JPS5996257A - Composition for electroless silver plating by friction and plating method - Google Patents

Abstract

PURPOSE:To provide a titled non-aq. soln. type compsn. which does not require any plating bath tank and permits electroless and thick plating by incorporating silver salt, hydrogenated boron compd. and the salt of the metal selected from Li, Ba, Ca, Mg, Al, etc. CONSTITUTION:A titled compsn. for electroless silver plating by friction contains (a) silver salt (e.g.; silver acetate, silver sulfate, silver nitrate) (b), hydrogenated boron compd. (e.g.; NaBH4), (c) salt of the metal selected from Li, Ba, Ca, Mg, Al and Cu and is a non-aq. soln. type compsn. Any ionizable compound, such as sulfate, nitrate, halide or the like is usable for the above-described component (c). The general blending ratio of each component is 5-100pts.wt. the component (b) and 10-200pts.wt. the component (c) basing on 100pts.wt. the component (a). The plating by using such compsn. is accomplished effectively by placing a suitable amt. of the powder compsn. on an object to be plated consisting of a metal and rubbing the same from the top thereof with a fibrous material contg. a small amt. of water.

Description

[Detailed Description of the Invention] (Subject of the Invention) The present invention applies frictional and electroless plating (prior art). Plating of large items and plating of installed items on-site. When using a plating bath, if you use a plating bath or electroless plating method, you will have to use a large plating bath or Tahiro plating solution, and you will have to remove the installed object to be plated. Therefore, it is very inconvenient in terms of cropping efficiency, work efficiency, and economy.

For this reason, only a few plating compositions are commercially available that do not require a full plating bath and can be plated without using iS. This composition contains a small amount of water. : By attaching it to the surface of the article to be plated and rubbing it with a cloth or sponge, it is possible to completely deposit the metal. However, the drawback of this plating composition is that thick plating cannot be achieved, and even if the plating operation is continued, the thickness is limited to about 1 μm at most.

(Summary of the Invention) An object of the present invention is to provide a friction-based silver plating composition that does not require a full plating bath, can be applied electrolessly and thickly, and a method for plating using the composition. be.

The plating composition of the present invention comprises the following components (a) to (C):
(a) Silver salt, (b) Li, Ba, Ca, Mg, At, λ4n.

It is characterized by containing salts of metals selected from Zn, Co, Ni, Sn and Cu, and being non-aqueous solution type.

Each component constituting the composition of the present invention will be explained.

Examples of silver salts used as a silver supply source, which is component (a), include silver acetate, silver nitrate, silver chloride, silver sulfate, and silver saponide. Particularly preferred are silver acetate, silver sulfate and silver nitrate.

It is presumed that the borohydride compound, which is the component (b), releases all lime scale and is used as a reducing agent. Sodium borohydride, potassium borohydride, lithium borohydride, triethyllithium borohydride, Dimethylamine borane ((CH3)2HNBHsl, etc.) may be used. Particularly useful is sodium borohydride.

(C) Components Lit 13a, Ca, Mg, kt.

Salts of Mn, Zn,
Any material that can be ionized, such as aged music, can be used. Specifically, for example, Li5o.

LiCt, LiNO2, LIBr, Li2C
O5t Ma.

BaSO4, BaCO3, BaCt2, caso,,
Ca(NO3)2゜Mg C1,2,Mg SO4,A
tC4, A72 (804)3, Mn3O4.

MnCt2. ZnSO4, ZnCl2. C080,,C
0Ct2゜N15o, , (CH3C00)2 Ni
, 5nso4.5nct2゜CuSO4,(CH3C
OO)2Cu, CLIO, cu, o, etc. The inventors conducted experiments on all of these, and found that, in particular,
Lithium and magnesium metal salts are excellent in terms of the smoothness and gloss of the plating film, especially L%S.
04, L' NO3, L I C1゜MgSO
4. DJgCt was confirmed to be excellent.

In the present invention, all of the above-mentioned components (a) to (C) are II! ri or two or more types can be used.

In addition to the above-mentioned components, the present invention also uses known slowing agents such as sodium bicarbonate used in cup electrolytic plating, gloss improvers such as saccharin sodium, stearic acid and lower alcohols to improve the elongation of the plated film, etc. can also be added.

Regarding the general blending ratio of each ingredient, silver salt 100
Based on parts by weight, 5 to 100 parts by weight of reducing agent, 10 to 200 parts by weight of salts of metals having a less standard electrode potential than silver, 0 to 300 parts by weight of buffering agent, and 0 to 50 parts by weight of gloss improver. The appropriate amount of the elongation improver is in the range of 0 to 30 parts by weight.

It is desirable to store the plating composition of the present invention in a manner that excludes moisture, or to store it separately in sodium borohydride or silver fence.

Among the plating methods using a composition (non-explosion), the most effective method is to apply the plating composition consisting of a powder mixture on an object to be plated consisting of all metals, - A method of rubbing with a fibrous material containing a small amount of water, such as a fibrous material such as cotton cloth or polyester fiber cloth, or a sponge, and a method of placing the plating composition on the object to be plated and adding a small amount of water to it. In this method, the material is soaked in water to make it wet, and then rubbed with a fiber material, sponge, etc.

Another method is to add a small amount of water to the plating composition in advance to form a wet layer or slurry state, place this on the object to be plated, and then rip it with a fully fibrous material, sponge, etc.
! There is also a way to distance f”j.

It is most effective to carry out plating by adding a small amount of the plating composition onto the broken plated body until the desired plating film thickness is achieved. Of course, it is done from outside with hydration provided.

The plating composition of the present invention is particularly useful for plating the surfaces of copper-based or iron-based articles.

Example 1 (On a H-purified copper plate, +t' of the missing parts (2i) to (f)
Place a plating composition (powdered rice mixture) consisting of
Using a cloth moistened with water and gold, apply 20 to 50 yen/
A silver plating film was deposited by polishing at a speed of seconds. In this case, the relationship between the fecal amount (in terms of silver amount) and the plating film thickness of the above composition for 1 cr/12 equivalents of copper plate is shown in the figure:
aE Shown by line A. Curve B shows the results without the addition of lithium sulfate. The deposited film was smooth and glossy.

〔composition〕

(a) Silver acetate (C)I, COOAg), 1
00 parts by weight (b) Sodium borohydride (NaB
H,) 25 parts by weight (C) Sodium saccharin (CaH+C08O2
NNa) 25 parts f) 1 part (d) Lithium sulfate (Li2SO4) 50
Vehicle weight section (e) Steering wheel t9 (CH3 (CH2)
16 C00H) 25 parts by weight (f) Sodium carbonate (Na14cOa)
225 fii amount: 7 parts Example 2 In the composition of Example 1, instead of lithium sulfate as component (d), 50 heavy metal salts of Z
plating was carried out using 20 different compositions of gold.

The plating operation was continuously carried out while supplying the composition #ifi until the desired film thickness was achieved. As a result, silver 8 JM with a thickness of 10 μm was easily formed. Of the 20 serious problems mentioned above, LiN0. , t;- and RJ'gSO, are the Li
Along with 5O, the film had excellent smoothness and gloss.

(Effects of the Invention) In the present invention, the metal salt yA, which is the component (C), precipitates through the action of the metal salt yA, which is the component (C). It is assumed that the precipitation progresses without reaching the Showa era. This made thick plating possible. Of course, equipment such as a plating bath is not required, and is very necessary for on-site plating and plating of large items.

[Brief explanation of the drawing]

The figure shows the relationship between the plating film thickness when all plating is performed using a silver plating composition according to an embodiment of the present invention and the amount of the composition required (value converted to silver amount). This is a graph showing.

Claims (1)

[Claims] 1. The following components (a) to (C): (a) silver salt, (b) hydrogenated borosilicate compound, (c) Li, Ba, Ca, Mg, A-1 , Mn. 1. A composition for electroless silver plating by friction, which contains all gold-based salts selected from Zn, Co, Ni, Sn and Cu, and is of a non-aqueous solution type. 2. The following components (a) to (C): (a) Silver salt; (b) Boron hydride compound 1; (C) Li, Ba, Ca, Mg, A4. Mn. A composition in the form of a non-aqueous solution containing metal salts selected from Zn, Co, Nt, Sn and Cu is applied onto the object to be plated, and the composition is mixed with the composition in a wet IM state.