CA2059735A1 - Electrode and method for measuring levelling power - Google Patents
Electrode and method for measuring levelling powerInfo
- Publication number
- CA2059735A1 CA2059735A1 CA 2059735 CA2059735A CA2059735A1 CA 2059735 A1 CA2059735 A1 CA 2059735A1 CA 2059735 CA2059735 CA 2059735 CA 2059735 A CA2059735 A CA 2059735A CA 2059735 A1 CA2059735 A1 CA 2059735A1
- Authority
- CA
- Canada
- Prior art keywords
- cathode
- electrolyte
- region
- peak
- current
- 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.)
- Abandoned
Links
Landscapes
- Electrolytic Production Of Metals (AREA)
Abstract
ELECTRODE AND METHOD FOR MEASURING LEVELLING POWER
ABSTRACT
The invention provides an apparatus and method for determining levelling power of an electrolyte. An anode and cathode are immersed in the electrolyte. The cathode has a plating surface for electrodeposition of a metal from the electrolyte. The plating surface has a peak region and a base region separated and electrically isolated by an insulator. The peak region has a greater tendency toelectrodeposit the metal per unit surface area than the base region. The anode and cathode are placed in a test cell or suspended in a commercial electrodeposition cell.
A means for applying current between said anode and said cathode is used for causing the metal from the electrolyte to electrodeposit on the plating surface of the cathode.
The current from plating on the peak region and the base region are measured separately to determine levelling power of an electrolyte.
ABSTRACT
The invention provides an apparatus and method for determining levelling power of an electrolyte. An anode and cathode are immersed in the electrolyte. The cathode has a plating surface for electrodeposition of a metal from the electrolyte. The plating surface has a peak region and a base region separated and electrically isolated by an insulator. The peak region has a greater tendency toelectrodeposit the metal per unit surface area than the base region. The anode and cathode are placed in a test cell or suspended in a commercial electrodeposition cell.
A means for applying current between said anode and said cathode is used for causing the metal from the electrolyte to electrodeposit on the plating surface of the cathode.
The current from plating on the peak region and the base region are measured separately to determine levelling power of an electrolyte.
Description
20~973~
ELECTkODE AND METHOD FOR MF~SURING LEVELLING POWER
FIELD OF INVENI`ION
This invention is related to the field of measuring the ability of addition agents to prevent formation of rough and poraus surfaces and nodules during S electrodeposition.
BACKGROUND OF THE ART AND PRO~3LEM
, The process of electrodeposition is widely used commercially in processes such as electrorefining, electrowinning and electroplating. In commercia}
electrodeposition operations organic and/or inorganic addition agents are addcd 10 directly to electrolytic solutions. The addition agents control uniformity of metal deposition on a cathode. When the addition agents are out of balance for proper electrodeposition, the metal deposit forms rough porous surfaces and nodules which encapsulate impurities contained in the electrolyte. Improper deposition typically greatly reduces the value of the product due to isnpurities mechanically imbedcle(i in 15 the rough cathode surface.
:, .
~ ~ , ' ' ,. :
ELECTkODE AND METHOD FOR MF~SURING LEVELLING POWER
FIELD OF INVENI`ION
This invention is related to the field of measuring the ability of addition agents to prevent formation of rough and poraus surfaces and nodules during S electrodeposition.
BACKGROUND OF THE ART AND PRO~3LEM
, The process of electrodeposition is widely used commercially in processes such as electrorefining, electrowinning and electroplating. In commercia}
electrodeposition operations organic and/or inorganic addition agents are addcd 10 directly to electrolytic solutions. The addition agents control uniformity of metal deposition on a cathode. When the addition agents are out of balance for proper electrodeposition, the metal deposit forms rough porous surfaces and nodules which encapsulate impurities contained in the electrolyte. Improper deposition typically greatly reduces the value of the product due to isnpurities mechanically imbedcle(i in 15 the rough cathode surface.
:, .
~ ~ , ' ' ,. :
-2- 2~973~ PC-4102 Copper electrorefineries around the world typically use a combination oE
several addition agents to control electrorefining. Addition agents used Çor electroreEining include animal glue, thiourea, lignin sulfonate, alkyl sulEonate and chloride ion. Positively charged addition agents such as animal glue are drawn by 5 electrochernical Eorces to the negatively charged cathode. Positively charged addition agents are more strongly attracted to increased current density regions of peaks or nodules forrned on a cathode. The increased concentration of addition agents on peaks or nodules slows down the metal electrodeposition and levelling takes place.
Advantageously, an addition agent such as glue is preferentially a(lsorbed 10 on the peak or nodule to form a resistance layer which locally increases over-potential and levelling on the cathode surface takes place. IE excess addition agent is present, the addition agent adsorbs over an entire cathode surface which causes a loss oflevelling eEfect. If insufEicient addition agent is present, growth on peaks and nodules is not prevented and the peaks and nodules grow in an uncontrolled accelerated 15 manner. Typical optimum concentration of addition agents is in the parts per million range. Unfortunately, concentrations of addition agents are very difficult to measure in a simple and accurate manner. ~urthermore, several addition agents break downinto multiple components and eventually lose levelling effect.
Typical copper electrorefinery addition agent systerns are complicated 20 and include a combination of three or more addition agents. As a result oE high interactions between addition agents, levelling effects of new combinations of levelling agents are unpredictable. To evaluate an addition agent system time consuming laboratory or pilot plating experiments have been required. A typical experimentrequires 7 to 14 days to complete. It would require about 5 to 10 years (without25 simultaneous experiments) to investigate every combination of a system of four addition agents each at Eour different concentrations.
Several techniques have been developed to monitor addition agent concentrations in electrolyte. Langner et al, in U.S. Patent No. 4,834,842 describe a techniquc oE measuring efEectiveness of addition agents by measuring kinetics oE30 cathode polarization under predetermined conditions. Other techniques described in the literature have measured cathode polarization in an attempt to optimize platin~
:: ,, :
20~73~
several addition agents to control electrorefining. Addition agents used Çor electroreEining include animal glue, thiourea, lignin sulfonate, alkyl sulEonate and chloride ion. Positively charged addition agents such as animal glue are drawn by 5 electrochernical Eorces to the negatively charged cathode. Positively charged addition agents are more strongly attracted to increased current density regions of peaks or nodules forrned on a cathode. The increased concentration of addition agents on peaks or nodules slows down the metal electrodeposition and levelling takes place.
Advantageously, an addition agent such as glue is preferentially a(lsorbed 10 on the peak or nodule to form a resistance layer which locally increases over-potential and levelling on the cathode surface takes place. IE excess addition agent is present, the addition agent adsorbs over an entire cathode surface which causes a loss oflevelling eEfect. If insufEicient addition agent is present, growth on peaks and nodules is not prevented and the peaks and nodules grow in an uncontrolled accelerated 15 manner. Typical optimum concentration of addition agents is in the parts per million range. Unfortunately, concentrations of addition agents are very difficult to measure in a simple and accurate manner. ~urthermore, several addition agents break downinto multiple components and eventually lose levelling effect.
Typical copper electrorefinery addition agent systerns are complicated 20 and include a combination of three or more addition agents. As a result oE high interactions between addition agents, levelling effects of new combinations of levelling agents are unpredictable. To evaluate an addition agent system time consuming laboratory or pilot plating experiments have been required. A typical experimentrequires 7 to 14 days to complete. It would require about 5 to 10 years (without25 simultaneous experiments) to investigate every combination of a system of four addition agents each at Eour different concentrations.
Several techniques have been developed to monitor addition agent concentrations in electrolyte. Langner et al, in U.S. Patent No. 4,834,842 describe a techniquc oE measuring efEectiveness of addition agents by measuring kinetics oE30 cathode polarization under predetermined conditions. Other techniques described in the literature have measured cathode polarization in an attempt to optimize platin~
:: ,, :
20~73~
conditions. These cathode polarization techniques are not capable of measuring the ability of an addition agent or a combination of addition agents to alter cathode levelling.
It is an object of this invention to provide an apparatus ancl method Eor 5 evaluating the ability oE an addition agent to improve cathode sur~ace during electrodeposition.
It is a further object of this invention to provide a quick and ef~ctive method for evaluating addition agents and their combination for cathode levelling.
It is a further object of this invention to provide a method for 10 controlling levelling power of electrolytes to prevent the formation of a rough nodulated and contaminated surface by adjusting the addition agents concentration.
SUMMARY OF T~E INVENTIO~
The invention provides an apparatus and method for determining Ievelling power of an electrolyte. An anode and cathode are immersed in the 15 electrolyte. The cathode has a plating surface for electrodeposition oE a metal Erom the electrolyte. The plating surface has a peak region and a base region separated and electrically isolated by an insulator. I~le peak region has 2 greater tendency to electrodeposit the metal per unit surface area than the base region. The anode and cathode are placed in a test cell or suspended in a commercial electrodeposition cell.
20 A means for applying current between said anode and said cathode is used Eor causing the metal from the electrolyte to electrodeposit on the plating surface oE the cathocle.
~lle current used in plating metal on the peak region and the base region are measured separately to determine levelling power of the electrolyte.
DESCRIPTION OF THE D~AWING
Figure I is a schematic diagram of an apparatus Eor measuring levelling power.
Figure 2 is a schematic side view of an optional peak electroclc having a projecting pealc rc gion.
20~973~
It is an object of this invention to provide an apparatus ancl method Eor 5 evaluating the ability oE an addition agent to improve cathode sur~ace during electrodeposition.
It is a further object of this invention to provide a quick and ef~ctive method for evaluating addition agents and their combination for cathode levelling.
It is a further object of this invention to provide a method for 10 controlling levelling power of electrolytes to prevent the formation of a rough nodulated and contaminated surface by adjusting the addition agents concentration.
SUMMARY OF T~E INVENTIO~
The invention provides an apparatus and method for determining Ievelling power of an electrolyte. An anode and cathode are immersed in the 15 electrolyte. The cathode has a plating surface for electrodeposition oE a metal Erom the electrolyte. The plating surface has a peak region and a base region separated and electrically isolated by an insulator. I~le peak region has 2 greater tendency to electrodeposit the metal per unit surface area than the base region. The anode and cathode are placed in a test cell or suspended in a commercial electrodeposition cell.
20 A means for applying current between said anode and said cathode is used Eor causing the metal from the electrolyte to electrodeposit on the plating surface oE the cathocle.
~lle current used in plating metal on the peak region and the base region are measured separately to determine levelling power of the electrolyte.
DESCRIPTION OF THE D~AWING
Figure I is a schematic diagram of an apparatus Eor measuring levelling power.
Figure 2 is a schematic side view of an optional peak electroclc having a projecting pealc rc gion.
20~973~
Figure 3 is a graph of cathode peak current versus time with various concentrations of lignosulfonate in a copper electrorefining solution.
Figure 4 is a graph of levelling power versus concentration for lignosulfonate in a copper electrorefining solution.
Figure 5 is a graph of cathode peak current versus time with various concentrations of thlourea in a copper electrore~ming solution.
Figure 6 is a graph of levelling power versus concentration of thiourea in a copper electrorefining solution.
~igure 7 is a graph of peak current versus time for two electrolytes having similar ingredients.
DESCRIPTION OF PREFE~RED ~:MBODIMENT
It has been discovered that a newly developed electrode system has the ability to measure the levelling effect o~ addition agents in electrolyte. The electrode system includes a cathode which contains a peak region (or several peak regions) and a i lat base or valley region. Current flow is measured separately for peak and base regions to quickly determine the levelling effect of various combinations of addition agents.
Referring to Figure 1, the apparatus includes galvanostat lU which generates a constant current through electrolyte 12 between anode 14 and cathode 16.
Electrolyte 12, anode 14 and cathode 16 are all contained in test cell 18. As analternative to test cell 18, any means to hold anode 14 and cathode 16 in electrolyte 12 may be used. For example, anode 14 and cathode 16 may be simply suspended by clamps, bolts or wires in a commercial electrolytic solution. Cathode 16 is of a"sandwich" structure having three peak regions 20 and three base regions 22 placed upon an insulating structure. The peak regions are placed closer to anode 14 to create a current densit~ adjacent the peak regions 20 that is stronger than the current density adjacent the base regions 22. ~Iternatively, geometry such as a projecting cathode may be used to create a greater tendency for metal to electrodeposit per unit surEace area on peak regions 20 than base regions 22. For purposes of the invention, unit surface area is defined as total plating surface. Galvanostat 10 provides sufficient current to electrodeposit metal on the peak regions 20 and base regions 22. Alternatively, other .
2~973~
Figure 4 is a graph of levelling power versus concentration for lignosulfonate in a copper electrorefining solution.
Figure 5 is a graph of cathode peak current versus time with various concentrations of thlourea in a copper electrore~ming solution.
Figure 6 is a graph of levelling power versus concentration of thiourea in a copper electrorefining solution.
~igure 7 is a graph of peak current versus time for two electrolytes having similar ingredients.
DESCRIPTION OF PREFE~RED ~:MBODIMENT
It has been discovered that a newly developed electrode system has the ability to measure the levelling effect o~ addition agents in electrolyte. The electrode system includes a cathode which contains a peak region (or several peak regions) and a i lat base or valley region. Current flow is measured separately for peak and base regions to quickly determine the levelling effect of various combinations of addition agents.
Referring to Figure 1, the apparatus includes galvanostat lU which generates a constant current through electrolyte 12 between anode 14 and cathode 16.
Electrolyte 12, anode 14 and cathode 16 are all contained in test cell 18. As analternative to test cell 18, any means to hold anode 14 and cathode 16 in electrolyte 12 may be used. For example, anode 14 and cathode 16 may be simply suspended by clamps, bolts or wires in a commercial electrolytic solution. Cathode 16 is of a"sandwich" structure having three peak regions 20 and three base regions 22 placed upon an insulating structure. The peak regions are placed closer to anode 14 to create a current densit~ adjacent the peak regions 20 that is stronger than the current density adjacent the base regions 22. ~Iternatively, geometry such as a projecting cathode may be used to create a greater tendency for metal to electrodeposit per unit surEace area on peak regions 20 than base regions 22. For purposes of the invention, unit surface area is defined as total plating surface. Galvanostat 10 provides sufficient current to electrodeposit metal on the peak regions 20 and base regions 22. Alternatively, other .
2~973~
5- PC-41~2 means for electrodepositing metal on cathode base region 22 and peak region 20 may be studied. For example, systems that periodical}y reverse current to stir electrolyte may be studied. When using tçst cell 18, electrolyte 12 is most preferably heated to within about 5C of the electrolyte to be tested. Test cel} 18 may be heated by any S means for heating a tesl cell such as a hot plate.
During electrodeposition, current flowing to the peak regions 20 and base region 22 is determined separately with voltmeters 26 and 2~ and resistors 30 and 32. Advantageously, resistors 30 and 32 have a similar resistance of about 1-5 ohms.
Wiring is used to connect the base and peak regions to current measuring devices.
10 From the rneasured voltage and resistance, current may be calculated. Alternatively, current may be directly measured with ammeters. Most advantageously, current flowing to the peak regions and total current flowing to the base and peak regions is measured. It is recognized that material electrodeposited on the peak regions and material el~ctrodeposited on the base regions may be weighed separately and 15 compared or simply visually compared to determine levelling effect. However, it is highly advantageous to simply electrically measure current flows to determine levelling effect.
The beneficial levelling effect with and without addition agents in an electrolyte is advantageously determined with the following formula:
LP = l~ - lp x 100 lP
where:
LP = Levelling Power Ip = Current flowing to the peak electrode(s) It = Total current flowing to the cathode The above described system models the rough surface of a cathode and provides for direct measurement of the blocking effect of addition agents on the peaks of a rough cathocle. The blocking effect is expressed as a levelling power. Levelling power is measured by determining ratio of current flowing to base regions and peak regions. Levelling power may be measured in 15 to 30 minutes. After lS to 30 minutes o~ plating, the electrolyte begins to change anA peak current begins to , 20~9735 stabilize. Most advantageously, total current over a time range is used to obtain more accurate results. For éxample, to study levelling power during nucleation, peak current and total current may be measured for the initial 5 minutes. A measurement of 5 minutes until stabilization of peak current may be used to study electrodeposition S following nucleation. Wllen peak current stabilizes, the test is completed. Aftcr measuring levelling power of a commercial electrolyte, addition agents may be manually adjusted or automatically adjusted to optimize levelling power.
The sandwich electrode of Figure 1 was constructed out of copper and chlorinated polyvinyl chloride (CPVC3 material using an adhesive. For long term use an adhesive that can withstand harsh environments at increased tempera~ures or adesign that does not utilize adhesive is preferred. Cathodes 16 are preferably constructed with base regions and peak regions constructed of a stable metal such as platinum. Using a platinum cathode allows for cleaning oE the anode by simply reversing polarity of galvanostat 10 to redissolve plated material into the electrolyte.
Similarly, anode 14 is preferably constructed of metal deposited on the cathode or a stable metal such as platinum or lead-antimony ailoy to prevent dissolution of the anode into electrolyte 12, depending upon the process studied. For example, a lead-antimony alloy is preferred for electrowinning of copper studies. Anode 14 preferably has a surface area of at least 10 times the surface area of the conductive surface area of the cathode to provide uniform current flow to the cathode.
Although cathodes preferably have flat base and peak regions, peak regions may have a projecting con~lguration. Referring to Figure 2~ peak region 34 oli cathode 36 has a solid conical shape. Peak tegion 34 preferably projects toward an anode to create a greater tendency to electrodeposit metal per unit surface area. Base regions 38 are isolated from peak region 34 with insulator 40. Preferably, surface area of peak region 34 is equal to surface area of base regions 38. The advantage of the structure of Figure 2 is that CPVC adhesive may be used to hold the entire cathode structure together.
An experimental set-lp was produced having a copper anode. The 3~) copper anode had a surface area of 4 cm2. The cathode used had a structure similar to the cathode of Figure 2. The cathode had 3 flat platinum base regions ancl 1 conically shaped peak region. The surface area of the base region and peak region . . ......... , . - ~
~ ~ ,,. . ;
-2~73~
During electrodeposition, current flowing to the peak regions 20 and base region 22 is determined separately with voltmeters 26 and 2~ and resistors 30 and 32. Advantageously, resistors 30 and 32 have a similar resistance of about 1-5 ohms.
Wiring is used to connect the base and peak regions to current measuring devices.
10 From the rneasured voltage and resistance, current may be calculated. Alternatively, current may be directly measured with ammeters. Most advantageously, current flowing to the peak regions and total current flowing to the base and peak regions is measured. It is recognized that material electrodeposited on the peak regions and material el~ctrodeposited on the base regions may be weighed separately and 15 compared or simply visually compared to determine levelling effect. However, it is highly advantageous to simply electrically measure current flows to determine levelling effect.
The beneficial levelling effect with and without addition agents in an electrolyte is advantageously determined with the following formula:
LP = l~ - lp x 100 lP
where:
LP = Levelling Power Ip = Current flowing to the peak electrode(s) It = Total current flowing to the cathode The above described system models the rough surface of a cathode and provides for direct measurement of the blocking effect of addition agents on the peaks of a rough cathocle. The blocking effect is expressed as a levelling power. Levelling power is measured by determining ratio of current flowing to base regions and peak regions. Levelling power may be measured in 15 to 30 minutes. After lS to 30 minutes o~ plating, the electrolyte begins to change anA peak current begins to , 20~9735 stabilize. Most advantageously, total current over a time range is used to obtain more accurate results. For éxample, to study levelling power during nucleation, peak current and total current may be measured for the initial 5 minutes. A measurement of 5 minutes until stabilization of peak current may be used to study electrodeposition S following nucleation. Wllen peak current stabilizes, the test is completed. Aftcr measuring levelling power of a commercial electrolyte, addition agents may be manually adjusted or automatically adjusted to optimize levelling power.
The sandwich electrode of Figure 1 was constructed out of copper and chlorinated polyvinyl chloride (CPVC3 material using an adhesive. For long term use an adhesive that can withstand harsh environments at increased tempera~ures or adesign that does not utilize adhesive is preferred. Cathodes 16 are preferably constructed with base regions and peak regions constructed of a stable metal such as platinum. Using a platinum cathode allows for cleaning oE the anode by simply reversing polarity of galvanostat 10 to redissolve plated material into the electrolyte.
Similarly, anode 14 is preferably constructed of metal deposited on the cathode or a stable metal such as platinum or lead-antimony ailoy to prevent dissolution of the anode into electrolyte 12, depending upon the process studied. For example, a lead-antimony alloy is preferred for electrowinning of copper studies. Anode 14 preferably has a surface area of at least 10 times the surface area of the conductive surface area of the cathode to provide uniform current flow to the cathode.
Although cathodes preferably have flat base and peak regions, peak regions may have a projecting con~lguration. Referring to Figure 2~ peak region 34 oli cathode 36 has a solid conical shape. Peak tegion 34 preferably projects toward an anode to create a greater tendency to electrodeposit metal per unit surface area. Base regions 38 are isolated from peak region 34 with insulator 40. Preferably, surface area of peak region 34 is equal to surface area of base regions 38. The advantage of the structure of Figure 2 is that CPVC adhesive may be used to hold the entire cathode structure together.
An experimental set-lp was produced having a copper anode. The 3~) copper anode had a surface area of 4 cm2. The cathode used had a structure similar to the cathode of Figure 2. The cathode had 3 flat platinum base regions ancl 1 conically shaped peak region. The surface area of the base region and peak region . . ......... , . - ~
~ ~ ,,. . ;
-2~73~
were each about 0.053 cm2. The base regions were spaced 3.5 rnm from the peak region. The above experimental setup was used for the following Examples.
EXAMPLE I
A synthetic electrolyte of the following composition was used:
S Cu - 40 g/Q
Ni - 20 g/Q
H2SO4 - lS() g/Q
Cl- - 20 mg/Q
The electrolyte temperature during measuring was 65C and the average cathode current density was 182 Alm~ which simulated a commercial copper electrorefining operation. Measurements are preferably made at temperatures and current densities that simulate commercial conditions. DiEferent amounts of TembindrM
(a lignosulonate produced by Temfibre Inc. of Temiscaming, Quebec) were added to the electrolyte and the cathode peak current time profile was recorded. Cathode peak current was calculated from the measured voltage and a predetermined constant resistance. The recorded current time profile is shown in Figure 3. The results of the experiment are summarized in Table 1 and the ef~ect of Tembind concentration on the levelling power is shown in Figure 4. The lowest levelling power (LP) of the electrolyte in the presence of 20 mg/Q Cl- is around 10 mg/Q Tembind. Above 10 mg/Q Tembind, the levelling power sharply rises with increased Tembind concentration and reaches its maximum at concentrations over 100 mg/Q.
. , ~ ; - . . ~ . ; :
- . , . ~ ~
2~73~
EXAMPLE I
A synthetic electrolyte of the following composition was used:
S Cu - 40 g/Q
Ni - 20 g/Q
H2SO4 - lS() g/Q
Cl- - 20 mg/Q
The electrolyte temperature during measuring was 65C and the average cathode current density was 182 Alm~ which simulated a commercial copper electrorefining operation. Measurements are preferably made at temperatures and current densities that simulate commercial conditions. DiEferent amounts of TembindrM
(a lignosulonate produced by Temfibre Inc. of Temiscaming, Quebec) were added to the electrolyte and the cathode peak current time profile was recorded. Cathode peak current was calculated from the measured voltage and a predetermined constant resistance. The recorded current time profile is shown in Figure 3. The results of the experiment are summarized in Table 1 and the ef~ect of Tembind concentration on the levelling power is shown in Figure 4. The lowest levelling power (LP) of the electrolyte in the presence of 20 mg/Q Cl- is around 10 mg/Q Tembind. Above 10 mg/Q Tembind, the levelling power sharply rises with increased Tembind concentration and reaches its maximum at concentrations over 100 mg/Q.
. , ~ ; - . . ~ . ; :
- . , . ~ ~
2~73~
-8- PC-~102 Effect of Tembind Concentration on Cathode Peak Cllrrent ~nd Levellin~ Power Current DeDsity = 182A/m2;
Cathode Total CulTent = 1.93 mA;
Plating t;me = 15 min.
1~ : _. -Tembind ¦ Cathode Peak Current Levelling Power (m~/Q) (mg/Q) _ .
O 1 043 ~5.0 ~ _ j 10 , 1.196_ _6l.4 1 20 _61 81.9 i- 50 0g76 _ 97.9 100 0.~53 102.5 , __- ~
A synthetic electrolyte oE the same composition and temperature as in ~xample 1 was used. Animal glue was added to the electrolyte in such a quantity that the final concentration was 1 mg/Q. Animal glue is a protein derivative ~ormed primarily from animal skins, hides, bones and tendons. DifEerent amounts of thiourea were then added to the electrolyte and the cathode peak current time pro~lle was20 recorded. The results and parameters of the experiment are summarized in Table 2.
The recorded time profles are shown in Figure 5. The effect of thiourea on levelling power is shown in Figure 6. As can be seen the levelling power in the electrolyte increases with thiourea concentration.
Cathode Total CulTent = 1.93 mA;
Plating t;me = 15 min.
1~ : _. -Tembind ¦ Cathode Peak Current Levelling Power (m~/Q) (mg/Q) _ .
O 1 043 ~5.0 ~ _ j 10 , 1.196_ _6l.4 1 20 _61 81.9 i- 50 0g76 _ 97.9 100 0.~53 102.5 , __- ~
A synthetic electrolyte oE the same composition and temperature as in ~xample 1 was used. Animal glue was added to the electrolyte in such a quantity that the final concentration was 1 mg/Q. Animal glue is a protein derivative ~ormed primarily from animal skins, hides, bones and tendons. DifEerent amounts of thiourea were then added to the electrolyte and the cathode peak current time pro~lle was20 recorded. The results and parameters of the experiment are summarized in Table 2.
The recorded time profles are shown in Figure 5. The effect of thiourea on levelling power is shown in Figure 6. As can be seen the levelling power in the electrolyte increases with thiourea concentration.
9 2~ 3 ~
E~ect of Thiourea CDncentratioll on Cathode Penk CurTel~t ~nd Levelli~ Power Current I)ensity--209 A/m~;
S ~thode Total Current a 2.22 mA;
Plating Time = 30 nnîn.;
Cl- - 20 mg/~, Glu~ ~ 1 mg/l , _ _ ~
Thiourea Cathode Peak Current Levelling Power (mglQ) _(mA) t%) 0 1.223 81.5 _ _ _ 11 1 _ 1.187 __ 87.0 2_ 1.169 _ 89.9 _ S _ 1.133__ ~S.g S0 1.062 109.0 __ _ . . .
EX~MPLE 3 In this example the levelling power of electrolytes from two independent plant plating circuits for copper electrorefining were tested. The electrolytes contained 20 mg/Q Cl~, animal glue and Tembind. Figure 7 illustrates that the electrolytes20 produced two similar cathode peak current time profiles. ThereEore, since the two profiles were similar, the levelling power o~ both plant electrolytes were experimentally verified to be substantially identical.
In summary, the apparatus and method of the invention provide several aclvantages. The method of the invention provides the ability to measure the levelling 25 power ot an electrolyte. The method Oe the invention also reduces the time oEevaluating an electrolyte system from 7 to 14 days to only IS to 30 minutes. Finally, commercial electrolytcs may be evaluated Eor levelling power to provide a basis Eor optimizing electrodeposition by adjusting electrolyte addition agents.
.~ .
, -10- 2 Q~
While in accordance with the provisions of the statute, there is illustrated and described herein specific embodiments of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims and that certain features of the invention may sometimes be used to S advantage without a corresponding use of the other features.
.
:
E~ect of Thiourea CDncentratioll on Cathode Penk CurTel~t ~nd Levelli~ Power Current I)ensity--209 A/m~;
S ~thode Total Current a 2.22 mA;
Plating Time = 30 nnîn.;
Cl- - 20 mg/~, Glu~ ~ 1 mg/l , _ _ ~
Thiourea Cathode Peak Current Levelling Power (mglQ) _(mA) t%) 0 1.223 81.5 _ _ _ 11 1 _ 1.187 __ 87.0 2_ 1.169 _ 89.9 _ S _ 1.133__ ~S.g S0 1.062 109.0 __ _ . . .
EX~MPLE 3 In this example the levelling power of electrolytes from two independent plant plating circuits for copper electrorefining were tested. The electrolytes contained 20 mg/Q Cl~, animal glue and Tembind. Figure 7 illustrates that the electrolytes20 produced two similar cathode peak current time profiles. ThereEore, since the two profiles were similar, the levelling power o~ both plant electrolytes were experimentally verified to be substantially identical.
In summary, the apparatus and method of the invention provide several aclvantages. The method of the invention provides the ability to measure the levelling 25 power ot an electrolyte. The method Oe the invention also reduces the time oEevaluating an electrolyte system from 7 to 14 days to only IS to 30 minutes. Finally, commercial electrolytcs may be evaluated Eor levelling power to provide a basis Eor optimizing electrodeposition by adjusting electrolyte addition agents.
.~ .
, -10- 2 Q~
While in accordance with the provisions of the statute, there is illustrated and described herein specific embodiments of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims and that certain features of the invention may sometimes be used to S advantage without a corresponding use of the other features.
.
:
Claims (20)
1. An apparatus for determining the levelling power of an electrolyte comprising:
(a) an anode for immersion in the electrolyte;
(b) a cathode having a plating surface for electrodeposition of a metal from the electrolyte, said plating surface of said cathode having a peak region and a base region, said peak region and said base region being separated and electrically isolated by an insulator and said peak region having a greater tendency to electrodeposit the metal per unit surface area than said base region;
(c) a means for holding said anode and said cathode in the electrolyte; and (d) a means for applying current between said anode and said cathode sufficient for causing the metal from the electrolyte to electrodeposit on said plating surface of said cathode.
(a) an anode for immersion in the electrolyte;
(b) a cathode having a plating surface for electrodeposition of a metal from the electrolyte, said plating surface of said cathode having a peak region and a base region, said peak region and said base region being separated and electrically isolated by an insulator and said peak region having a greater tendency to electrodeposit the metal per unit surface area than said base region;
(c) a means for holding said anode and said cathode in the electrolyte; and (d) a means for applying current between said anode and said cathode sufficient for causing the metal from the electrolyte to electrodeposit on said plating surface of said cathode.
2. The apparatus of claim 1 wherein said means for generating current between said anode and said cathode is a galvanostat.
3. The apparatus of claim 1 wherein said peak region and said base region are separated and electrically isolated by an insulator and wherein the apparatus includes a means for measuring current flow to said peak region and a means for measuring total current flow to said cathode.
4. The apparatus of claim 1 wherein said anode has a surface area at least 10 times total surface area of said peak region combined with said base region.
5. The apparatus of claim 1 wherein said apparatus includes a means for heating said electrolyte.
6. The apparatus of claim 1 wherein said peak region is surrounded by at least one flat base region.
7. The apparatus of claim 1 wherein area of said base region and said peak region have approximately equal surface areas.
8. An apparatus for determining the levelling power of an electrolyte comprising:
(a) an anode for immersion in the electrolyte;
(b) a cathode having a plating surface for electrodeposition of a metal from the electrolyte, said plating surface of said cathode having a peak region and a base region and said peak region being spaced closer to said anode than said base region for creating a greater tendency to electrodeposit the metal on said peak region per unit surface area than said base region;
(c) a means for holding said anode and said cathode in the electrolyte; and (d) a means for applying constant current between said anode and said cathode for causing the metal from the electrolyte to electrodeposit on said plating surface of said cathode.
(a) an anode for immersion in the electrolyte;
(b) a cathode having a plating surface for electrodeposition of a metal from the electrolyte, said plating surface of said cathode having a peak region and a base region and said peak region being spaced closer to said anode than said base region for creating a greater tendency to electrodeposit the metal on said peak region per unit surface area than said base region;
(c) a means for holding said anode and said cathode in the electrolyte; and (d) a means for applying constant current between said anode and said cathode for causing the metal from the electrolyte to electrodeposit on said plating surface of said cathode.
9. The apparatus of claim 8 wherein said peak region and said base region are separated and electrically isolated by an insulator and wherein the apparatus includes a means for measuring current flow to said peak region and a means for measuring total current flow to said cathode.
10. The apparatus of claim 8 wherein said peak region and said base region are constructed of a stable metal having a greater electrochemical stability than the metal from the electrolyte for allowing cleaning of the cathode by generating a current of reverse polarity.
11. The apparatus of claim 8 wherein said anode has a surface area at least 10 times total surface are of said peak region combined with said base region.
12. A method of determining the levelling power of an electrolyte comprising the steps of:
(a) providing an anode and a cathode within an electrolyte, said cathode having a peak region and a base region within said peak region having a greater tendency to electrodeposit a metal per unit surface area than said base region;
(b) applying a current between said anode and said cathode to electrodeposit the metal from said electrolyte on said cathode; and (c) measuring proportion of current that travels to said peak region and said base region.
(a) providing an anode and a cathode within an electrolyte, said cathode having a peak region and a base region within said peak region having a greater tendency to electrodeposit a metal per unit surface area than said base region;
(b) applying a current between said anode and said cathode to electrodeposit the metal from said electrolyte on said cathode; and (c) measuring proportion of current that travels to said peak region and said base region.
13. The method of claim 12 including the additional step of:
adjusting addition agent content in said electrolyte in response to the proportion of current at said peak region and said base region.
adjusting addition agent content in said electrolyte in response to the proportion of current at said peak region and said base region.
14. The method of claim 12 including the additional step of:
reversing current to said cathode to redissolve metal into the electrolyte.
reversing current to said cathode to redissolve metal into the electrolyte.
15. The method of claim 12 wherein said electrolyte is maintained at a temperature within about 5°C of a temperature a system to be tested operates.
16. The method of claim 12 wherein said peak region and said base region are separated and electrically insulated by an insulator and wherein proportion of current travelling to said peak region and said base region is measured with said peak region and said base region of said cathode having equal surface areas.
17. The method of claim 12 wherein said current is applied with a galvanostat.
18. The method of claim 12 wherein said peak regions of said cathode project toward said anode.
19. The method of claim 12 wherein the levelling power is determined by a ratio between current at said peak region and current at said base region.
20. The method of claim 19 wherein said current is measured over a predetermined time interval.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2059735 CA2059735A1 (en) | 1992-01-21 | 1992-01-21 | Electrode and method for measuring levelling power |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2059735 CA2059735A1 (en) | 1992-01-21 | 1992-01-21 | Electrode and method for measuring levelling power |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2059735A1 true CA2059735A1 (en) | 1993-07-22 |
Family
ID=4149123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2059735 Abandoned CA2059735A1 (en) | 1992-01-21 | 1992-01-21 | Electrode and method for measuring levelling power |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2059735A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2950089A1 (en) * | 2014-05-26 | 2015-12-02 | GS Yuasa International Ltd. | Galvanic cell type sensor |
-
1992
- 1992-01-21 CA CA 2059735 patent/CA2059735A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2950089A1 (en) * | 2014-05-26 | 2015-12-02 | GS Yuasa International Ltd. | Galvanic cell type sensor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ghaemi et al. | Effects of direct and pulse current on electrodeposition of manganese dioxide | |
| US5236571A (en) | Electrode and method for measuring levelling power | |
| US5273641A (en) | Electrode and method for measuring levelling power | |
| CA2059735A1 (en) | Electrode and method for measuring levelling power | |
| US5124011A (en) | Cyclic voltammetry | |
| US5202018A (en) | Process for electrochemical dissolution of semiconductors | |
| CA1179751A (en) | Controlling metal electro-deposition using electrolyte containing, two polarizing agents | |
| US3121053A (en) | Analytical electroplating apparatus | |
| Velayutham et al. | Preparation of a polypyrrole—lead dioxide composite electrode for electroanalytical applications | |
| JPH07840B2 (en) | Method for controlling electroplating additive and apparatus therefor | |
| Pawar et al. | Mechanism of electrodeposition of Bi-Sr-Ca-Cu alloyed films | |
| SU145102A1 (en) | The method of electrodeposition of indium-nickel alloys | |
| Abd El Rehim | The effect of superimposed ac on dc on the electrodeposition of Cu-Zn alloys | |
| MASAKI et al. | Bright silver plating from cyanide-free bath | |
| Šestan et al. | The influence of current density and electrodeposition time on the quality of nickel coating | |
| JPH06100570B2 (en) | Life prediction method for coated metal | |
| Gupta | Galvanotactic reaction of infective larvae of Trichostrongylus retortaeformis | |
| IMANAGA et al. | Concentration Profiles on the Cathode Surface in the Electrodeposition of Nikel-Cobalt Alloy | |
| Ellis et al. | Electrochemical Processes Using Independently Controlled Voltages in Alternation | |
| Juzeliūnas et al. | Some kinetic peculiarities of discharge ionization of cadmium on surfaces with various morphological properties | |
| KAMEGAYA et al. | A Newly Designed Titanium Anode for Oxygen Evolution at High Current Densities | |
| Radhakrishnamurthy et al. | A novel method of current efficiency determination | |
| Roev et al. | Application of a Built‐In Microscopic Antimony Electrode for Potentiometric Studies on Zinc‐Nickel Co‐Deposition | |
| DE1817068A1 (en) | Device for measuring the effective surface of intricately shaped, electrically conductive objects | |
| Muramaki et al. | Anodic oxidation of aluminium in sulphuric acid under potentiostatic conditions |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |