JPS60162572A - Soldering method - Google Patents

Abstract

PURPOSE:To perform brazing with excellent corrosion resistance without oxdation discoloration in a method for brazing ornamental gold alloy parts to a stainless steel, etc. at <=80 deg.C in a nonoxidizing atmosphere by effecting an eutectic reaction of Ge and gold by using gold solder. CONSTITUTION:A watch case 1 consisting of a stainless steel, Ti, sintered hard alloy, etc. is molded and polished and thereafter the entire surface except the brazing part 4 on the case 1 side is masked in order to braze ornamental gold alloy parts 2. The case is then thoroughly defatted and cleaned and is further activated by electrolytic cleaning and thereafter an electroplating layer 4' of Au, Pd-Ni, Ni, etc. is formed thereon to >=0.5mu thickness and the masking is stripped. On the other hand, Ge powder is dispersed in paraffin and is coated on the brazing surface of the parts 2 to about 20mu thickness and is further subjected to a diffusion treatment by heating in a vacuum to form a diffused layer 3. Such parts 2 are laminated via gold solder 5 on the layer 4' on the case 1 surface and are brazed at 600-800 deg.C in a vacuum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of brazing an Au alloy decorative part to a part of an exterior part.

[Prior art and problems]

Conventionally, for exterior parts made of materials such as stainless steel, Ti, carbide, etc., Au alloy decorative parts were adhered to a part of the exterior part to increase the decorative value and diversify the design. It is.

However, since adhesion has a problem in that the adhesive strength deteriorates due to changes in the adhesive over time, brazing has recently been attempted as a method of joining the exterior component and the Au alloy decorative component. As for the brazing method, it is preferable to braze the parts without causing oxidative discoloration, brazing is performed in a non-oxidizing atmosphere, and the temperature of the brazing is s o
It is required not to exceed o'c.

Ag wax and Au wax are conceivable as brazing materials used for brazing, but Ag wax is prone to oxidation blackening and has problems in corrosion resistance, and Au wax requires a metal phase of 12 or more to satisfy corrosion resistance. The melting point becomes high because it requires 80
It is difficult to braze at temperatures below 0°C.

Therefore, with the conventional brazing method, there is a problem in that it is not possible to braze an Au alloy decorative part to a part of an exterior part with excellent corrosion resistance and without causing oxidation discoloration.

[Purpose of the invention]

The present invention was obtained as a result of experimental studies in view of the above problems, and focused on the fact that Ge and Au undergo a eutectic reaction at a low temperature of 356°C. The gist of the present invention is to provide a method capable of brazing using Au solder at a low temperature of 800 ° C. The purpose of this invention is to provide brazing that does not cause oxidation discoloration and has excellent corrosion resistance when brazing Au alloy decorative parts to exterior parts.

[Structure of the invention]

The structure of the present invention is that when brazing external parts made of materials such as stainless steel, TI, and cemented carbide, the surface is activated, and then Au/Pd-Ni with a thickness of 0.5 μm or more is soldered.
- Brazed at a temperature of 600°C to 800°C in a non-oxidizing atmosphere using an Au alloy decorative part coated with a plating layer such as Ni and pre-brazed with a Ge diffusion layer formed on the surface. This is the way to do it.

To explain the details further, first of all, the reason for brazing the exterior parts is to cover the surface with a plating layer. The strong oxide film of the metal impairs brazing performance, so
The purpose of brazing is to activate the material surface of the part, further protect the active surface from oxidation, and improve properties. As the type of the plating layer, Au11Pd-Ni/Ni plating is suitable in consideration of corrosion resistance and wax flowability.

The reason why the thickness of the plating layer is set to 0.5μ or more is that in order to protect the active surface of the exterior component surface, the thickness of the plating layer must be 0.5μ or more.
This is because sufficient protection cannot be achieved if the thickness is less than μ.

Next, we will talk about the Ge diffusion layer formed on the brazing surface of the Au alloy decorative part.The Ge diffusion layer is formed by applying Ge powder to the brazing surface of the Au alloy decorative part, and then adding A u -G.
This is an Au-Ge eutectic alloy layer formed by performing a diffusion treatment in a non-oxidizing atmosphere at a temperature of 356° C. or higher, which is the eutectic point of e. Its role is to cause the Ge diffusion layer to cause a eutectic reaction with Au, which is the main component of the Au solder, when the Au alloy decorative part and the exterior part to be soldered are brazed with Au solder in a non-oxidizing atmosphere. The purpose is to lower the melting point of the Au wax by raising the temperature.

Next, the reason why the brazing temperature is set at 600°C to 800°C is that the upper limit of brazing needs to be 800°C in order to suppress oxidation discoloration of the exterior parts and Au alloy decorative parts. However, if the temperature is less than 600°C, the diffusion reaction between the Ge diffusion layer and the Au solder is not sufficient, so the lower limit is set at 600°C.

[Embodiments of the invention]

Embodiments of the present invention will be described using the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, FIG. 1 is an exploded perspective view of the brazed front, and FIG. 2 is an exploded perspective view of the stacked cylinder 1.
FIG.
The figure is a perspective view after soldering.

First, the watch side 1 made of 5US304 stainless steel was molded and polished, and in order to braze the 18 kAu alloy decorative part 2, the entire surface of the watch side except for the brazing part 4 was masked. Next, it was thoroughly degreased and cleaned, further activated by electrolytic cleaning, and then a 2 μm Ni plating layer d was formed by electroplating, and then the masking was peeled off.

Some 18kAu alloy decorative parts 2 are soldered with 150% on the surface.
Grind mesh under Ge powder with paraffin to a thickness of 2.
Coated at 0μ and further coated at 600μ in a vacuum of 10=torr.
A Ge diffusion layer 3 with a thickness of 100 μm was formed by performing a diffusion process at 60 m1n at a temperature of 100 μm.

After that, a Ge diffusion layer 6 was formed on the surface of the wax layer 18.
A kAu alloy decorative part 2 is placed on the N1 plating layer 4' of the watch side 10 surface of the 5US304 stainless steel described above.
Laminated through kAu wax 5, then 10-'torr
Brazing was carried out in a vacuum at 750°C and 30M.

As a result, as shown in FIG. 3, the watch side 1 and the 18kAu alloy decorative part 2 were completely brazed together, and no oxidation discoloration was observed, and the soldering retained its previous appearance. In addition, the brazing strength of the rear 1 clock side 1 and the IgkAu alloy decorative part 2 was examined by a peel test, and as a result, the strength was 25 kg/++ufl, indicating sufficient bonding strength. Furthermore, the above watch side was subjected to a 24B test using the JIS ZJ371 salt spray test method.

No rust was observed in the brazed parts, showing good corrosion resistance.

〔Effect of the invention〕

As is clear from the above examples, the brazing method of the present invention can be applied to stainless steel, Ti, etc., which was previously impossible.
It has become possible to braze an Au alloy decorative part to a part of an exterior part made of cemented carbide or the like without causing oxidation and discoloration and with excellent corrosion resistance.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention, Figure 1 is an exploded perspective view of the soldering before, and Figure 2 is an exploded perspective view of the laminated cylinder 1 in the direction of the arrow. FIG. 3 is a cross-sectional view taken along the left side, and FIG. 3 is a perspective view after brazing. 1... Watch side, 2... Au alloy decorative parts, 6... Ge diffusion layer, 4... Brazed portion, 4... ...Plating layer, 5...Au wax. Patent Applicant: Citizen Watch Co., Ltd. Section 1, Section 2, Oral Skills 3 Questions

Claims (1)

[Claims] When brazing exterior parts made of materials such as stainless steel, Ti, and cemented carbide, the surface is activated and then 0.5
Coated with a plating layer such as AumPd-Ni/Ni having a thickness of more than μ, and then coated with the plating layer.For brazing, it is an exterior part, and for brazing, it is an Au alloy decoration with a Ge diffusion layer formed on the surface in advance. This brazing method is characterized by laminating parts and brazing them at a temperature of 600°C to 800°C using Au alloy solder in a non-oxidizing atmosphere.