JPH06183851A - Soldering pretreatment of ceramic - Google Patents

Abstract

PURPOSE:To provide a pretreatment method for firm joining of ceramic parts. CONSTITUTION:Prior to soldering a pair of ceramics or a ceramic and a metal, one of Ti, Zr or Al is vacuum-evaporated to form a film coat on a soldering surface of the ceramic and subsequently a film of Cu or Au is overlaid on the film coat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment method for joining ceramic members, and more particularly to a pretreatment method for ceramics in brazing and joining ceramics and ceramics and ceramics and metal.

[0002]

_2. Description of the Related Art Conventionally, Si ₃ N ₄ , Al ₂ O ₃ and ZrO have been used.
_In brazing ceramics such as ₂ and ceramics or ceramics and metal, an active metal such as Ti, Zr, Al or an alloy containing these active metals is used as a brazing material. This brazing material is generally inserted into the joint surface as a powder or a thin plate.

[0003]

The wettability between the ceramics and the molten metal, that is, the brazing filler metal is smaller than that of the metal and the molten metal, and a bonding defect is likely to occur. Therefore, generally, a metallizing method such as Mn-Mo method (metallizing method in which powders of Mo and Mn are heated and fired at about 1500 ° C. in a hydrogen atmosphere containing water vapor) is used, but in a humidified hydrogen atmosphere at 1500 ° C. or higher. Many complicated steps such as heating are required, and this method cannot be applied to Si ₃ N ₄ etc., and the applicable range is limited. That is, for the Si ₃ N _4, decomposition or oxidation caused the Si ₃ N ₄ during heating and firing at about 1500 ° C., because the surface layer the Si ₃ N ₄ will be altered.

In view of the above-mentioned state of the art, the present invention is a pretreatment of ceramics capable of firmly bonding ceramics and ceramics or ceramics and metal by brazing without causing the problems of the prior art. It is intended to provide a method.

[0005]

The present invention, when brazing ceramics and ceramics or ceramics and metal, forms a film on the brazing surface of the ceramics by vapor deposition of one of Ti, Zr or Al, Then, a method for pre-brazing ceramics is characterized in that a Cu or Au film is formed on the same film.

That is, the present invention is based on Si ₃ N ₄ , Al ₂ O
Ti, Zr on the joint surface of ceramics such as ₃ , ZrO ₂
Alternatively, a ceramic pretreatment is performed by forming a film of Cu or Ag after forming a film of one active metal of Al by a high vacuum process to form a metallized layer having a two-layer structure.

At this time, immediately after forming the active metal, Cu is formed.
Alternatively, a film of Ag is formed, or a binary vapor deposition or a binary sputtering device is used in the latter stage of formation of the active metal layer, and then Cu or Ag is also formed into a film to form a mixed layer between the active metal layer and the Cu or Ag layer. It is desirable to do.

As the brazing material, in addition to general Ag brazing system and Ni brazing system, Cu-Ti system, Cu-Cr system, Cu-Zr system
A type, Al, Al-Si type may also be used.

[0009]

[Function] The active metal of Ti, Zr or Al is formed as the first layer because it has excellent adhesion to ceramics and does not cause peeling, and it reacts with ceramics during brazing to form a reaction product, which is strong. This is because a high joining strength can be obtained.

The reason why the Cu or Au film is formed on the active metal is to improve the wettability with the brazing material. That is, in the metallization of only the active metal, the surface of the active metal is oxidized when taken out into the atmosphere, and TiO ₂ , ZrO ₂ , Al ₂
This is because a ceramic layer of O ₃ or the like is formed and the wettability becomes poor.

In addition, starting the formation of Cu or Ag immediately after forming the active metal or at the latter stage of forming the active metal suppresses the oxidation of the surface of the active metal layer as much as possible, and the active metal layer and Cu or Ag are formed.
This is because the adhesiveness with the layer is not deteriorated. (Even in a vacuum, if an oxygen partial pressure exists, the active metal will be oxidized.)

According to the method of the present invention, after forming Ti, Zr or Al having an excellent adhesive force as an intermediate layer, Cu and Ag, which are exfoliated when they are directly formed on the ceramic, are formed. It is intended to improve and prevent the occurrence of defects during joining.

[0013]

EXAMPLES Table 1 collectively shows various examples of the present invention.
The metal layer was formed on the ceramic plate by vacuum vapor deposition. The conditions of vacuum vapor deposition were such that the metal was melted and evaporated using an electron gun under a pressure of 5 × 10 ⁻⁵ Torr. The ceramic base material was heated to 200 ° C. by a heater. The surface roughness of the ceramic substrate is 0.8 S or less for Si ₃ N ₄ and Al
₂ O ₃ and ZrO ₂ were used after being polished to 1.5 S or less. (In addition, S is a unit of surface roughness, JIS B
According to Table 1 of 0659-1973. ) Also Al ₂ O ₃
Was a 99.99% high-purity sintered body containing almost no sintering aid.

The adhesion was evaluated by a peeling test using cellophane tape, and those which did not peel off were judged to be acceptable (marked with a circle).

A wettability of 100 μm × 15 mm × 15 mm silver braze (component: 70% Ag-28% Cu-2% Ti) foil was placed on the surface of the metallized ceramics and 5 × 10 ⁻⁴
The spread area of the brazing filler metal after heating and melting at 900 ° C. under a pressure of Torr and holding for 30 minutes was evaluated. That is, as the initial brazing material foil area A ₀ (15 mm × 15 mm = 225 mm ² ) and the brazing material spreading area A after heating, A / A ₀ > 1.1 is considered to have good wettability. It was judged and passed (marked with ○). The size of the ceramic substrate is 25 mm × 25 mm
Therefore, A / A ₀ was displayed as> 2.9 although it spread over the entire surface.

From the above, it is necessary to form an active metal layer in order to obtain the adhesion between the metallized layer and the ceramic substrate, but the surface of the active metal layer forms a stable oxide layer by being exposed to the atmosphere, Since the wettability is not improved, it was found that it is effective to further form a metal layer of Cu, Ag or the like on it. The pressure during the wettability test is 5 × 10
^{At -4} Torr, the oxygen partial pressure is high, and the active metal surface is further oxidized during the wettability test.
^It was also carried out at ^-6 Torr, but interference color due to the transparent oxide layer was observed, and it was also found that the wettability could not be improved by further growth of the surface oxide layer even when used under a high vacuum even if the active metal layer was used alone.

Table 1 shows the case of brazing ceramics and ceramics. Since metal is better than ceramics, those having good wettability with ceramics are also good for brazing with this type of metal.

[Table 1]

[0018]

According to the method for pretreating ceramics of the present invention, when brazing ceramics and ceramics or ceramics and metal, the wettability of the brazing material can be improved, and a good bonded body of ceramics and ceramics or ceramics and metal can be obtained. Obtainable.

Claims (1)

[Claims] 1. When brazing ceramics and ceramics or ceramics and metal, a film is formed on the brazing surface of the ceramics by vapor deposition of Ti, Zr or Al, and then Cu or Cu is formed on the film. A method for pre-brazing ceramics, which comprises forming a film of Au.