JPS5842786A - Electrodeposition of tin-lead alloy - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved plating bath for depositing tin-lead alloys onto various substrates. In particular, the present invention uses salt-compatible acids, namely fluoroboric acid, as well as bath-soluble tin and lead salts such as tin fluoroborate I) and lead fluoroborate (1), together with special additives. This invention relates to the precipitation of a bright metallic tin-lead alloy from a modified bath used as a component.

There are many prior patents related to tin-lead alloy plating baths and plating methods. Among these, those closely related to the present invention are U.S. Patent Nos. 3,730,853 and 3.749,64.
No. 9; No. 3,769,182; No. 3,785,9
No. 39; No. 3.850, No. 765; No. 3,875
, No. 029; No. 3,905,878; No. 3,92
No. 6,749; No. 3,954,573; No. 3,9
No. 56,123; No. 3,977.949; No. 4,
No. 000,047; No. 4,135,991; No. 4
, 118,289; and British Patent No. 1,351,87.
No. 5 and No. 1,408,148.

Despite the large number of literature and the proposed bath compositions, only one tin-lead alloy with a bright metallic appearance has been found! There is still room for improvement in baths for efficient deposition on various fabrics. Other important properties are high-speed plating and leveling properties. Many of the tin--lead alloy bath compositions that have been proposed so far are
All of the ingredients used in the preparation of the baths indicate that consideration must be given not only to the plating gloss but also to other properties such as those mentioned above.

One of the objects of the present invention is to provide a lubricating bath that deposits a bright tin-lead alloy on various fabrics.

Another object of the present invention is to provide an electroplating bath which produces single-lead alloy plating with improved gloss even at relatively high speeds.

Still another object of the present invention is to provide a plating bath capable of producing a lead alloy plating having improved leveling properties.

Further objects of the invention will become apparent from the following description and examples.

In accordance with this invention, it has been discovered that an improved plating bath can be obtained by using a combination of soluble tin and lead salts and their compatible acids with special additives. The plating bath according to the present invention can deposit a shiny metallic tin-lead alloy on various types of fabrics at high speed.

The required combination of additives to the bath includes an aromatic amine brightener, an aromatic aldehyde brightener, a fatty aldehyde brightener, and a nonionic surfactant-based particle refiner.

According to another proposal of the invention, it is possible to effectively eutectoid copper or rhodium metal together with tin and lead in the form of a ternary alloy from this plating bath.

The plating baths of this invention are prepared using divalent tin and lead compounds preferably having the same anionic association and particularly preferably in bath soluble form such as tin heptoborate and lead fluoroborate. do. When using heptoboric acid and lead fluoroborate, a compatible acid, particularly preferably fluoroboric acid, is allowed to coexist with them in a sufficient amount to impart conductivity, and to improve the solubility of the metal salts. be maintained. The amount of soot and lead in the bath is at least sufficient to effectively precipitate the desired single-lead alloy or less than its maximum solubility in the bath.

Other bath-soluble divalent tin salts such as chloride, sulfinate, phenolsulfonate and others as well as
Lead salts may also be used in preparing the baths of this invention. Although it is possible to use tin salts and lead salts having different types of anions, it is preferable to use salts having the same type of anion. Additionally, other compatible acids such as hydrochloric acid, sulfamino acid, phenolsulfonic acid, and others may be used in place of or in conjunction with the fluoroboric acid. The acids used can have different anions than those of the tin and lead salts, but preferably the same anion. However, in the most preferred embodiment, tin and lead fluoroborates are used with fluoroboric acid.

The brightener composition of this invention is a combination of an aromatic compound, an aromatic aldehyde, and an aliphatic aldehyde. The content of each of these brighteners is at least sufficient to poison the tin-lead alloy plating, or is below their respective maximum solubility in the bath. The weight ratio of aromatic aons to aromatic aldehydes in the brightener composition is t! It is within the range of 1.25:1 to 100:1, particularly preferably within the range of about 5:1 to 20:1.

Aromatic amines or allyl amines useful in achieving the aims of this invention include ho-toluidine, p-toluidine,
Included are m-toluidine, aniline and 0-chloroaniline. The use of fluoro-chloroaniline is particularly preferred for most purposes. For example, in aromatic aldehydes,
J Rudehyde, 2-hydroxy-1-naphthaldehyde, 2
-methoxy-1-naphthaldehyde and others.

Among these, the preferred aromatic aldehyde is 1-naphthaldehyde. Preferred aliphatic aldehydes have 1 to 4 carbon atoms and include, for example, formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, crotonaldehyde, and others. The preferred aldehyde in Jin's invention is formaldehyde,
Conveniently, formalin containing 37% by weight formaldehyde is used.

The addition of nonionic surfactants as particulate additives is also often necessary. This content is sufficient to impart complete density to the tin-lead alloy plating particles, or is below the maximum solubility in the bath.

Preferably the nonionic surfactant is a commercially available one,
For example, nonylphenoxy polyethylene oxide
15, trade name); ethoxyalkylolamide (,
Am1lox L5 and 03. Trade name); Alkyl polyglycol ether ethylene oxy) (N5utr
onyx675 (trade name) and others. The most effective nonionic surfactant lamp in this invention is polyoxyalkylene ether whose alkylene group has 2 to 2 carbon atoms.

10 to 2 of ethylene oxide per mole of lipophilic group
Preferred are polyoxyethylene ethers having 0 moles, including Prizi 35-8P (trade name, Br1j
Surfactants such as polyoxyethylene lauryl ether, commercially available as 35-BP), are included.

Antioxidants may also be added to the bath to prevent the primary tin base used to replenish the bath from oxidizing to secondary tin compounds and forming precipitates. It is effective in the acidic 1)H of the plating bath, and it is effective in carrying out the method of the invention of Gakko.
Any antioxidant can be used as long as it does not adversely affect the resulting plating. The amount of antioxidant used is usually about 0.5 to 50 f/As, preferably about 5
or 10 f/l.

Particularly preferred antioxidants include aromatic sulfonic acids.

A typical aromatic sulfonic acid is 0-cresol sulfone! Includes 1% II-cresol sulfonic acid and phenolsulfonic acid.

Other sulfonic acids of phenol and cresol, such as: 2,6-dimethylphenolsulfonic acid 2-chloro-6
-Methylphenolsulfonic acid, 2.4-dimethylphenolsulfonic acid, 2.4.6-dolimethylphenolsulfonic acid, p-cresolsulfonic acid, and the like can also be used. Sulfonic acid derivatives of α- and β-7tolls can also be used.

Preferred components Yrm of the aqueous plating bath of this invention are summarized as follows.

() (2) Lead 3-20 2-8 (3) Acid
100-250 160-190 (4) Aromatic aldehyde 0.01-0.5 0.03-0.1 (5)
Aromatic amine 0.3-15 0.1-1.5 (
6) Fatty acid aldehyde 0.5-20 0.9-1
0.0(7) Nonionic surfactant 0.1-20
0.5 to 2.5.The pH of the bath at these concentrations is usually less than about 1, generally about 1 and about 0.05, although it is possible to use pH values above 1. The bath temperature and current density are each about 1
0℃ nai[, 40℃ and about 0.5A/DF? / (5A
SF) Ikil, 53 A/'DIP? (500
ASF), preferably 15°C, 25°C and 2.6 A/D, ? (25181F) yz ishiz
l A/%/(200A31F) ”T: 1h le.

The plating bath and method according to the present invention allows for a wide range of variations in the tin-lead alloy composition. Approximately (99 weight tons and 1 weight mooring)
An alloy coating of from about 99% by weight lead to 11iIIIs can be obtained. Of course, if it is desired to produce an alloy skin 81 of a different composition, the relative amounts of the bath components may be varied to impart optimum gloss, ductility, and other properties to the alloy of the desired composition. should be. From a practical standpoint, tin-lead alloy coatings having a composition of about (95 wt.- and 5 wt. lead) and solder coatings having a composition of about (60 wt.-soot and 40 wt.-lead) are particularly useful. Both can be easily produced using the bath and method according to the present invention.

Stirring, often rapid stirring, is preferred in most plating operations. Additionally, the anode:cand ratio ranges from about 1=1 to lo:1, preferably about 4:1. The baths and methods of this invention are applicable to copper, copper alloys, steel, nickel, nickel alloys, and others.

By using the bath of the present invention in the manner described above, copper and rhodium metals can be eutectoided into a soot-lead alloy without the addition of additional additives or complexing agents. Metals such as nickel, iron and indium did not eutectoid under the same conditions.

It is generally preferred that copper or rhodium be added to the bath as a bath-soluble compound having the same anionic association as lead and lead. The amount to be added is sufficient to eutectoid about 5 weight - 0 copper or rhodium in the tin-lead alloy. The bath concentrations of copper and rhodium to obtain such eutectoid coatings are approximately 0.2 to 4 t/l and 0.2 to 2 t/l, respectively.

According to another proposal of the invention, in addition to the aliphatic aldehyde or up to 50 weight ts of the aliphatic aldehyde can be replaced by the corresponding aliphatic 11',
At this time, the solder usage level: - No adverse effect on gloss or other film properties. For example, even if less than 50% by weight of formaldehyde is replaced by formic acid, the basic performance of the lead bath of this invention is maintained. For comparison, baths containing less than 50 parts by weight of formaldehyde as described above result in poor appearance of the film, regardless of the amount of formic acid added. On the other hand, the amount of formic acid added does not have to correspond exactly to the amount of formaldehyde removed, and it can also be added without formaldehyde removal. Furthermore, formic acid has little or no adverse effect on the baths of this invention even without the addition of any formaldehyde.

The advantage of replacing well over 50% by weight of formaldehyde with formic acid is that the amount of formaldehyde consumed during the plating operation is reduced, so that a relatively small amount of formaldehyde needs to be replenished.

Under certain operating conditions it may be advantageous to add boric acid to the bath to prevent or reduce the formation of free hydrofluoric acid. The amount of boric acid added is rarely sufficient to substantially reduce the formation of free hydrofluoric acid.

Typically 601/l, preferably 30 fμ. The tin-lead plating bath according to the present invention contains a surfactant and may cause foaming when used in applications where this surfactant is applied. To solve the foaming problem, use a suitable antifoaming agent of about o, oe.
This can be solved by containing the compound within the range of solubility in the bath from ct7t. A particularly preferred antifoaming agent is octyl alcohol, which is chemically and electrochemically incompatible with other bath components, but which does not cause any adverse effects on the tin-lead coating. not give.

This invention will become easier to understand after reading the following examples.

Example 1 A plating bath was prepared from the following chain components.

Ingredients
Quantum (added as borofluoride first soot) 30f/j
Lead (added as lead fluoroborate) 4 t
/l fluoroboric acid 172 t
/LO-Chloraniline 0.5 f
/l formalin 20 tons polyoxyethylene lauryl ether 2.5t/1
1-Naph aldehyde 0.05f/A water (lance) The bath prepared is stable and at 20°C, 60mm, 8F (6
The specimen was plated on a copper test piece under such conditions. The resulting tin-lead film consists of 95% lead by weight,
It had a remarkable shine.

Example 2 In the formulation of Example 1, 0.5 f/l of copper fluoroborate was added in total. When plating was carried out at 6 μm/back using this bath, it contained approximately 1% by weight of copper, 89% by weight of tin, and 5% by weight of copper.
A bright one-lead-one-steel alloy plating consisting of -90% of lead by weight was obtained.

When iron and indium metals were used in place of copper in the above divalent tin-lead bath, no eutectoiding of these metals occurred.

Example 3 A bath was prepared using the following ingredients.

Ingredients Quantum (added as the first soot of boric acid heptad) 30f/lead (added as lead boric acid heptad) 4 t/
l Fufluoroboric acid 172 f/
l Boric acid 20 f/l formalin 2 o O-chloroaniline 0.5 t/l-naphaldehyde o, osr7z polyoxyethylene lacryl ether 2.5 f/ formic acid (8
8% by weight) 2. Bath at room temperature, 6mm/D
n/, operated with a single lead anode under rapid stirring. The formaldehyde concentration was exactly the same as in Example 1, but by adding formic acid, it was made easier without the need for a subsequent formaldehyde supply tube. The resulting tin-lead plating was extremely shiny and contained 95ff1% tin and 5% by weight on board.

Example 4 A tin-lead plating bath was prepared using the following chain components: 0 Ingredients Quantity Tin (added as 1st part of boric acid heptad) 3 ot/lead (added as lead fluoroborate) 4 t/l fluoroboric acid 172 f/l boric acid 20 f/l formalin 10-40-4 aniline 0.5 about 1-7J aldehyde 0.05 f/l polyoxyethylene lauryl ether 2.5 f/l Acid (88% by weight
) 5 cr7z This bath was used in Example 3.
Operate under the conditions described in this book. Despite substituting the originally required amount of formaldehyde with 50 wt St-formic acid, it plated with exactly the same gloss as obtained with the bath of Example 1 containing 20 C1y'l of formalin and no formic acid.

Example 5 o, 06, respectively, in the plating bath according to example 1
ct7 and 0,18%/A octyl alcohol gold added to the wells.

When these baths were operated in the same manner as in Example 1, soot 1
An extremely bright lead film containing 95% by weight and 5% by weight of lead is formed on the skin.

Samples were taken from each of these baths and from the bath of Example 1, placed in bottles, capped and shaken. 0.
The foam height of the sample containing 0.6 cty/l of octyl alcohol was about 209 g - 30 ml lower than the height in the bottle containing the sample taken from the bath of Example 1. 0, 18
The foam height in the sample bottle containing cc/L octyl alcohol was almost the same as the height in the bottle containing the sample taken from the bath of Example 1. The foam disappearance time in the former was about 30 inches less than that in the latter.

Example 6 The next flavor ingredient? A plating bath was prepared using

Ingredients
Amount of tin (added as fluoroboric acid No. 1) 30f/lead (added as lead fluoroborate) s y
/l fluoroboric acid 172
t/lO-chloroaniline 0.56
f/L formalin 20C
11t polyoxyethylene lauryl ether 2.
5f/11-7J aldehyde 0.11
The f/j water balance preparation bath was stable and the copper specimens were plated at 9120° C. and 6 μm Av with stirring. The resulting tin-lead film was extremely shiny and contained 60 parts by weight of soot and 40 parts by weight of lead. Prepare a plating bath of type 511 and peel.

A - Bath of Example 1 B - Bath of Example 1 without nonionic surfactant - Bath of Example 1 without aliphatic aldehyde - Bath of Example 1 without aromatic amine E - Aromatic Baths of Example 1 without Group Aldehydes These baths were operated under the same conditions as in Example 1 and the following results were obtained.

Bath Glossy, smooth film Bath B Black sponge film containing dendritic particles Bath 0 Cloudy metallic white film Bath D Cloudy gray or black cloudy bath K Semi-gloss film with skip plating in high current density areas, low current density Partly white cloudy film Example 8 Ratio of aromatic amine to aromatic aldehyde is 1.25:
1 to 100: To illustrate the effect tube when using a bath outside the range of 1, an electroplating bath was prepared using the following components.

Ingredients Quantum (added as the first soot of boric acid heptadide) 30f/lead (added as lead fluoroborate) 4t/
l Fluoroboric acid 172 t
/l formalin 20 ct
,/l polyoxyethylene lauryl ether 2:
5f/lO-Chloraniline variation 1
-Naphthaldehyde Variation In these experiments, tin-lead alloy plating 1 was applied on brass fabric under conditions of bath temperature 20°C and 6vDn11 vigorous stirring. 0-
The ratio of chloraniline to l-phthaldehyde was changed as follows: 0 - Normal - Brightness within the brightener ratio range High - Upper limit of the ratio range - Concentration at a distance - Wu ratio Concentrations below the lower limit of the range This method gave the following results.

0-Chloraniline 1-Natutaldehyde
High Normal Skip plating in low current density areas High High Cloudy skip plating Normal Normal Bright smooth coating The above embodiments are for illustrative purposes only and do not fall within the scope of this invention. It is obvious that various changes and modifications have been made without exception.

1 other person

Claims (11)

[Claims] (1) a tin-lead electroplating bath in which divalent tin is soluble in the bath in an amount at least sufficient to effectively deposit the desired tin-lead alloy on the substrate up to its maximum solubility in the bath; salts and divalent ship salts; an acid compatible with the mosquito salts in an amount at least sufficient to impart conductivity to the bath and maintain the solubility of the salts in the bath; an effective amount of a nonionic surfactant as a particle refiner; both are present in sufficient amounts and the ratio of aromatic amine to aromatic aldehyde is about 1.25:1.
A tin-lead electroplating bath comprising a brightener composition within the range of 1 to 100:1. (2) The electroplating bath according to claim 1, wherein the tin salt and the lead salt are fluoroboric acid tin salt and lead fluoroborate, respectively. (3) The electroplating bath according to claim 1, wherein the compatible acid is fluoroboric acid. 4. Electroplating bath according to claim 1, characterized in that it also contains an alloying metal selected from the group consisting of copper and rhodium metals. (5) The electroplating bath according to claim 1, characterized in that boric acid is present in the bath. (6) The electroplating bath according to claim 1, characterized in that one type of antifoaming agent is contained in the bath in t%. (7) The electroplating bath according to claim 6, wherein the antifoaming agent is octyl alcohol. (8) Electroplating bath according to claim 1, characterized in that up to 50% by weight of the aliphatic aldehyde is replaced by the corresponding aliphatic acid. (9) Ingredients in the following amounts, namely: 5 to 50 flt lead
3-20 fμ compatible acid 1
00~250 f/Nonionic surfactant 0.1~
20 t/ is aromatic amine θ, 3-1 st/ is aromatic aldehyde 0.01-0.5? 2. The electroplating bath according to claim 1, wherein / is an aliphatic aldehyde of 0.5 to 20 t/l. (10) Tin and lead are added as tin heptafluoroborate and lead heptoborate, the compatible acid is fluoroboric acid, and the nonionic surfactant is polyoxyethylene lauryl ether. , the aromatic amine is 0-chloroaniline, the aromatic aldehyde is 1-natal aldehyde, and the aliphatic aldehyde is formalin. . (11) The electroplating bath according to claim 10, characterized in that up to 50 weight qII of formaldehyde is substituted with formic acid. (12. Claims 1, 2, 3, and 4)
Term, 5th term, 6th term, 7th term, W, 8th term, 9th term, 1st term
Light-colored tin-lead formed by passing current between the anode and cathode through the electroplating bath of Item 0 or @ Item 11 and plating for a sufficient period of time to form the desired tin-lead alloy film. Method of electrodeposition of alloys.