Method for electrochemical coating

Abstract

In a method for coating a work piece, a layer is electrochemically produced from a first material. In order to generate an inhomogeneous expansion behavior of the layer, a thermal spraying, in particular a cold gas spraying, achieves that specific zones are created in the layer from a material having a different thermal expansion behavior. These zones expand more laterally than in the direction of the layer thickness so that directed internal stresses occur in the layer upon heating or cooling of the component, which can be specifically utilized depending on the design conditions of the component.

1 - 14 . (canceled) 
     
     
         15 . A process for coating a workpiece with a layer containing a first material, comprising:
 applying zones of a second material to the workpiece, the second material having a coefficient of thermal expansion α which differs from that of the first material, the zones of the second material being applied using a thermal spraying process; and   electrochemically coating the workpiece with the first material such that after the zones of the second material are applied, each of the zones is at least partially embedded in the first material.   
     
     
         16 . The process as claimed in  claim 15 , wherein the second material has a greater coefficient of thermal expansion α than the first material. 
     
     
         17 . The process as claimed in  claim 15 , wherein cold gas spraying is employed as the thermal spraying process. 
     
     
         18 . The process as claimed in  claim 15 , wherein the layer is produced in a plurality of coats by carrying out electrochemical coating and the thermal spraying process a plurality of times. 
     
     
         19 . The process as claimed in  claim 18 , wherein thermal spraying and electrochemical coating are carried out simultaneously but each at different places on the workpiece. 
     
     
         20 . The process as claimed in  claim 19 , wherein an ionic liquid is used as an electrolyte for electrochemical coating. 
     
     
         21 . The process as claimed in  claim 15 , wherein the zones are distributed as island-like depots in a regular pattern on the workpiece. 
     
     
         22 . The process as claimed in  claim 15 , wherein the zones are arranged as strips on the workpiece. 
     
     
         23 . The process as claimed in  claim 15 , wherein the zones are arranged as rectangles in a two-dimensional array on the workpiece. 
     
     
         24 . The process as claimed in  claim 15 , wherein at least a select zone of the second material is formed on a sacrificial material which is removed to form a hollow space after production of the layer. 
     
     
         25 . The process as claimed in  claim 24 , wherein
 the hollow space forms a cantilevered bending beam,   both the first material and second material are formed on the bending beam such that the bending beam has a multilayered structure, and   one end of the bending beam is joined to a remainder of the layer.   
     
     
         26 . The process as claimed in  claim 25 , wherein the bending beam has a free end above an orifice in a surface of the workpiece. 
     
     
         27 . The process as claimed in  claim 24 , wherein
 the hollow space forms a cantilevered bending beam,   on the bending beam, the select zone is only partially embedded in the first material, such that the second material is exposed on a surface of the bending beam,   the second material has a greater coefficient of thermal expansion α than the first material,   one end of the bending beam is joined to a remainder of the layer, and   another end of the bending beam is separated at a defined spacing from the remainder of the layer.   
     
     
         28 . The process as claimed in  claim 15 , wherein
 the workpiece has an axis of rotation, and   in a circumferential direction relative to the axis of rotation, parts of the layer having zones of the second material alternate with parts of the layer not having zones of the second material.   
     
     
         29 . The process as claimed in  claim 15 , wherein each of the zones is only partially embedded in the first material such that the second material is exposed on a surface of the workpiece. 
     
     
         30 . The process as claimed in  claim 15 , wherein each of the zones is completely embedded in the first material. 
     
     
         31 . The process as claimed in  claim 15 , wherein the first material is electrochemically coated on the workpiece before and after the zones of the second material are applied.