JPS5916695A - Filler metal containing ceramic fiber - Google Patents

Abstract

PURPOSE:To improve the strength and rigidity of a brazed joint, by incorporating ceramic fibers at a specific rate into a filler metal for brazing. CONSTITUTION:Ceramic short fibers or ceramic whiskers such as aluminasilica short fibers, potassium titanate whiskers, silicon nitride whiskers or the like of <=1mu diameter and <=50mu length are mixed at <=15vol% with a Pb-Sn alloy, Al- Si alloy, Ag-Cu alloy, Cu-Zn alloy, Cu-P alloy, Ag-Mn alloy, etc. to be used as a filler metal for brazing. The joint part brazed by using such filler metal is remarkably improved in strength and rigidity with the presence of the ceramic fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filler metal for a brazing material, and more particularly to a filler metal for a brazing material containing ceramic fibers.

Brazing is a method of joining using a filler metal for brazing that has a lower melting point than the base metal, and generally involves wetting between the solid phase and liquid phase between the base metal and the filler metal without melting the base metal. It joins two base materials by a phenomenon. The filler metals used for this brazing include soft solder that melts at a temperature of 450°C or lower, and hard solder that melts at a temperature of 450°C or higher, including Pb-8n alloy, Zn alloy, and Al-8i alloy. , Cu
Various materials have been used in the past, such as -Zn alloy, Ag-Cu alloy, and Cu-P alloy. The composition of these filler metals for brazing metals is generally limited to a eutectic composition because it is necessary to lower the melting point and improve adhesion with the base metal and corrosion resistance. Compared to filler metals, the strength and rigidity of the joints are very low, and in many cases the creep strength is particularly low. Therefore, there is a problem in that brazing using such a filler metal cannot be used in important parts where high joint strength is required.

Furthermore, since the strength and rigidity of the filler metal for brazing are very low, it is necessary to pay close attention to the joint spacing and overlapping allowance during brazing.

In view of the above-mentioned problems with conventional filler metals for brazing metals, the present invention provides an improved filler metal for brazing metals that has superior strength and rigidity compared to conventional filler metals for brazing metals. The purpose is to

This purpose is achieved according to the invention by using ceramic fibers having a diameter of substantially 1 μm or less and a length of 50 μm or less.
This is achieved by using a filler metal for brazing filler metal containing less than % by volume.

According to the filler metal combined with braze according to the present invention, ceramic fibers as a reinforcing material are mixed in the conventional filler metal combined with braze as a matrix metal, so compared to the case of the conventional filler metal combined with braze. The strength and rigidity of the joint can be improved, and since the composition of the alloy as the matrix metal can be the same as that of conventional filler metals, the melting point is lower than conventional filler metals. The characteristics of low corrosion resistance, excellent adhesion to the base material, and excellent corrosion resistance can be utilized as is.

The alloys as the matrix metal of the filler metal used in conjunction with brazing according to the present invention include Pb-8μ alloy, Al-3i alloy, Ao-Cu alloy, which have been conventionally used as filler metal in combination with brazing.
Cu-, ln alloy, Cu-P alloy, Ao-Mn alloy,
It may be any alloy such as Cu-AL+ alloy, Zn-A1 alloy. Ceramic fibers added as reinforcing materials to these alloys have excellent compatibility with any of these alloys, and therefore ceramic fibers and matrices as reinforcing materials in brazed joints are suitable. Adhesion to metal alloys can be improved. Furthermore, according to the results of experimental research conducted by the inventor of the present application, if the diameter of the ceramic fiber is 1μ or more and the length is 50μ or more, brazing becomes difficult. It is preferable to use ceramic short fibers such as alumina-silica short fibers, potassium titanate Boyce, silicon nitride Boyce, or ceramic Boyce, which have a length of 1μ or less and a length of 50μ or less. Furthermore, when the ceramic fiber content is 15% by volume or more, the strength of the joint increases, but the fluidity of the filler metal used with the brazing material decreases,
Since brazing becomes difficult, the content of ceramic fibers is preferably 15% by volume or less.

The filler material combined with brazing according to the present invention is obtained by melting a conventional filler metal combined with brazing in a crucible or the like, and in the melted filler metal, ceramic [t] is substantially oriented in a three-dimensionally randomly oriented state. It may be manufactured by mixing ceramic fibers into the molten filler material while stirring the molten filler material so that it is uniformly dispersed, and solidifying it in a predetermined shape and size. .

The present invention will be described in detail below with reference to Examples.

E1 Solder traditionally used for craftsmanship (50%Pb-50%S)
By adding potassium titanate voice force to n), a filler metal used in combination with brazing material having high joint strength was manufactured. The potassium titanate voice used was manufactured by Otsuka Chemical Co., Ltd.
It was Tismo DJ (trade name) and had the characteristics shown in Table 1 below.

Table 1 Diameter 0.1~0.3μ Length
20-30μ elastic modulus 28'
O'O'OkO/ m1 intensity
7 'O'Oko/mm9 The properties of the filler metal combined with brazing according to this example and the conventional solder as a comparative example are shown in Table 2 below.
Shown below. In addition, 5- In Table 2, the volume ratio indicates the volume ratio of potassium titanate voice force as a reinforcing material, and the joint strength is the volume ratio when two copper plates are stacked and brazed at the fillet. It shows the shear strength of the joint in the direction of the plate surface.

Table 2 Invention Comparative Example Composition 50%p b-50%3n 50%p b-
50%Sn+K2TiO, Whisker volume fraction 10% O% Melting point
224℃ 224℃ Strength
5. 5ko/+v+Q 4. 2ka/mm
11 From Table 2, it can be seen that the shear strength of the brazed joint can be improved without increasing the melting point of the solder by using the filler metal used in combination with brazing according to this example.

Although it is not shown in Table 2, the magnitude of the added potassium titanate voice force is small, and its volume fraction is also low. , adhesion to the base material, brazing workability, etc. were substantially the same as those of the comparative example.

Example 2 Traditionally used Al-3i filler metal L
By adding silicon carbide voice force to IIS standard BAI-4+AI-12%Si), a filler material combined with brazing and having high joint strength was produced, as in the case of Example 1 described above. The silicon carbide voice force used had the characteristics shown in Table 3 below.

Table 3 Diameter 0. 2-0. 5μ length 15~40μ elastic modulus 49
0'0'Okg/mm2 Strength
21 'O'Okg/nun' The properties of the filler metal combined with brazing according to this example and the conventional filler metal combined with brazing as a comparative example are shown in Table 4 below. In Table 4, the volume fraction indicates the volume fraction of silicon carbide whiskers as a reinforcing material, and the strength indicates the volume fraction of silicon carbide whiskers as a reinforcing material.
It shows the tensile strength in the plate surface direction of the joint when torch brazing is performed by butting 100P).

Table 4 Present invention Comparative example composition Al-12%Si At-12%S1
+ Sac whisker volume fraction 5% 0% melting point
58'O℃ 58'O℃ strong
degree 9. 5ko/mm2 6. 2kg
/+ua9 From this Table 4, it can be seen that the tensile strength of the brazed joint can be significantly improved by using the filler metal combined with brazing according to this example without causing an increase in the melting point of the filler metal combined with brazing. I understand. Although not shown in Table 4, as in Example 1 above, the fluidity of the filler metal combined with brazing, the adhesion to the base material, the workability of brazing, the corrosion resistance of the joint, etc. It was substantially equivalent to the comparative example.

Although the present invention has been described in detail with reference to two embodiments above, the present invention is not limited to these embodiments, and various embodiments are possible within the scope of the present invention. will be clear to those skilled in the art.

Patent applicant: Toyota Motor Corporation representative
Patent attorney Masa Akashi
Tsuyoshi 9-

Claims (1)

[Claims] A filler material for a brazing filler metal containing 15% by volume or less of ceramic fibers having a diameter of 1 μm or less and a length of 50 μm or less.