GB2064179A - Method and Device for Protection of Metal Articles Against Chemical Metallisation - Google Patents
Method and Device for Protection of Metal Articles Against Chemical Metallisation Download PDFInfo
- Publication number
- GB2064179A GB2064179A GB8035240A GB8035240A GB2064179A GB 2064179 A GB2064179 A GB 2064179A GB 8035240 A GB8035240 A GB 8035240A GB 8035240 A GB8035240 A GB 8035240A GB 2064179 A GB2064179 A GB 2064179A
- Authority
- GB
- United Kingdom
- Prior art keywords
- metal part
- electrode
- protection
- voltage
- passivation
- 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.)
- Granted
Links
- 239000002184 metal Substances 0.000 title claims abstract description 46
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 46
- 238000001465 metallisation Methods 0.000 title claims abstract description 20
- 239000000126 substance Substances 0.000 title claims abstract description 16
- 238000000034 method Methods 0.000 title claims description 13
- 238000002161 passivation Methods 0.000 claims abstract description 11
- 230000000977 initiatory effect Effects 0.000 claims abstract description 6
- 239000008151 electrolyte solution Substances 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 7
- 229910021645 metal ion Inorganic materials 0.000 claims description 6
- 230000010349 pulsation Effects 0.000 claims description 6
- 238000012544 monitoring process Methods 0.000 claims description 2
- 239000003792 electrolyte Substances 0.000 abstract description 2
- 150000002739 metals Chemical class 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005234 chemical deposition Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1619—Apparatus for electroless plating
- C23C18/1621—Protection of inner surfaces of the apparatus
- C23C18/1623—Protection of inner surfaces of the apparatus through electrochemical processes
Landscapes
- Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
In order to prevent unintentional metallisation of metal articles in contact with electrolytes for chemical metallisation from taking place, an electrode (2) is immersed in the solution which is contacting the metal part (1) and a pulsed unipolar voltage is applied between the metal part and the electrode. This voltage possesses an amplitude exceeding a value in the phase of the polarisation curve for the metal part corresponding to initiation of passivation of the metal part. Application of the pulsed voltage is stopped when the potential difference between the electrode and the metal part which is measured in the zero intervals between pulses exceeds a given value within the range at which passivation of the metal part takes place and is only reapplied when this potential difference drops below a minimum value within the phase of the polarisation curve corresponding to initiation of passivation. <IMAGE>
Description
SPECIFICATION
Method and Device for Protection of Metal
Articles Against Chemical Metallisation
This invention relates to a method and device
for use in the protection of metals against
chemical metallisation especially nickelisation,
when in contact with solutions from which
chemical deposition of metals can occur, in
particular solutions used in chemical
metallisation.
When carrying out chemical metallisation,
certain parts of the equipment used, such as the
baths themselves generally need to undergo
protection against metallisation themselves. This
protection is frequently achieved by introducing
two electrodes, namely cathode and reference
electrode, into the metallisation solution. A
constant current is passed between the metal
parts subject to protection, and the cathode such
as to ensure that the potential of the reference
electrode lies within the plateau of the
polarization curve, at a value which corresponds
to the lowest rate of corrosion therefor and the
lowest rate of metal deposition, at the parts to be
protected, respectively.
A device is knawn for use when carrying out
such a procedure. This consists of a current
supply unit, connected to a control unit, which, in
turn, is controlled by a measuring unit,
connectable to the metal parts, subject to
protection, and to a reference electrode. The control unit supplies voltage both to the cathode
and the metal parts, subject to protection, this voltage being such that the potential at the
reference electrode is always kept at a value,
located within the plateau of the polarisation curve, that is, in a range at which passivation occurs.
The aforementioned method is such that the device which is used is costly and complex.
Moreover, there is a problem in the inadequate mechanical resistance of the passive layer on the article to be protected.
According to this invention, there is provided a method for the protection of a metal part in contact with an electrolyte solution containing metal ions from undergoing unintentional chemical metallisation, which comprises immersing an electrode in the solution and applying a unipolar pulsation voltage of zero intervals to the metal part and the electrode, which voltage possesses an amplitude exceeding a value in the phase of the polarisation curve for the metal part corresponding to initiation of passivation of the metal part, ceasing application of said voltage when the potential difference between the electrode and the metal part, being measured in the zero intervals, exceeds a given value within the range at which passivation of the metal part takes place, and monitoring said potential difference and applying said unipolar pulsation voltage when said potential difference drops below a minimum value within the phase of the polarisation curve corresponding to initiation of passivation.
This invention also provides a device for use in the protection of a metal part from undergoing unintentional chemical metallisation when in contact with an electrolyte solution containing metal ions, the device comprising an electrode to be immersed as a cathode in said solution a source of a unipolar pulsation voltage of zero intervals, means for connecting both the electrode and the metal part to said source, a potential measuring unit for measuring the potential difference between the metal part and the electrode and a control unit connected to the potential measuring unit and to a switch which lies in the supply circuit of said source.
This invention provides a method and device for protection of metals against chemical metallisation, in particular against nickelisation which involves low electric power consumption, when forming a passive layer of high mechanical resistance. The device to be used is of relatively simple design.
More particularly the method of this invention enables reduced electric power consumption to take place owing to the non-continuous current flow which occurs at the time that protection is being set up. The amount of metal deposited electrochemically onto the electrode is less than in prior art procedures, so that the exhaustion of the electrolyte used for chemical metallisation is thereby decreased. The device itself is of a simple design since it does not include any supplementary electrodes for measuring the potential. The passive layer which is obtained possesses both high thickness and high mechanical resistance. This results particularly from the fact that the current is switched off when the potential difference reaches a value corresponding to a part of the polarisation curve at which passivation occurs.
For a better understanding of the invention and to show how the same can be carried into effect reference will now be made by way of example only to the accompanying drawings, wherein:
Figure 1 is a block diagram showing the essential components of a device embodying this invention; and
Figure 2 is a circuit diagram of the device.
Referring to the drawing, the reference numberal 1 denotes metal parts, subject to protection (typically a bath for chemical metallisation as shown). An electrode 2 is immersed in an electrolyte solution in the bath to be used as in chemical metallisation. The bath 1 and electrode 2 are electrically connected both to a source 3 of unipolar voltage pulses and to a potential measuring unit 4. Unit 4 is connected to a control unit 5, which is connected in turn to a switch 6. The switch 6 is included in the supply circuit to the source of unipolar voltage pulses 3.
Optionally positioned between units 3 and 4 is a synchronisation unit 7.
The device according to the invention operates as follows: when the switch 6 is in the open position,no pulses are passed either to the metal parts which are to be subject to protection, sr to electrode 2. The unit 4 meanwhile follows the potential difference between the metal parts 1 and electrode 2. This potential difference is also followed through a signal, given by the synchronisation unit 7, which obtains information from unit 3. When this potential drops below a preliminary determined value, unit 3 receives a signal from the unit 4 and turns on the switch 6.
Unipolar voltage pulses having values between 0 and 1 OV ars passed both to the metal parts 1 subject to protection, and to the electrode 2. The pulsating voltage results in formation of a passive layer on the surface of the metal parts, thus protecting the Patter from deposition of metal. The condition of this layer affects the potential of the metal parts, subject to protection, which potential 3 measured against that of the electrode during the zero intervals. When this potential reaches a prescribed value, the potential measuring unit 4 supplies a signal to the control unit 3, which, in turn, gives command to the switch 6 for such when . The unipolar voltage pulses emitted by unit 3, may be of a square, sine or other shape.
The amplitude of these pulses should exceed the value or the po ential of the metal parts being protected, when this potential is messured against that of the electrode and when no current passes between these metal parts and electrode.
This potential corresponds to the beginning of the passivating range encompassed by the polarization curve.
Claims (7)
1. A method for the protection of a metal part in contact with an electrolyte solution containing metal ions from undergoing unintentional chemical metallisation, which comprises
immersing an electrode in the solution and applying a unipolar pulsation voltage of zero intervals to the metal part and the electrode, which voltage possesses an amplitude exceeding a value in the phase of the polarisation curve for the metal part corresponding to initiation of passivation of the metal part, ceasing application of said voltage when the potential differences between the electrode and the metal part, being measured in the zero intervals, exceeds a given value within the range at which passivation of the metal part takes place, and monitoring said potential difference and applying said unipolar pulsation voltage when said potential difference - drops below a minimum value within the phase of the polarisation curve corresponding to initiation of passivation.
2. A method as claimed in claim 1, wherein the electrolyte solution is one for nickelisation of metal articles.
3. A method as claimed in claim 1 or 2, wherein the unipolar voltage pulses have value of between 0 und 10V.
4. A method for the protection of a metal part in contact with an electrolyte solution containing metal ions from undergoing unintentional chemical metallisation, substantially as hereinbefore described with reference to the accompanying drawing.
5. A device for use in the protection of a metal part from undergoing unintentional chemical metallisation when in contact with an electrolyte solution containing metal ions, the device comprising an electrode to be immersed as a cathode in said solution, a source of a unipolar pulsation voltage of zero intervals, means for connecting both the electrode and the metal part to said source, a potential measuring unit for measuring the potential difference between the metal part and the electrode and a control unit connected to the potential measuring unit and to a switch which lies in the supply circuit of said source.
6. A device as claimed in claim 5, which additionally comprises a synchronisation unit connected between the potential measuring unit and the control unit.
7. A device for use in the protection of a metal part from undergoing unintentional chemical metallisation when in contact with an electrolyte solution containing metal ions, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BG7945377A BG30252A1 (en) | 1979-11-02 | 1979-11-02 | Method and apparatus for metal prevention of chemical metallization,especially from nickel plating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2064179A true GB2064179A (en) | 1981-06-10 |
| GB2064179B GB2064179B (en) | 1983-10-26 |
Family
ID=3906667
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8035240A Expired GB2064179B (en) | 1979-11-02 | 1980-11-03 | Method and device for protection of metal articles against chemical metallisation |
Country Status (7)
| Country | Link |
|---|---|
| BG (1) | BG30252A1 (en) |
| DD (1) | DD160836A3 (en) |
| DE (1) | DE3041129A1 (en) |
| FR (1) | FR2468657A1 (en) |
| GB (1) | GB2064179B (en) |
| IT (1) | IT1145419B (en) |
| RO (1) | RO81141A (en) |
-
1979
- 1979-11-02 BG BG7945377A patent/BG30252A1/en unknown
-
1980
- 1980-10-23 IT IT8049979A patent/IT1145419B/en active
- 1980-10-27 DD DD80224783A patent/DD160836A3/en not_active IP Right Cessation
- 1980-10-31 FR FR8023301A patent/FR2468657A1/en active Granted
- 1980-10-31 DE DE19803041129 patent/DE3041129A1/en not_active Withdrawn
- 1980-11-01 RO RO80102488A patent/RO81141A/en unknown
- 1980-11-03 GB GB8035240A patent/GB2064179B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| BG30252A1 (en) | 1981-05-15 |
| FR2468657B3 (en) | 1982-08-13 |
| DD160836A3 (en) | 1984-04-11 |
| DE3041129A1 (en) | 1981-05-14 |
| IT1145419B (en) | 1986-11-05 |
| FR2468657A1 (en) | 1981-05-08 |
| GB2064179B (en) | 1983-10-26 |
| RO81141A (en) | 1983-02-01 |
| IT8049979A0 (en) | 1980-10-23 |
| RO81141B (en) | 1983-01-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| IN164856B (en) | ||
| CA1206850A (en) | Sensor for metal coatings | |
| PT1264606E (en) | Apatite coating of metallic materials, process and use thereof | |
| GB2214520A (en) | Electrochemical processes using independently controlled voltages in alternation | |
| GB2132226A (en) | Cathodic protection of aluminium articles | |
| JP2752445B2 (en) | Epoxy resin etching method | |
| US4302316A (en) | Non-contacting technique for electroplating X-ray lithography | |
| GB2064179A (en) | Method and Device for Protection of Metal Articles Against Chemical Metallisation | |
| US3282821A (en) | Apparatus for making precision resistors | |
| Meitav et al. | Solid electrolyte interphase (SEI) electrode: Part III. Deposition-dissolution process of lithium in thionyl-chloride solution | |
| US3424660A (en) | Process for chemical plating | |
| Fukumoto et al. | Effect of connected pores on the corrosion behavior of plasma sprayed alumina coatings | |
| US3855106A (en) | Process for electrodeposition of paint | |
| US4448475A (en) | Method and apparatus for treatment of tinned metal surfaces and treated tinned metal surface | |
| Reger et al. | Interfacial phenomena at solid aluminum electrodes in solutions of AlBr3/KBr in aromatic hydrocarbons | |
| JPH04504444A (en) | Equipment for electrodepositing metal on one or both sides of a strip | |
| US3563862A (en) | High precision anodizing of thin films | |
| US3713998A (en) | Method of and apparatus for the electrochemical treatment of work surfaces | |
| US4810337A (en) | Method of treating a chromium electroplating bath which contains an alkyl sulfonic acid to prevent heavy lead dioxide scale build-up on lead or lead alloy anodes used therein | |
| JPH07157892A (en) | Electroplating method | |
| SU1544846A1 (en) | Method of electrolytic deposition of nickel coatings with titanium oxide inclusions | |
| US4840708A (en) | Process for the precise determination of the surface area of an electrically conducting shaped body | |
| US3437572A (en) | Method and apparatus for preventing ion deposition on corrosion protection electrodes | |
| Maksimović et al. | Influence of the double-layer capacity in periodically changing rate metal electrodeposition | |
| JPS63134700A (en) | Continuous electrolytic polishing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |