Device and method for coating a component or semi-finished product with a chromium layer

Abstract

The invention relates to a device for coating a component or semi-finished product with a chromium layer, the device comprising an undivided deposition cell, in which there is an anode and which is suitable for receiving a cathodically connected component, wherein: there is an electrolyte solution containing chromium(II) in the deposition cell; the device has an electrolytic cell, which is divided by a membrane disposed in the electrolytic cell into a cathode chamber, in which there is a cathode, and an anode chamber, in which there is an anode; the cathode chamber is connected to the deposition cell by means of a line and a pump disposed in the line; the pump can pump liquid from the cathode chamber into the deposition cell and/or can pump liquid from the deposition cell into the cathode chamber.

1 . A device for coating a component ( 1 ) or a semi-finished product with a chromium layer, having an undivided deposition cell ( 3 ) in which an anode ( 2 ) is located and which is suitable for receiving a cathodically connected component ( 1 ) or semi-finished product, wherein an electrolyte solution containing chromium(II) is located in the deposition cell,
 wherein:   the device includes an electrolysis cell ( 7 ) which is divided by a membrane ( 10 ) arranged in the electrolysis cell ( 7 ) into a cathode chamber, in which a cathode ( 8 ) is located, and an anode chamber in which an anode ( 9 ) is located,   the membrane ( 10 ) is an anion exchange membrane and   the cathode chamber being connected to the deposition cell ( 3 ) via a line and a pump ( 5 ) disposed in the line, wherein the pump ( 5 ) is capable of pumping liquid from the cathode chamber into the deposition cell ( 3 ) and/or liquid from the deposition cell ( 3 ) into the cathode chamber.   
     
     
         2 . The device of  claim 1 , wherein a liquid containing chromium(III) is present in the cathode chamber. 
     
     
         3 . The device according to  claim 1 , wherein a reference electrode ( 11 ) is provided in the cathode chamber or is connected to the electrolyte solution in the cathode chamber via an electrolyte bridge. 
     
     
         4 . The device according to  claim 1 , wherein the cathode chamber is connected to the deposition cell ( 3 ) via an additional return line ( 6 ). 
     
     
         5 . The device according to  claim 1 , wherein a current source ( 4 ) in the form of a rectifier or a pulse current source or a pulse reverse current source is provided. 
     
     
         6 . A method for coating a component ( 1 ) or a semi-finished product with a chromium layer using the device according to  claim 1 , wherein,
 the component ( 1 ) or semi-finished product to be coated is immersed in the chromium(II)-containing electrolyte solution present in the deposition cell ( 3 ),   the component ( 1 ) or semi-finished product to be coated is connected cathodically and the anode ( 2 ) is connected anodically,   chromium deposition takes place in the deposition cell ( 3 ) from the liquid on the cathodically connected component ( 1 ) or semi-finished product,   the liquid present in the deposition cell ( 3 ) is pumped via the line into the cathode chamber of the electrolysis cell ( 7 ), or the liquid present in the cathode chamber is pumped via the line into the deposition cell ( 3 ).   
     
     
         7 . The method of  claim 6 , wherein the potential of a cathode located in the cathode chamber is set in the cathode chamber with the aid of a reference electrode ( 11 ) located in the cathode chamber. 
     
     
         8 . The method of  claim 6 , wherein chromium(III) ions are reduced to chromium(II) ions at the cathode ( 8 ) and thus consumed chromium(II) ions are replenished. 
     
     
         9 . The method of  claim 6 , wherein coating is carried out with direct current or coating is carried out with pulsed current or intermittent or pulsed reverse current. 
     
     
         10 . A method of use of a device for coating a component ( 1 ) or a semi-finished product with a chromium layer, wherein the device comprises:
 an undivided deposition cell ( 3 ) in which an anode ( 2 ) is located and which is suitable for receiving a cathodically connected component ( 1 ) or semi-finished product, wherein an electrolyte solution containing chromium(II) is located in the deposition cell,   an electrolysis cell ( 7 ) which is divided by a membrane ( 10 ) arranged in the electrolysis cell ( 7 ) into a cathode chamber, in which a cathode ( 8 ) is located, and an anode chamber in which an anode ( 9 ) is located,   wherein the membrane ( 10 ) is a cation exchange membrane or a diaphragm and wherein the cathode chamber being connected to the deposition cell ( 3 ) via a line and a pump ( 5 ) disposed in the line, wherein the pump ( 5 ) is capable of pumping liquid from the cathode chamber into the deposition cell ( 3 ) and/or liquid from the deposition cell ( 3 ) into the cathode chamber.