JPS62199796A - Parts for electronic and electrical appliances - Google Patents

Abstract

PURPOSE:To obtain parts for electronic and electrical appliances having superior heat resistance by forming an underlayer of a noble metal on a metallic plate by plating and a layer of other noble metal on the underlayer by plating. CONSTITUTION:A metallic plate of Fe, an Fe alloy, Cu, a Cu alloy, metallized ceramics or the like is prepd. An Au or Ag underlayer of >=0.1mum thickness is formed on the metallic plate by plating or an Au or Ag layer is formed by striking. A layer of a noble metal is further formed by plating. In case where the Au underlayer or the Au layer is formed on the metallic plate, an Ag or Ag alloy layer is formed. In case where the Ag underlayer or the Ag layer is formed, an Au or Au alloy layer is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective) The present invention relates to parts for electronic and electrical equipment, such as a lead fly 11 or a terminal connector, in which a metal plate is plated with a noble metal such as Au or Ag.

(Prior art) Precious metals such as Au and Ag have excellent chemical and physical properties and are widely used in various electronic and electrical parts, but they are very expensive, so it is important to make the plating layer as thin as possible. is desired. On the other hand, true metal plating materials used as electronic and electrical components may be exposed to heat of several hundred degrees, and solderability may deteriorate due to oxidation of the underlying metal or diffusion of the underlying metal into the precious metal surface layer in such high-temperature environments. However, there were disadvantages in that the bonding properties and the like were significantly deteriorated and the color changed.

Therefore, in order to prevent the deterioration of quality under the above-mentioned high-temperature environment, 5n-Ni and 5n-Go are used as the base plating before noble metal plating.

Attempts have been made to apply Pb-Ni, Ni, etc.
Even with these base platings, if kept in the atmosphere at 450°C for 3 minutes, the noble metal plating layer will change to, for example, Au0.
．． A material that exhibits sufficient solderability and bonding properties cannot be obtained with a plating thickness as thin as 1μ or A g 0.5μ, and in order to satisfy the above characteristics, the precious metal plating layer must be plated as thick as several μ. The disadvantage was that it had to be done. As described above, conventional underplating products consume large amounts of precious metals, resulting in significant economic losses.

(Structure) The present invention was achieved as a result of intensive research in view of the current situation, and the precious metal plating layer was kept in the atmosphere at 450°C for 3 minutes at a thin plating thickness of about 001 μm of Au or 0.5 μm of Ag. The object of the present invention is to provide a precious metal plating material that exhibits sufficient solderability and bonding properties even after soldering. That is, the present invention provides a gold or silver base plating layer on a metal plate, and a silver or silver alloy plating on the base plating layer when the base plating layer is gold plating, and gold or gold when the base plating layer is silver plating. The present invention relates to parts for electronic and electrical equipment having an alloy plating layer, and parts for electronic and electrical equipment in which the base plating layer is a gold or silver strike plating layer.

In addition, the gold plating layer or silver plating layer as the base is 0.
If the thickness is 0.01 μm or more, the effect of improving so-called heat resistance, which maintains good solderability and bonding properties even after heating, is sufficient. Therefore, 0.01 like this
In order to apply a thin plating layer of about .mu. to 0.1 .mu.m, it is preferable to use a strike plating bath because a dense and uniform film can be obtained. The main silver strike plating solution can be used for copper, copper alloys, iron alloys, etc., and strike plating is usually performed using a particularly low concentration silver plating solution. This is because silver cementation occurs instantaneously when immersed in a highly concentrated silver plating bath, and even if gold plating is applied on top of that, a film with good adhesion cannot be obtained. Further, the underlying gold strike liquid can be similarly used for copper, copper alloys, iron alloys, etc. Strike plating is then typically performed using a gold plating solution with a low concentration. By using the strike plating solution as described above, a highly uniform, dense, and highly adhesive film is formed, and then a predetermined upper layer plating is performed. Equipment parts can be obtained.

Although the mechanism by which such gold or silver plated materials deteriorate in high-temperature environments has not necessarily been theoretically elucidated, it is generally thought to be as follows. In other words, in the case of gold-plated materials, Cu, Fe,
Ni, Co, etc. diffuse onto the gold-plated surface and come into contact with the atmosphere, forming oxides and causing deterioration of solderability or bonding properties. In addition, in the case of silver-plated materials, oxygen easily permeates under high-temperature environments, so oxygen combines with the base metal or the conventional base plating, which similarly leads to the formation of an oxide film and reduces solderability. Alternatively, it may cause deterioration of bonding properties.

Therefore, in the present invention, by applying silver plating, which is a dissimilar metal, as the base plating for gold or gold alloy plating material, the formation of the above-mentioned oxides in front of the gold plating is prevented,
Furthermore, gold plating is applied as a base plating for silver or silver alloy plated materials to prevent oxidation of the base.

As the base metal, Fe, Fe alloy, Cu, Cu alloy, ceramic metallized material, etc. can be used.

Note that in the present invention, it is of course possible to further apply another base plating before the base plating of the present invention, and the present invention naturally includes these.

Next, the present invention will be explained based on examples.

(Example) Stainless steel (SUS430.Cl 11+m+t) and phosphor bronze (0.20 nmt) were degreased and pickled using a known method, and then plated with a precious metal based on the following steps. A heat treatment (3 minutes) was performed in the air at 450°C, and the solderability and bonding properties were evaluated.

Example of the present invention (1) Nickel strike plating 0.02μ → gold strike plating 0.02μ → silver plating 0.5μ Comparative example (3) Nickel strike plating 0.02μ → nickel-cobalt alloy 0.5μ → gold plating 061μ → silver plating 0.5μ (5) Gold strike plating 0.02μ → Gold plating 0
．． 1μ (Base material: phosphor bronze) (6) Silver strike plating 0.02μ → Silver plating 0
．． 5μ (base material phosphor bronze) The evaluation results are shown in Table 1. The plating conditions and evaluation method are shown below.

・Nickel strike plating bath composition Nickel chloride 250 g / Q salt
Acid 100g/Q temperature
20℃ Current density 5A/dm” Nickel-cobalt alloy plating (Ni 3 (ht%, Co 70wt%) Bath composition
Nickel sulfate 135 g / Q cobalt sulfate
115g/[Hallic acid 25gIQ Potassium chloride 15g/Q Temperature 406C Current density LA/dm” Nickel alloy plating (Ni 33wt%, Co 67wt%) Bath composition Stannous chloride 50g / QNickel chloride 300
g/Q Sodium fluoride 28 g/Q acidic ammonium fluoride 35 g/Q Temperature 65°C Current density 0.5 A/dm" Gold strike plating bath composition Potassium gold cyanide 2 g/Q
Acid 20gIQ Sodium citrate too
g/Q Room temperature/Strike plating bath composition Silver cyanide 2g/Q Potassium cyanide 100g/Q Room temperature/Gold plated Temperex 701 (product name) made by Kuninaka Precious Metals Temperature
Temperature: 50°C ・5ILVLEX JS-1 (product name) manufactured by Jifc, sold by L-Handanaka Takakai Temperature: 20°C ・Solderability test method After immersing the sample in 25% rosin methanol for 5 seconds, 235
Immersed in a 60/40 (Sn/Pb) solder bath held at ±5°C for 5 seconds, T obtained from the appearance and wetting curve (time until buoyancy becomes 0: the shorter the wetting) The solderability was evaluated based on the results (good solderability).

・Bonding property test - Gold wire of 25 μΦ is placed on the J method sample with a ball at 1 mm intervals.
Wedge bonding was performed, and the bonding properties were evaluated based on the tensile strength.

Margin below Table 1 Solderability and bonding properties x Solderability T2: - No wetting at all.

Appearance condition: 2096% or more of curvature.

X: Showed less than 40% wetting.

*Bonding property 2 - Bonding is not possible.

As shown in Table 1, the inventive example had a temperature of 450°C compared to the comparative example.
It can be seen that soldering after 3 minutes of heat treatment has excellent soldering properties and bonding properties.

(Effects) As described above, the parts for electronic/electrical equipment of the present invention are less likely to deteriorate due to heat (excellent heat resistance), and the noble metal plating can be made thinner, resulting in industrially valuable effects. It is something.

Claims (2)

[Claims] (1) Gold or silver base plating layer on the metal plate, and if the base plating layer is gold plating, then silver or silver alloy plating, and if the base plating layer is silver plating, gold or gold alloy plating. Components for electronic and electrical equipment with layers. (2) The electronic/electric device component according to claim 1, wherein the base plating layer is a gold or silver strike plating layer.