CA1112205A - Method of and apparatus for electrochemically processing metallic surfaces - Google Patents
Method of and apparatus for electrochemically processing metallic surfacesInfo
- Publication number
- CA1112205A CA1112205A CA285,074A CA285074A CA1112205A CA 1112205 A CA1112205 A CA 1112205A CA 285074 A CA285074 A CA 285074A CA 1112205 A CA1112205 A CA 1112205A
- Authority
- CA
- Canada
- Prior art keywords
- electrolyte
- electrolytic cell
- chamber
- electrically conductive
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/07—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process being removed electrolytically
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F3/00—Electrolytic etching or polishing
- C25F3/02—Etching
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F7/00—Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects; Servicing or operating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/09—Treatments involving charged particles
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Electrolytic Production Of Metals (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Abstract of the Disclosure A method of electrochemically processing metallic surfaces of workpieces arranged in a contact-free manner with regard to the cathode and anode of an electrolytic cell by means of an electrolyte. For the purpose of transferring an electric charge onto the workpiece surface to be pro-cessed, the electrolyte contains suspended electrically conductive bodies.
These electrically conductive bodies are charged in a first chamber of the cell that contains the electrode the polarity of which determines the pro-cessing (oxidative or reductive treatment) of the workpiece surface. A
shielding diaphragm or ion exchange membrane prevents the electrically con-ductive bodies from discharging on the counter-electrode, the electrolyte being positively circulated in a circuit between the charging electrode and the workpiece to be processed. Outside the electrolytic cell, after separation of the suspended electrically conductive bodies, electrolyte is withdrawn from the circuit, and is introduced into the second chamber of electrolytic cell that contains the counter-electrode shielded by the diaphragm. A conveying line for the electrolyte containing the electrically conductive bodies extends between the first chamber of the electrolytic cell and the treatment chamber. One portion of said conveying line outside the electrolytic cell comprises a porous wall which is permeable to the electro-lyte but retains the electrically conductive bodies. An annular chamber formed between the porous wall and a surrounding outer pipe communicates with the second chamber (containing the counter-electrode) in the electrolytic cell for exchanging electrolyte.
These electrically conductive bodies are charged in a first chamber of the cell that contains the electrode the polarity of which determines the pro-cessing (oxidative or reductive treatment) of the workpiece surface. A
shielding diaphragm or ion exchange membrane prevents the electrically con-ductive bodies from discharging on the counter-electrode, the electrolyte being positively circulated in a circuit between the charging electrode and the workpiece to be processed. Outside the electrolytic cell, after separation of the suspended electrically conductive bodies, electrolyte is withdrawn from the circuit, and is introduced into the second chamber of electrolytic cell that contains the counter-electrode shielded by the diaphragm. A conveying line for the electrolyte containing the electrically conductive bodies extends between the first chamber of the electrolytic cell and the treatment chamber. One portion of said conveying line outside the electrolytic cell comprises a porous wall which is permeable to the electro-lyte but retains the electrically conductive bodies. An annular chamber formed between the porous wall and a surrounding outer pipe communicates with the second chamber (containing the counter-electrode) in the electrolytic cell for exchanging electrolyte.
Description
z:~
The present invention relates to a method o~ and apparatus for electrochemically processing metallic surfaces of ~orkpieces arrangecl in a contact-ree manner with regard to the ca~hode and anode, by means of an elec-trolyte which, for purposes of transferring an electric charge to the surface to be processed, cvntains electrically conductive bodies which are suspended in the electrolyte and wh;ch are charged in an electrolytic cell on ~he elec-trode which determines the processing of said surface, and which are protected against a dischar~e on the coun~er elec~Tode of ~he electroly~ic cell by a s ~ . lJ;r~
. ~~ diaphragm skiol~ivg or an ion exchange membranelsaid counter electrode, said electrolyte being positively conveyed between ~he elec~rode charging said ; electrically conduct;ve bodies on one hand and the surface of the workpieces to be processed on the other hand.
Printed circuits are produced in conformity with thîs method. To this end, one or both sides of plates of electrically non-conductive syn~hetic material are copper coated. Those metal surfaces which are intended to ~orm the desired circuit are covered by a protective layer while the remaining portion of ~he copper coating is removed from said plates of synthetic material.
The electrically conductive bodies whi~h are suspended in the electrolyte are positively charged on the anode of an electrolytic cell, and subsequently are brought into contact with the sur~ace of the copper layer. Metal ions enter into solution ~Ihich ions are deposited on the cathode of the electrolykic cell.
This method is also employed for making metallic form parts with which parti-cular precision and contour sharpness is a foremost requirement, as is also the case with flow conducting elements such as turbine blades or nozzles. The ; direct recovery of the remo~ed metals as it is possible in this method -- which metals deposit on the counter electrode -- leads to an econo~ic and at the same time ecologically favorable method. This ad~antage of the method is in particular also used when recovering metals from so-called cable scrap.
From this method described in United States Patent 3,97~,0so l)ioisok et al issued August 10, 1976 it is known to fced thc clectrolytc containing the electrically conductive bodies, between the electrode which charges sald bodies on one hand and the surface of the workpieces to be processed on the other hand, and to do this by rotating the electrode, or by the employment of circulating pumps. The electrolyte passes from the interior of the electro-lytic cell in which the electrically conductive bodies are charged on the electrode determining the processing of said surface, through the diaphragm into the region of the counter electrode. ~ drawback of this method is that in the course of the operation electrically conductive bodies are deposited on the diaphragm so that consequently the exchange of electrolyte between cathode chamber and anode chamber (which exchange is necessary for the electrolytic processing operation) is gradually reduced. When removing metal from metallic surfaces, due to the reduction in metal ions within the region of the cathode, there exists the danger that undesired hydrogen gener-ation will occur in the cathode chamber. A further disadvantage of this method is that during the operation, the cell voltage and thus the energy consumption required for the processing operation gradually increases, and at the same time a reduction occurs on the electrically conductive bodies in the electrolyte which transfer the charge sn that the processing time necessary for the partial removal of the surface increases.
The present invention provides a method of electrochemically pro-cessing metallic surfaces of workpieces arranged in a contact-free manner relative to the electrodes of an electrolytic cell by means of an electrolyte containing electrically conductive bodies suspended in said electrolyte, which method includes the steps of: charging said electrically conductive bodies in said electrolytic cell on one electrode, which determines the polarity of the workpiece surface to be processed, while shielding the other electrode against discharge thereon of said electrically conductive bodies, and while positively circulating said electrolyte in a circuit between the said one electrode and the workpiece to be processed, withdrawing electrolyte from said circuit outside sald electrolytlc cell after separ~tLon of sald electrically conductive bodies suspended in the electrolyte, and lntrocluclng electrolyte from outside sald electro]ytlc cell into the shlelded reg:Lon con-.
s taining said other electrode of said electrolytic cell.
From another aspect, the invention provides an installation for electrochemically processing metallic surfaces of workpieces, including:
; an electrolytic cell provided with a diaphragm inserted between anode and cathode electrodes, the diaphragm being adapted to divide the cell into first and second chambers; said first chamber, which includes a first of said electrodes the polarity of which determines the polarity of the work-piece, containing conductive bodies suspended in an electrolyte so that said bodies are charged by contact with said electrode; and said second chamber including the other electrode and containing electrolyte free of said ~ ;
suspended conductive bodies;
a treatment chamber wherein to dispose, free from contact with anode and cathode, workpieces the surfaces of which are to be contacted with the electrolyte containing the electrically conductive bodies after charging of said bodies at said first electrode;
a conveying path for the electrolyte containing the bodies being provided between the treatment chamber and said first chamber, one part of the conveying path being provided with a porous wall which is permeable to the electrolyte but retains the electrically conductive bodies; and means for conducting electrolyte, permeating without said bodies through said porous wall, into said second chamber of the electrolytic cell for exchanging electrolyte therewith.
Objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which: ;
Figure 1 diagrammatically shows by way of example one installation for practicing the method of the invention.
Figure 2 is a diagrammatical vertical section of the installation according to Figure 1, said section being taken along the llne II-II of Figure 1.
According to the method of the present inventlon for electrochemic-?q,~
ally processing metallic surfaces o~ workpieces arranged in a contact-free manner with regard to the cathode and anode, the elec~rolyte is pos:itively cir-culated in a circult between the electrode charging said workpieces and the sur~ace of the workpieces to be processed, and electrolyte pro~ided outside the electr~ly~ic C911 after s~paration o the el~ctrically conductive bodies suspended in the ~lectrolyte, is withdrawn from said circuit and is in~roduced in~o the electrolytic cell within ~he region of the counter electrode shielded by the diaphragm.
Referring now to the drawing in detail, the apparatus according to the invention includes an electrolytic cell 1 with an anode 2 and a cathode 3.
Interposed between these electrodes o the elec~rolytic cell 1 is a diaphragm or an ion exchange membrane 4 which divides the electrolytic cell into two chambers 5 and 6. In the chamber 5 which houses the anode 2, there are elec-trically conductive bodies which are suspended in ~he electrolyte and which are electrically charged on the anode 2. The electrically conductive bodies are prevented from passing from chamber 5 into chamber 6 of the electrolytic cell 1 in which ~he cathode 3 is arranged by means of said inser~ed diaphragm 4.
~rom the chamber 5 of the electrolytic cell 1 electrolyte with ano-dically charged electrically conductive bodies is passes into a conveying i` line 8 by a conveying means 7, in the speciic example by a Y~ *~ pump P.
The conveying line 8 leads in~o a processing chamber 9. At the end of ~he conveying line 8, nozzle spray heads 10 are arranged, through which the elec-trolyte is sprayed onto the sur~ace of a workpiece 11 to be processed> ~he workpiece being transported for the electrolytic treatment from the position shown in Figure 1 on the left hand side of the nozzle spray heads 10 to be-tween the nozzle spray heads, Instead of spraying the electrolyte containing the charged bodies onto the surface of the workpieces to be processed, it is also possible to immerse the workpieces into an olectrolytic bath. ~xpodiently, this is done for instance when recovering metals from so~called cable scrap.
~?,,~
In the p~ocessing or treatment chamber 9, ~he anodically charged el0ctrically conductive bodies give off their charge to the surface ~o be processed while ions corresponding to the electrochemical charge equivalent en~er in~o solution in the electrolyte. With the processing of workpieces having a copper surface as is assumed in the paFticular embodiment shown, copper cations en~er into solution.
From ~he processing chamber 9, ~he electrolyte containing ~he dis-~) qve ~ o ~ ~
B charged electrically conductive bodies and the cations which w4*~ into solution,flows hack into ~he chamber 5 of the electrolytic cell 1, where the elec~ric-ally conductive bodies suspended in the electroly~e are charged again on the anode 2. 'rhe electroly~e is re-circulated and conveyed ~o the processing chamber 9.
Qn the pressure side of the pump 7, in the conveying line 8 there is a saction 12 ~hich has a porous wall. In ~he specific embodiment shown, the section 12 of the conveying line 8 consists of a grzphite pipe 13 through which the electroly~e solution passes which contains ~he electrically conduc-tive bodies, The graphite pipe 13 is surrou~lded by a mantle 14 so that be-tween the graphite pipe 13 and the mantle 14 there is an annular chamber into which electrolyte free from electrically conductive bcdies can pass ~hrough the porous wall of the section 12. This annular chamber communicates through a pipeline 15 with the chamber 6 of the electrolytic cell 1 in wh;ch the cathode 3 is arranged~ In this way, on the cathode 3 a uni~orm metal ion concentration is assured, and the development of hydrogen on ths cathode is prevented. At the same time, the cell voltage in the electrolytic cell 1 remains constant.
Due to the feed in o electrolyte into the chamber 6 of the cathode 3, an o~erpressure is created so that electroly~e ~lows through the diaphragm 4 into the chamber 5 o~ the e~ectrolytic cell 1. In this way, the diaphragm is rinsed, and electrically conductive bodies which mlght have deposited there-on ~ill be ~a~hed o~ the diaphragm. When an ion exchange membrane is used - 5 ~
(instead of a diaphragm) the electrolyte flows hack into the chamber S ~hrough a connection tube 20 or through a conveying line 16.
To the space surrounding the section 12 with a porous wall there is connected a further conveying line 16 which leads in~o a r~nsing chamber 17 for the workpieces to be ~reated in the processing chamber 9. In the drawing, the workpieces present in the rinisng chamber 17 are designated with the reference nu~eral lla. During the rinsing operation with the electrolyte, the processed surfaces of ~he workpieces are cleaned of adherlng electrically conductive bodies. From the rinsing chamber 17, ~he electrolyte flows back directly into the chamber 5 o~ the electrolytic cell 1.
In the specific embodiment shown in the drawing, the rinsing chamber 17 is followed by a further rinsing chamber 18 in which the ~reated workpieces which in Figure 1 are designated with the reference ~u~eral llb are freed from the residual still adhering electrolyte by means of clear water. The water is conveyed into the rinsing chamber 18 by a pump 19.
Exa~ple:
Por processing copper covered plates, graphite powder particles of a size of up ~o 0.1 mm were added to an ammoniacal electrolyte which contained a coppar salt contalning up to 100 grams copper per liter. As graphite pipe of commerc~ally available por~us graphite ~here was installed a pipa with an inner diameter of 40 mm, a wall thickness of 5 mm and a length of 1000 mm.
In the apparatus, approximately S0 liters per minute of electrolyte was cir-culated. Of this quantity of electrolyte, per minute approximately from 400 to 500 cubic centimeters of electrolyte free from electrically conductive bodies were withdrawn from the annular space surrounding the graphite pipe 13 while of this quanti~y about 60% were introduced into the cathode space whereas the rest was employed ~or rinsing the processed or treated surface of the workpieces, In the apparatus during the period of operation, the necessary cell voltage remained constant in the electrolytic cell at 1.8 V
3Q ~ith20 A current ~low~ Also the diaphragm 4 romalned well pormoable.
S
It is, of course, to be und~rstood tha~ ~he present invention is, by no means, limited to the specific showing in the drawing or the specific example set orth above, but also comprises any modifica~ions within the scope of the appended claims.
The present invention relates to a method o~ and apparatus for electrochemically processing metallic surfaces of ~orkpieces arrangecl in a contact-ree manner with regard to the ca~hode and anode, by means of an elec-trolyte which, for purposes of transferring an electric charge to the surface to be processed, cvntains electrically conductive bodies which are suspended in the electrolyte and wh;ch are charged in an electrolytic cell on ~he elec-trode which determines the processing of said surface, and which are protected against a dischar~e on the coun~er elec~Tode of ~he electroly~ic cell by a s ~ . lJ;r~
. ~~ diaphragm skiol~ivg or an ion exchange membranelsaid counter electrode, said electrolyte being positively conveyed between ~he elec~rode charging said ; electrically conduct;ve bodies on one hand and the surface of the workpieces to be processed on the other hand.
Printed circuits are produced in conformity with thîs method. To this end, one or both sides of plates of electrically non-conductive syn~hetic material are copper coated. Those metal surfaces which are intended to ~orm the desired circuit are covered by a protective layer while the remaining portion of ~he copper coating is removed from said plates of synthetic material.
The electrically conductive bodies whi~h are suspended in the electrolyte are positively charged on the anode of an electrolytic cell, and subsequently are brought into contact with the sur~ace of the copper layer. Metal ions enter into solution ~Ihich ions are deposited on the cathode of the electrolykic cell.
This method is also employed for making metallic form parts with which parti-cular precision and contour sharpness is a foremost requirement, as is also the case with flow conducting elements such as turbine blades or nozzles. The ; direct recovery of the remo~ed metals as it is possible in this method -- which metals deposit on the counter electrode -- leads to an econo~ic and at the same time ecologically favorable method. This ad~antage of the method is in particular also used when recovering metals from so-called cable scrap.
From this method described in United States Patent 3,97~,0so l)ioisok et al issued August 10, 1976 it is known to fced thc clectrolytc containing the electrically conductive bodies, between the electrode which charges sald bodies on one hand and the surface of the workpieces to be processed on the other hand, and to do this by rotating the electrode, or by the employment of circulating pumps. The electrolyte passes from the interior of the electro-lytic cell in which the electrically conductive bodies are charged on the electrode determining the processing of said surface, through the diaphragm into the region of the counter electrode. ~ drawback of this method is that in the course of the operation electrically conductive bodies are deposited on the diaphragm so that consequently the exchange of electrolyte between cathode chamber and anode chamber (which exchange is necessary for the electrolytic processing operation) is gradually reduced. When removing metal from metallic surfaces, due to the reduction in metal ions within the region of the cathode, there exists the danger that undesired hydrogen gener-ation will occur in the cathode chamber. A further disadvantage of this method is that during the operation, the cell voltage and thus the energy consumption required for the processing operation gradually increases, and at the same time a reduction occurs on the electrically conductive bodies in the electrolyte which transfer the charge sn that the processing time necessary for the partial removal of the surface increases.
The present invention provides a method of electrochemically pro-cessing metallic surfaces of workpieces arranged in a contact-free manner relative to the electrodes of an electrolytic cell by means of an electrolyte containing electrically conductive bodies suspended in said electrolyte, which method includes the steps of: charging said electrically conductive bodies in said electrolytic cell on one electrode, which determines the polarity of the workpiece surface to be processed, while shielding the other electrode against discharge thereon of said electrically conductive bodies, and while positively circulating said electrolyte in a circuit between the said one electrode and the workpiece to be processed, withdrawing electrolyte from said circuit outside sald electrolytlc cell after separ~tLon of sald electrically conductive bodies suspended in the electrolyte, and lntrocluclng electrolyte from outside sald electro]ytlc cell into the shlelded reg:Lon con-.
s taining said other electrode of said electrolytic cell.
From another aspect, the invention provides an installation for electrochemically processing metallic surfaces of workpieces, including:
; an electrolytic cell provided with a diaphragm inserted between anode and cathode electrodes, the diaphragm being adapted to divide the cell into first and second chambers; said first chamber, which includes a first of said electrodes the polarity of which determines the polarity of the work-piece, containing conductive bodies suspended in an electrolyte so that said bodies are charged by contact with said electrode; and said second chamber including the other electrode and containing electrolyte free of said ~ ;
suspended conductive bodies;
a treatment chamber wherein to dispose, free from contact with anode and cathode, workpieces the surfaces of which are to be contacted with the electrolyte containing the electrically conductive bodies after charging of said bodies at said first electrode;
a conveying path for the electrolyte containing the bodies being provided between the treatment chamber and said first chamber, one part of the conveying path being provided with a porous wall which is permeable to the electrolyte but retains the electrically conductive bodies; and means for conducting electrolyte, permeating without said bodies through said porous wall, into said second chamber of the electrolytic cell for exchanging electrolyte therewith.
Objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which: ;
Figure 1 diagrammatically shows by way of example one installation for practicing the method of the invention.
Figure 2 is a diagrammatical vertical section of the installation according to Figure 1, said section being taken along the llne II-II of Figure 1.
According to the method of the present inventlon for electrochemic-?q,~
ally processing metallic surfaces o~ workpieces arranged in a contact-free manner with regard to the cathode and anode, the elec~rolyte is pos:itively cir-culated in a circult between the electrode charging said workpieces and the sur~ace of the workpieces to be processed, and electrolyte pro~ided outside the electr~ly~ic C911 after s~paration o the el~ctrically conductive bodies suspended in the ~lectrolyte, is withdrawn from said circuit and is in~roduced in~o the electrolytic cell within ~he region of the counter electrode shielded by the diaphragm.
Referring now to the drawing in detail, the apparatus according to the invention includes an electrolytic cell 1 with an anode 2 and a cathode 3.
Interposed between these electrodes o the elec~rolytic cell 1 is a diaphragm or an ion exchange membrane 4 which divides the electrolytic cell into two chambers 5 and 6. In the chamber 5 which houses the anode 2, there are elec-trically conductive bodies which are suspended in ~he electrolyte and which are electrically charged on the anode 2. The electrically conductive bodies are prevented from passing from chamber 5 into chamber 6 of the electrolytic cell 1 in which ~he cathode 3 is arranged by means of said inser~ed diaphragm 4.
~rom the chamber 5 of the electrolytic cell 1 electrolyte with ano-dically charged electrically conductive bodies is passes into a conveying i` line 8 by a conveying means 7, in the speciic example by a Y~ *~ pump P.
The conveying line 8 leads in~o a processing chamber 9. At the end of ~he conveying line 8, nozzle spray heads 10 are arranged, through which the elec-trolyte is sprayed onto the sur~ace of a workpiece 11 to be processed> ~he workpiece being transported for the electrolytic treatment from the position shown in Figure 1 on the left hand side of the nozzle spray heads 10 to be-tween the nozzle spray heads, Instead of spraying the electrolyte containing the charged bodies onto the surface of the workpieces to be processed, it is also possible to immerse the workpieces into an olectrolytic bath. ~xpodiently, this is done for instance when recovering metals from so~called cable scrap.
~?,,~
In the p~ocessing or treatment chamber 9, ~he anodically charged el0ctrically conductive bodies give off their charge to the surface ~o be processed while ions corresponding to the electrochemical charge equivalent en~er in~o solution in the electrolyte. With the processing of workpieces having a copper surface as is assumed in the paFticular embodiment shown, copper cations en~er into solution.
From ~he processing chamber 9, ~he electrolyte containing ~he dis-~) qve ~ o ~ ~
B charged electrically conductive bodies and the cations which w4*~ into solution,flows hack into ~he chamber 5 of the electrolytic cell 1, where the elec~ric-ally conductive bodies suspended in the electroly~e are charged again on the anode 2. 'rhe electroly~e is re-circulated and conveyed ~o the processing chamber 9.
Qn the pressure side of the pump 7, in the conveying line 8 there is a saction 12 ~hich has a porous wall. In ~he specific embodiment shown, the section 12 of the conveying line 8 consists of a grzphite pipe 13 through which the electroly~e solution passes which contains ~he electrically conduc-tive bodies, The graphite pipe 13 is surrou~lded by a mantle 14 so that be-tween the graphite pipe 13 and the mantle 14 there is an annular chamber into which electrolyte free from electrically conductive bcdies can pass ~hrough the porous wall of the section 12. This annular chamber communicates through a pipeline 15 with the chamber 6 of the electrolytic cell 1 in wh;ch the cathode 3 is arranged~ In this way, on the cathode 3 a uni~orm metal ion concentration is assured, and the development of hydrogen on ths cathode is prevented. At the same time, the cell voltage in the electrolytic cell 1 remains constant.
Due to the feed in o electrolyte into the chamber 6 of the cathode 3, an o~erpressure is created so that electroly~e ~lows through the diaphragm 4 into the chamber 5 o~ the e~ectrolytic cell 1. In this way, the diaphragm is rinsed, and electrically conductive bodies which mlght have deposited there-on ~ill be ~a~hed o~ the diaphragm. When an ion exchange membrane is used - 5 ~
(instead of a diaphragm) the electrolyte flows hack into the chamber S ~hrough a connection tube 20 or through a conveying line 16.
To the space surrounding the section 12 with a porous wall there is connected a further conveying line 16 which leads in~o a r~nsing chamber 17 for the workpieces to be ~reated in the processing chamber 9. In the drawing, the workpieces present in the rinisng chamber 17 are designated with the reference nu~eral lla. During the rinsing operation with the electrolyte, the processed surfaces of ~he workpieces are cleaned of adherlng electrically conductive bodies. From the rinsing chamber 17, ~he electrolyte flows back directly into the chamber 5 o~ the electrolytic cell 1.
In the specific embodiment shown in the drawing, the rinsing chamber 17 is followed by a further rinsing chamber 18 in which the ~reated workpieces which in Figure 1 are designated with the reference ~u~eral llb are freed from the residual still adhering electrolyte by means of clear water. The water is conveyed into the rinsing chamber 18 by a pump 19.
Exa~ple:
Por processing copper covered plates, graphite powder particles of a size of up ~o 0.1 mm were added to an ammoniacal electrolyte which contained a coppar salt contalning up to 100 grams copper per liter. As graphite pipe of commerc~ally available por~us graphite ~here was installed a pipa with an inner diameter of 40 mm, a wall thickness of 5 mm and a length of 1000 mm.
In the apparatus, approximately S0 liters per minute of electrolyte was cir-culated. Of this quantity of electrolyte, per minute approximately from 400 to 500 cubic centimeters of electrolyte free from electrically conductive bodies were withdrawn from the annular space surrounding the graphite pipe 13 while of this quanti~y about 60% were introduced into the cathode space whereas the rest was employed ~or rinsing the processed or treated surface of the workpieces, In the apparatus during the period of operation, the necessary cell voltage remained constant in the electrolytic cell at 1.8 V
3Q ~ith20 A current ~low~ Also the diaphragm 4 romalned well pormoable.
S
It is, of course, to be und~rstood tha~ ~he present invention is, by no means, limited to the specific showing in the drawing or the specific example set orth above, but also comprises any modifica~ions within the scope of the appended claims.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of electrochemically processing metallic surfaces of workpieces arranged in a contact-free manner relative to the electrodes of an electrolytic cell by means of an electrolyte containing electrically conductive bodies suspended in said electrolyte, which method includes the steps of: charging said electrically conductive bodies in said electrolytic cell on one electrode, which determines the polarity of the workpiece surface to be processed, while shielding the other electrode against discharge there-on of said electrically conductive bodies, and while positively circulating said electrolyte in a circuit between the said one electrode and the work-piece to be processed, withdrawing electrolyte from said circuit outside said electrolytic cell after separation of said electrically conductive bodies suspended in the electrolyte, and introducing electrolyte from outside said electrolytic cell into the shielded region containing said other electrode of said electrolytic cell.
2. A method according to claim 1, which includes the step of maintain-ing a higher pressure in the shielded region of the counter electrode in the electrolytic cell than within the region containing said one electrode for charging the electrically conductive bodies.
3. An installation for electrochemically processing metallic surfaces of workpieces, including:
an electrolytic cell provided with a diaphragm inserted between anode and cathode electrodes, the diaphragm being adapted to divide the cell into first and second chambers; said first chamber, which includes a first of said electrodes the polarity of which determines the polarity of the work-piece, containing conductive bodies suspended in an electrolyte so that said bodies are charged by contact with said electrode; and said second chamber including the other electrode and containing electrolyte free of said suspended conductive bodies;
a treatment chamber wherein to dispose, free from contact with anode and cathode, workpieces the surfaces of which are to be contacted with the electrolyte containing the electrically conductive bodies after charging of said bodies at said first electrode;
a conveying path for the electrolyte containing the bodies being provided between the treatment chamber and said first chamber, one part of the conveying path being provided with a porous wall which is permeable to the electrolyte but retains the electrically conductive bodies; and means for conducting electrolyte, permeating without said bodies through said porous wall, into said second chamber of the electrolytic cell for exchanging electrolyte therewith.
an electrolytic cell provided with a diaphragm inserted between anode and cathode electrodes, the diaphragm being adapted to divide the cell into first and second chambers; said first chamber, which includes a first of said electrodes the polarity of which determines the polarity of the work-piece, containing conductive bodies suspended in an electrolyte so that said bodies are charged by contact with said electrode; and said second chamber including the other electrode and containing electrolyte free of said suspended conductive bodies;
a treatment chamber wherein to dispose, free from contact with anode and cathode, workpieces the surfaces of which are to be contacted with the electrolyte containing the electrically conductive bodies after charging of said bodies at said first electrode;
a conveying path for the electrolyte containing the bodies being provided between the treatment chamber and said first chamber, one part of the conveying path being provided with a porous wall which is permeable to the electrolyte but retains the electrically conductive bodies; and means for conducting electrolyte, permeating without said bodies through said porous wall, into said second chamber of the electrolytic cell for exchanging electrolyte therewith.
4. An installation according to claim 3, characterized in that said one part of the conveying path is connected with the pressure side of a conveying means for the electrolyte containing electrically conductive bodies.
5. An installation according to either claim 3 or 4, characterized in that said part of the conveying path having a porous wall is made from graphite.
6. An installation according to either claim 3 or 4, characterized in that the free cross-section of said one part of the conveying path having the porous wall is dimensioned so as to provide a flow rate of a magnitude sufficiently high to prevent any of the bodies suspended in the electrolyte being deposited on the porous wall.
7. An installation according to claim 3 or 4, characterized in that at the outlet end of the treatment chamber there is provided a rinsing chamber for the treated workpieces, into which is connected a conveying line which delivers electrolyte from the space surrounding the porous wall of the convey-ing path.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2637745A DE2637745B1 (en) | 1976-08-21 | 1976-08-21 | Process for the electrochemical processing of metallic surfaces |
| DEP2637745.7 | 1976-08-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1112205A true CA1112205A (en) | 1981-11-10 |
Family
ID=5986042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA285,074A Expired CA1112205A (en) | 1976-08-21 | 1977-08-19 | Method of and apparatus for electrochemically processing metallic surfaces |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1112205A (en) |
| DE (1) | DE2637745B1 (en) |
-
1976
- 1976-08-21 DE DE2637745A patent/DE2637745B1/en active Granted
-
1977
- 1977-08-19 CA CA285,074A patent/CA1112205A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2637745C2 (en) | 1978-08-24 |
| DE2637745B1 (en) | 1977-12-08 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |