Device and method for electrochemically coating a workpiece

Abstract

The invention relates to an apparatus ( 1, 101, 201 ) for electrochemically coating a workpiece ( 22 ), including a coating reservoir ( 2, 102, 202 ) with a charge opening ( 5 ) and a supply reservoir ( 3, 103, 203 ), wherein the two reservoirs are in communication through a passage opening ( 4, 104, 204 ). The apparatus has at least one electrode ( 11 ) and one counter electrode ( 14 ). In order to prevent contamination of a coating liquid ( 20, 120, 220 ) during an electrochemical deposition process, the apparatus can be switched between a coating position and a rest position by rotating the supply and the coating reservoirs about at least one common axis (A, A′, A″) so that the center of gravity of the volume of the coating reservoir ( 2, 102, 202 ) in the coating position is lower in relation to the center of gravity of the volume of the supply reservoir ( 3, 103, 203 ) than in the rest position. The invention further relates to a method for coating workpieces.

1 . An apparatus for electrochemically coating a workpiece, comprising
 a coating reservoir ( 2 ,  102 ,  202 ) for receiving the workpiece ( 22 ) and   a supply reservoir ( 3 ,  103 ,  203 ) for coating liquid ( 20 ,  120 ,  220 ) communicating with the coating reservoir ( 2 ,  102 ,  202 ) through at least one passage opening ( 4 ,  104 ,  204 ) for the coating liquid ( 20 ,  120 ,  220 ),   a charge opening ( 5 ) for introducing the workpiece ( 22 ) into the coating reservoir ( 2 ,  102 ,  202 ), and   at least one electrode ( 11 ) for contacting the workpiece ( 22 ) and at least one counter electrode ( 14 ),   
       wherein the apparatus ( 1 ,  101 ,  201 ) is switchable between a coating position and a rest position by rotating the coating reservoir ( 2 ,  102 ,  202 ) and the supply reservoir ( 3 ,  103 ,  203 ) about at least one common rotation axis (A, A′, A″) in such a manner that the center of gravity of the volume of the coating reservoir ( 2 ,  102 ,  202 ) in the coating position is lower in relation to the center of gravity of the volume of the supply reservoir ( 3 ,  103 ,  203 ) than in the rest position. 
     
     
         2 . The apparatus according to  claim 1 , wherein, in the coating position and in the rest position, the coating reservoir ( 2 ,  102 ,  202 ) and the supply reservoir ( 3 ,  103 ,  203 ) are on the same side of the rotation axis (A, A′, A″) with reference to a vertical plane extending through the rotation axis (A, A′, A″). 
     
     
         3 . The apparatus according to  claim 1 , further comprising an opening ( 15 ,  215 ) for gas exchange between the coating reservoir ( 2 ,  102 ,  202 ) and the supply reservoir ( 3 ,  103 ,  203 ). 
     
     
         4 . The apparatus according to  claim 1 , further comprising a receiving device ( 7 ) arranged within the coating reservoir for the workpiece ( 22 ). 
     
     
         5 . The apparatus according to  claim 4 , wherein the receiving device ( 7 ) is rotatably supported. 
     
     
         6 . The apparatus according to  claim 1 , wherein, in the coating position, at most 50% of the volume of the supply reservoir ( 3 ,  103 ,  203 ) is below the passage opening ( 4 ,  104 ,  204 ). 
     
     
         7 . A method for coating a workpiece ( 22 ) in an apparatus ( 1 ,  101 ,  201 ) according to  claim 1 , wherein the coating reservoir ( 2 ,  102 ,  202 ) and/or the supply reservoir ( 3 ,  103 ,  203 ) are at least partially filled with a coating liquid ( 20 ,  120 ,  220 ), comprising the following steps performed in succession:
 a) introducing the workpiece ( 22 ) into the coating reservoir ( 2 ,  102 ,  202 ),   b) electrochemically depositing a coating on the workpiece ( 22 ) while the apparatus ( 1 ,  101 ,  201 ) is in the coating position,   c) switching the apparatus ( 1 ,  101 ,  201 ) into the rest position, and   d) removing the workpiece ( 22 ) from the coating reservoir ( 2 ,  102 ,  202 ).   
     
     
         8 . The method according to  claim 7 , wherein a volume of coating liquid ( 20 ,  120 ,  220 ) between 80% and 110%, of the volume of the supply reservoir ( 3 ,  103 ,  203 ) is used. 
     
     
         9 . The method according to  claim 7 , wherein an ionic liquid is used as the coating liquid ( 20 ,  120 ,  220 ) comprising ions of at least one element. 
     
     
         10 . The apparatus according to  claim 1 , wherein, in the coating position and in the rest position, the coating reservoir ( 2 ,  102 ,  202 ) and the supply reservoir ( 3 ,  103 ,  203 ) are on different sides of the rotation axis (A, A′, A″) with reference to a vertical plane extending through the rotation axis (A, A′, A″). 
     
     
         11 . The method according to  claim 7 , wherein a volume of coating liquid ( 20 ,  120 ,  220 ) between 95% and 105% of the volume of the supply reservoir ( 3 ,  103 ,  203 ) is used. 
     
     
         12 . The method according to  claim 7 , wherein a volume of coating liquid ( 20 ,  120 ,  220 ) between 99% and 101% of the volume of the supply reservoir ( 3 ,  103 ,  203 ) is used. 
     
     
         13 . The method according to  claim 9 , wherein the at least one element comprises aluminum.