JPH10182257A - Ceramics-metal joined member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To tightly join a ceramic member made of titanium boride or silicon carbide to a metallic member, to relieve residual stress produced by the difference in thermal expansion between the members and to relieve thermal stress and mechanical stress produced at the time of joining in the joined part by interposing a specified bonding metal between the members. SOLUTION: A ceramic member made of titanium boricle or silicon carbide is joined to a metallic member with Al or Zn as a bonding metal in-between. The metallic member may be made of any of metals ranging from a metal having a relatively low coefft. of thermal expansion, e.g. 'Kovar(R)' or 42Ni alloy to a metal having a relatively high coefft. of thermal expansion, e.g. austenitic metal. The bonding metal is interposed between the members preferably in 0.03-0.3mm and they are heated at the m.p. of the bonding metal, or above in vacuum to obtain the objective ceramics-metal joined member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic-metal joining member applicable to various industrial products such as mechanical parts.

[0002]

2. Description of the Related Art Generally, ceramics are superior in heat resistance and abrasion resistance as compared with metal materials. Therefore, utilization of ceramics in various fields such as wear-resistant products such as mechanical parts has been attempted. However, ceramics have high hardness, but have insufficient toughness and mechanical strength, and have poor mechanical workability.Therefore, replacing ceramics with the entire product poses problems in terms of reliability and price. is there. For this reason, a ceramic material is used only for a necessary portion, and the other portion is combined (joined) with a metal material to utilize the characteristics of both materials.

Conventionally, as a means for connecting the metal member and the ceramic member, methods such as screwing, shrink fitting, brazing and the like have been known. However, the method using screwing has problems in bonding strength, adhesion and sealing properties, and the use conditions are limited. Further, in the shrink fitting method or the brazing method, residual stress is generated in the ceramic member and the metal member due to a difference in thermal expansion between the ceramic and the metal, and the ceramic member may be damaged in some cases. In particular, in the case of brazing, joining using a Kovar alloy or a 42Ni alloy having a low coefficient of thermal expansion as a metal member was considered, but the coefficient of thermal expansion of these low thermal expansion metals rapidly increases at about 400 ° C. or higher. . For this reason,
Joining using a silver brazing material having a melting point of 700 to 900 ° C. causes a problem of residual stress similarly to a normal metal member.

Accordingly, Japanese Patent Publication No. 7-37346 discloses 70
Extremely small joint strain by reducing the difference in expansion and contraction displacement of metal by utilizing the hysteresis due to transformation of metal and brazing material having a solidus point of 0 ° C. or less (temperature at which all liquid brazing material becomes solid). It is disclosed to obtain a joining member. However, it is necessary to heat-treat the metal member used for the joining member, and it is necessary to control the cooling rate during the subsequent cooling. Further, there is a problem that the material (composition) of the metal member used for the joining member is restricted.

[0005] Japanese Patent Publication No. 6-49623 and Japanese Patent Publication No. 7
Japanese Patent Publication No. 110794 and Japanese Patent Publication No. 7-110795 disclose a method for joining a ceramic member and a metal member via a stress relaxation layer or the like.
However, these methods are particularly difficult to apply to those having a large joining diameter because the difference in shrinkage during joining cooling cannot be absorbed. In addition, the use of the stress relaxation layer increases costs.

In Japanese Patent Publication No. 7-55868, a fiber-reinforced plastic material is interposed between a ceramic member and a metal member in order to suppress residual stress inside the ceramic member.
A joining member in which both members are joined is disclosed. However, since the inclusion used as the intermediate layer is a fiber-reinforced plastic, this joining member has poor heat resistance,
Can not be used above ℃.

[0007] JP-A-6-172052, JP-A-6-1
No. 72053 discloses that in the press-fit joining of a ceramic member and a metal member, a surface treatment or a lubricant is applied near the fitting end to reduce the friction coefficient, and then the ceramic member is pressed into the metal member and the press-fit surface is heat-treated. Thus, a method of manufacturing a joining member in which a slipping action is reduced to improve a coupling holding force is disclosed. However, this joining member has a problem that the tensile strength (pulling strength) between the ceramic member and the metal member is low.

Further, the ceramic member and the metal member are made of an alloy (Sn—Zn, Pb—In) having a melting point of 200 ° C. or more.
System, Sn, Pb, Pb-Ag system, Cd-Ag-Sn system,
Sn-Ag-Cu system, In-Au system) or silver brazing (A
g-Cu system, Ag-Cu-Sn system, Ag-Cu-Zn
(Ag-Cu-In-based, Ag-Cu-Sn-based). However, when a ceramic member made of titanium boride (TiB ₂ ) or silicon carbide (SiC) is used in such a joining member,
A main component or an additive component in the brazing material reacts with the ceramic to easily form a reaction layer at a bonding interface. When such a reaction layer is formed at the joint interface between the ceramic member and the metal member, it is difficult to reduce the stress applied to the joint interface, which causes a crack or the like in the ceramic member. In addition, metals such as Cd, Pb, Sn, and In are generally harmful, and require careful precautions in handling, and have environmental problems.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a ceramic member and a metal member are firmly joined, and a residual stress generated by a difference in thermal expansion between the members can be reduced. An object of the present invention is to provide a ceramic-metal joining member capable of relieving mechanical stress at a joining portion.

[0010]

SUMMARY OF THE INVENTION A ceramic-metal joining member according to the present invention comprises a ceramic member formed by joining a ceramic member made of titanium boride (TiB ₂ ) or silicon carbide (SiC) and a metal member via a bonding metal. -In the metal bonding member, the bonding metal is made of aluminum or zinc.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The ceramic-metal bonding member according to the present invention is a material in which a ceramic member made of titanium boride (TiB ₂ ) or silicon carbide (SiC) and a metal member are extremely reactive in a molten state to aluminum (melting point: about 660 ° C.) or It is joined via a bonding metal made of zinc (melting point: about 420 ° C.).

As the above-mentioned metal, an austenitic metal having a relatively large coefficient of thermal expansion such as a Kovar alloy or a 42Ni alloy having a relatively small coefficient of thermal expansion can be used.

The thickness of the bonding metal interposed at the bonding interface between the ceramic member and the metal member is 0.03 to 0.3.
mm is preferable. Set the thickness of the bonding metal to 0.
If the thickness is less than 03 mm, it becomes difficult to sufficiently increase the bonding strength between the ceramic member and the metal member. On the other hand, if the thickness of the bonding metal exceeds 0.3 mm, the bonding strength may be reduced. More preferred thickness of the bonding metal is
It is 0.05 to 0.25 mm.

Next, a method of manufacturing a ceramic-metal joining member according to the present invention will be described. Titanium boride (TiB
₂ ) or after a bonding metal made of aluminum or zinc is interposed on a bonding surface between a ceramic member made of silicon carbide (SiC) and a metal member, and then heat-treated in a vacuum at a temperature higher than the melting point of the bonding metal. A ceramic-metal joining member is manufactured by joining a ceramic member and a metal member with the bonding metal.

It is preferable that the joining surface of the ceramic member is cleaned with an organic solvent such as acetone. Preferably, the metal member is plated with Ni to improve the wettability with the bonding metal.

It is preferable that the bonding metal is interposed in a state of powder or a thin plate at a joining surface between the ceramic member and the metal member. The degree of vacuum in the bonding step is 1
It is preferable to set it to 0 ^-4 Torr order or less. If the degree of vacuum at the time of joining is set to 10 ^-3 Torr or more, the bonding metal may be oxidized at the time of joining, and the joining strength between the ceramic member and the metal member may be reduced. A more preferable degree of vacuum is 10 ^-4 to 10 ^-6 Torr.

The heating temperature is preferably 710-810 ° C. when Al is used as the binding metal, and 470-570 ° C. when Zn is used as the binding metal. The ceramic-metal joining member according to the present invention described above is made of aluminum (melting point: about 660) having a very low reactivity in a molten state between a ceramic member made of titanium boride (TiB ₂ ) or silicon carbide (SiC) and a metal member. ° C) or zinc (melting point: about 420 ° C) via a bonding metal. Such a ceramic-metal joining member has the following functions and effects.

(1) Low melting point aluminum (melting point: about 660 ° C.) or zinc (melting point: about 420) as a bonding metal
° C), a ceramic-metal bonding member can be obtained by a bonding process at a lower temperature than silver brazing.

That is, the residual stress generated due to the difference in thermal expansion between the ceramic member and the metal member can be reduced. Further, the metal member can be widely used from the above-described one having a relatively small coefficient of thermal expansion (a Kovar alloy or a 42Ni alloy) to a large one (such as an austenitic alloy).

(2) Since aluminum or zinc having high ductility is used as the bonding metal, the thermal stress generated at the time of joining can be reduced by the bonding metal layer itself. Also,
Even when mechanical stress is applied during use, the mechanical stress can be reduced by plastic deformation of the bonding metal. As a result, it is possible to prevent cracks and cracks from being generated in the ceramic member having the brittle property compared to the metal.

(3) The bonding metal (aluminum or zinc) in the molten state during the bonding process is TiB ₂ or S
The reactivity with the ceramic member made of iC is extremely low, and the formation of a reactant at the interface between the ceramic and the bonding metal after the heat treatment can be prevented. As a result, for example, a cylindrical ceramic member 4 having a through hole 3 at the center is inserted into a bottomed cylindrical metal member 2 having an opening 1 at the bottom as shown in FIG. When a mechanical stress is applied to the bonding interface in the ceramic-metal bonding member bonded by the layer 5, a displacement occurs at the bonding interface between the ceramic member 4 and the bonding metal layer 5 as shown by an arrow in FIG. 1. The mechanical stress can be reduced.

On the other hand, in the joining by silver brazing and the joining using a brazing material having a low melting point, a reaction product is generated by a chemical reaction at the joining interface between the brazing material and the metal member or the ceramic member, and a stronger material is obtained. Be combined. As a result, even if a mechanical stress is applied to the bonding interface, it is difficult to relax the stress at the bonding interface due to displacement.

The characteristics of the ceramic-metal bonding member according to the present invention, the ceramic-metal bonding member manufactured by silver brazing, and the ceramic-metal bonding member manufactured by shrink fitting are shown in Table 1 below. .

[0024]

[Table 1]

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail. Embodiments 1 to 6 In the embodiments 1 to 6, the SU shown in FIG.
S304 or 42Ni alloy.
The jig 11 which has been subjected to the plating process is provided with TiB ₂ shown in FIG.
Ceramics (trade name: TiB, manufactured by Toshiba Ceramics Corporation)
X) or a test for joining the ring 12 made of SiC ceramics (trade name: CERAIC-B, manufactured by Toshiba Ceramics Co., Ltd.).

First, the ceramic ring 1 shown in FIG.
2 was washed in acetone for about 5 minutes. Subsequently, a ceramic ring 12 shown in FIG. 3 is inserted into a jig 11 whose inner peripheral surface side shown in FIG. 2 is Ni-plated, and aluminum powder (purity 98%) as a bonding metal is inserted into a gap between joints of these members. After filling with Zn powder (purity 98% or more, particle diameter 50 μm or less) or Zn powder (particle diameter 50 μm or less), 10 ⁻⁴
In a vacuum of the Torr order, the melting point of the binding metal +
It was kept at a temperature of about 50 ° C. for 10 minutes, and then allowed to cool in a furnace to produce six types of ceramic-metal joining members.

(Comparative Examples 1 to 6) TiB ₂ ceramics (trade name: TiBX, manufactured by Toshiba Ceramics Co., Ltd.) or Si
C ceramics (Toshiba ceramics product name: CER
ASIC-B) shown in FIG.
Was washed in acetone for about 5 minutes. Subsequently, the inner peripheral side surface of the jig 11 having the shape shown in FIG. 2 and having the inner peripheral side surface made of SUS304 or 42Ni alloy plated with Ni is coated with a silver brazing material paste (silver brazing material powder; After coating with a silver brazing thin plate having a thickness of 50 μm or less and a thickness of 55 μm, a ceramic ring 12 whose outer peripheral surface is metallized as shown in FIG. 3 is inserted, and about 850 in a vacuum of the order of 10 ⁻⁴ Torr. It was kept at a temperature of 10 ° C. for 10 minutes and then allowed to cool in a furnace, thereby producing six types of ceramic-metal joining members.

The states of the rings of the obtained metal-ceramic bonding members of Examples 1 to 6 and Comparative Examples 1 to 6 were observed. The results are shown in Table 2 below. Table 2 also shows the joining conditions, the thickness of the brazing material layer (bonding metal layer), and the like.

Further, the ring surface and the cross section of the metal / ceramic bonding members of Comparative Examples 2 and 4 were observed. as a result,
(A) and (b) of FIG. 4 [Comparative Example 2], (a) of FIG.
(B) Ceramic ring 1 as shown in [Comparative Example 4]
It was confirmed that a number of cracks 13 were generated in No. 2.

[0030]

[Table 2]

(Examples 7 to 12) In order to evaluate the bonding strength, as shown in FIG. 6, a screw hole 31 is provided at one end of both ends, and the other end has an outer diameter of 4.5 mm and an inner diameter of 3.7 mm. Two joints 33 made of SUS304 or S45C having the connection cylinder 32 of No. 3 were prepared. Subsequently, as shown in FIG. 7, the connecting cylinder 32 of one joint 33 has an inner diameter of 3.5 mm and a length of 30 mm.
After inserting one end of a rod 34 made of TiB ₂ or SiC ceramics having a thickness of 0.1 mm, aluminum powder (purity 98% or more, particle diameter 50 μm or less) or Zn powder (purity 98% or more, particle diameter 50 μm or less). After inserting the other end of the rod 34 into the connecting cylinder 32 of the other joint 33, aluminum powder (purity of 98% or more, particle size of 50 μm or less) or Zn powder (purity of 98% or more) is inserted between the joint and the rod. , A particle size of 50 μm or less). Next, these joints and rods are held in a vacuum of the order of 10 ^-4 Torr at a temperature of the melting point of the bonding metal + about 50 ° C. for 10 minutes, and then allowed to cool in a furnace to thereby obtain six types of ceramic-metal bonding. Test pieces were manufactured.

(Comparative Examples 7 to 10) Example 7 was repeated except that the joint and the ceramic rod were joined using a thin silver brazing material.
Four kinds of ceramic-metal bonded test pieces were manufactured in the same manner as in Nos. 1 to 12.

The obtained Examples 7 to 12 and Comparative Examples 7 to
After screwing the hooks 35 into the screw holes 31 of the joints 33 on both sides of the ten ceramic-metal joint test pieces (five each) as shown in FIG. 8, a strength tester (AG-2000C) manufactured by Shimadzu Corporation , Tensile stress was applied through the hooks, and the tensile strength was measured. The results are shown in Table 3 below as an average value of five samples. Table 3 below
Indicates the joining conditions, the thickness of the brazing material layer (bonding metal layer), and the like.

[0034]

[Table 3]

(Examples 13 to 16, Comparative Examples 11 to 14)
Joint members of Examples 1-4 and Comparative Examples 3-6 (5 each)
The value of the residual stress generated on the ceramics side from the vicinity of the bonding interface to the center was measured by the IF method. The results are shown in Table 4 below. Here, utilizing the fact that the fracture toughness value of ceramics apparently changes in the presence of residual stress, the fracture toughness value is determined by the IF method (method determined from Vickers indentation), and the residual stress at that time is determined. The residual stress was calculated from the following equation (1), which calculates back.

K _c = K _c ^* + 2Yσ a / π (1) K _c : Fracture toughness without residual stress K _c ^* : Apparent fracture toughness a: Length of crack generated from four corners of indentation : Residual stress Y: Constant

[0037]

[Table 4]

As shown in the examples of Tables 2 to 4, the ceramic-metal bonding member obtained by bonding the ceramic member made of TiB ₂ or SiC and the metal member of the present invention has a relatively high temperature such as silver brazing. Since the treatment at a lower temperature can be performed than that bonded by the method described above, the value of the residual stress is also reduced.

Further, in the ceramic-metal joining member of the present invention, since the mechanical stress can be relieved by the bonding metal layer, breakage of the ceramic member is extremely reduced. Furthermore, the bonding strength of the ceramic-metal bonding member of the present invention is comparable to or slightly superior to that of a normal silver brazing bonding member, and the bonding strength of an organic adhesive or a reinforced plastic material as an intermediate layer in terms of heat resistance is also high. Because it is far superior to the body, it can be used in a wide range.

[0040]

As described above in detail, according to the present invention, the ceramic member and the metal member are firmly joined, and the residual stress generated due to the difference in thermal expansion between the members can be reduced. It is possible to reduce the thermal stress and mechanical stress that occur at the joint, and to provide a ceramic-metal joint member applicable to various industrial products.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a stress relieving action of a ceramic-metal joining member of the present invention.

FIG. 2 is a cross-sectional view showing a jig used in Examples 1 to 6 and Comparative Examples 1 to 6 of the present invention.

FIG. 3 is a sectional view showing a ceramic ring used in Examples 1 to 6 and Comparative Examples 1 to 6 of the present invention.

FIG. 4 is a view showing a state of a ceramic ring in a ceramic-metal bonding member of Comparative Example 2.

FIG. 5 is a view showing a state of a ceramic ring in a ceramic-metal bonding member of Comparative Example 4.

FIG. 6 is a sectional view showing a joint used in Examples 7 to 12 and Comparative Examples 7 to 10.

FIG. 7 is a cross-sectional view showing ceramic-metal bonded test pieces bonded in Examples 7 to 12 and Comparative Examples 7 to 10.

FIG. 8 is a diagram showing a state in which a hook is screwed on a ceramic-metal bonded test piece joined in Examples 7 to 12 and Comparative Examples 7 to 10 in order to measure tensile strength.

[Explanation of symbols]

 Reference numeral 2 denotes a metal member, 4 denotes a ceramic member, 11 denotes a jig, 12 denotes a ceramic ring, 33 denotes a joint, 34 denotes a ceramic rod, and 35 denotes a hook.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuji Kojima 1 Minamifuji, Ogakie-cho, Kariya-shi, Aichi Pref. Toshiba Ceramics Co., Ltd. Kariya Works

Claims (1)

[Claims] 1. A ceramic-metal bonding member in which a ceramic member made of titanium boride or silicon carbide and a metal member are bonded via a bonding metal, wherein the bonding metal is made of aluminum or zinc. -Metal joining members.