zinc coating optimized for coefficient of friction on a steel component

Abstract

A method for producing a zinc coating optimized for coefficient of friction on a steel component. In order to provide such a method resulting in a coating having good corrosion protection properties, good adhesion and a stable, constantly low coefficient of friction, including in the case of repeated use of the steel component, in particular multiple draft, wherein the method can be carried out both easily and cost-effectively, a zinc coating is first applied to the surface of the steel component by a galvanic deposition process and subsequently a heat treatment is carried out at a temperature of below 420° C. for the specific forming of intermetallic zinc-iron phases in the galvanically deposited zinc layer in order to optimize the coefficient of friction of the steel component.

1 . A method for producing a friction-optimized zinc coating on a steel component, having the steps of:
 applying a zinc layer to the surface of the steel component by a galvanic deposition process and subsequently   carrying out a heat treatment at a temperature of below 420° C. for the specific forming of intermetallic zinc-iron phases in the galvanically deposited zinc layer in order to optimize the friction value.   
     
     
         2 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the application of a zinc layer and all subsequent method steps for producing the zinc-coated steel component are carried out at temperatures of below 420° C. 
     
     
         3 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the holding time of the heat treatment is between 20 minutes and 10 hours, or between 20 minutes and 6 hours, or between 30 minutes and 4 hours. 
     
     
         4 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the heat treatment is carried out at a temperature between 250° C. and 310° C., whereby a ζ-phase of the iron-zinc is formed. 
     
     
         5 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the heat treatment is carried out at a temperature of between 340° C. and 360° C., whereby a δ-phase of the iron-zinc is formed. 
     
     
         6 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the surface of the steel component is pickled and/or pre-galvanized before the zinc layer is applied. 
     
     
         7 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein, before the zinc layer is applied and/or after pickling and/or after pre-galvanizing, a further heat treatment is carried out against possible hydrogen embrittlement, which is carried out at temperatures of between 200° C. and 250° C. 
     
     
         8 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein, after the zinc layer has been applied, the zinc surface is passivated by means of an organoceramic coating. 
     
     
         9 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the heat treatment for forming the zinc-iron phases takes place with the use of a temperature-resistant passivation layer following the passivation. 
     
     
         10 . The method for producing a friction-optimized zinc coating on a steel component according to  claim 1 , wherein the zinc layer is applied to the surface of the steel component in the galvanic deposition process by an alkaline zinc electrolyte containing nitrogen-containing polymers.