JPH04202064A - Ceramic member-metal member joined body - Google Patents

Abstract

PURPOSE:To obtain a ceramic member-metal member joined body having high reliability by regulating the surface of a ceramic member to be joined to a metal member to prescribed roughness and carrying out brazing. CONSTITUTION:When a ceramic member 1 is brazed to a metal member 2 to form a joined body, the surface of the ceramic member 1 including the joining start point 3 is ground and polished so as to obtain >=100mum surface roughness (average interval Sm between peaks of the surface roughness curve) and <=70% contact ratio TP in the case of 50% cutting level P of the surface roughness curve. The surface roughness curve is made rough by increasing the Sm value and the gradient of the valleys is reduced by reducing the TP value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a joined body in which a ceramic member and a metal member are brazed together.

1 Conventional technology (IIj) In recent years, as mechanical parts used in various industrial machinery under high loads and high temperature atmospheres, lightweight ceramic materials with excellent heat resistance, corrosion resistance and abrasion resistance, and high strength Composite structures that combine metal members with excellent workability have attracted attention, and various joined bodies of ceramic members and metal members have been proposed.

Conventionally, as a joined body of a ceramic member and a metal member,
A metallization treatment is applied to the joint of a ceramic member that has been polished to form a flat or convex portion, and the joint is closely fitted or inserted into the flat or concave portion of the cut metal member for brazing or shrink-fitting. Many zygotes were used.

In particular, when a shaft joint is made of a ceramic member and a metal member, coaxiality of both members is strictly required. Therefore, the fired surface of the part of the ceramic member that is to be joined to the metal member is polished with a diamond grindstone. It was common to do so (see Japanese Patent Application Laid-open No. 155578/1983).

[Problem to be solved by the invention] However, in recent years in the industrial world, the demand for composite structures of ceramic and metal members that have excellent durability under high temperatures has increased year by year, and ceramics polished with a conventional diamond grinding wheel have become increasingly popular. It has been difficult to satisfy this requirement for a joined body using a metal member.

In other words, although the coaxiality between the ceramic member and the metal member can be controlled with relatively high accuracy in the above-mentioned joined body, the joining of the ceramic member and the metal member has a large effect on the strength deterioration of the ceramic member, making it difficult to assemble the joined body. The strength was extremely unstable and lacked credibility.

In particular, when joining a ceramic member and a metal member, the strength of the ceramic member is extremely influenced by the surface roughness and surface texture of the ceramic member. Originally, the surface roughness is rough, and the surface texture is polished. Since the fired surface is more desirable than the surface, in order to achieve coaxiality of both components and maintain the high strength of the ceramic component, a diamond abrasive wheel with comparatively coarse standard diamond abrasive grains fixed with metal or resin is used. After grinding, a polishing finish was further performed using the same diamond grindstone as described above with a fine standard grit of No. 400 or higher.

However, with the polishing described above, many fine grinding marks remain, and it is still not possible to uniformly reduce the stress concentration of the metal member applied to the ceramic member during bonding, and as a result, stable high strength cannot be obtained. There was a problem.

(Means for Solving the Problems j) A joined body of a ceramic member and a metal member of the present invention is a joined body formed by brazing a ceramic member and a metal member.
The surface roughness of the ceramic member including the vicinity of the part of the ceramic member to be joined to the metal member, that is, at least the joining starting point which is the boundary between the joining part and the non-joining part between the ceramic member and the metal member, Average tooth spacing Sm of surface roughness curve
The contact ratio TP value (hereinafter referred to as TP value) when the value (hereinafter referred to as Sm value) is 100 l1m or more and the cutting level P value (hereinafter referred to as P value) of the surface roughness curve is 50% is 7.
It is characterized by being 0% or less.

[Example 1 The present invention will be explained in detail below.

FIG. 1 is a partially cutaway cross-sectional view showing a joined body of a ceramic member and a metal member according to the present invention, and FIG. 2 is a partially cutaway view showing an embodiment in which the joined body of the present invention is applied to a radial rotor. In FIGS. 1 and 2, which are probably fractured cross-sectional views, Lla is the metal member 2° 2a.
3 is a ceramic member soldered to four parts 4 provided at the joint part 5 between the ceramic member 1, 1a and the metal member 2, 2a.
and a joining starting point which is the boundary of the non-joining part 6.

Ceramic members 1, 1a and metal members 2, 2a as described above
In order to ensure the coaxiality of both members and to obtain stable and high strength, the joined body is made of ceramic member 1. The vicinity including the part to be joined with the metal members 2 and 2a of la, that is,
At least the ceramic member 1.1a and the metal members 2, 2a
The joining starting point 3 is the boundary between the joining part 5 and the non-joining part 6.
Ceramic member including 1. The surface roughness of la is polished so that the Sm value of the surface roughness curve is 100 μm or more, and the TP value when the P value is 50% is 70% or less.

Here, the Sm value is calculated from the surface roughness curve of the surface including at least the bonding starting point 3 of the ceramic members 1, 1a measured with a surface roughness meter, and is calculated from the surface roughness curve of the surface including the bonding starting point 3 of the ceramic members 1, 1a.
It is the average value of each interval between the point where the average line of the surface roughness curve intersects within the range (from the peak to the valley) and the point where the average line crosses the surface roughness curve from the next peak to the valley.

Therefore, the larger the Sm value, the rougher the surface roughness curve, which means that the number of peaks and valleys is smaller. Furthermore, the smaller the Sm value, the denser the surface roughness curve, which means that the number of undulations of peaks and valleys is extremely large.

In addition, the TP value is defined as the depth from the highest peak to the deepest valley in L of the surface roughness curve as 100%, and at each position from the highest peak, that is, P%, of the surface roughness curve. The ratio between the total length of crossing the winter mountain and L is expressed as a percentage.

That is, the smaller the TP value at a certain P value, the smaller the slope of the valley, and the larger the TP value, the more extremely large the slope of the valley.

As a result of the above, the reason why the Sm value is large and the GaTP value is small is that the form of the polishing streaks on the surface of the ceramic member has a small number of undulating peaks and valleys, and a small gradient of the valleys. That is,
Accordingly, the number of notches that can become a starting point for fracture of the ceramic member is reduced, and stress concentration as described above is less likely to occur.

Therefore, when the Sm value is 100 μm or more and the TP value is 70% or less when the P value is 50%, and the Sm value is 15
TP value is 50% when it is 0μm or more and P value is 50%
It is more preferable if it is below.

Next, a joined body of a ceramic member and a metal member according to the present invention will be specifically described in detail with reference to an embodiment shown in FIGS. 1 and 2.

(Example 1) The main component is silicon nitride (5i3N4), and itria (Y2O3) and tungsten oxide (tJO) are used as sintering aids.
, ), etc., fired in a nitrogen atmosphere, is first ground using a universal grinder using a diamond whetstone in which diamond abrasive grains coarser than No. 600 are bonded with metal, etc. The outer periphery of the sintered body is ground.

Next, polishing was carried out using a whetstone made of abrasive grains coarser than the No. 400 standard combined with an elastic material under various polishing conditions to form a circle with a diameter of 13 mm and a length of 50 mm as shown in Figure 1. A columnar ceramic member 1 was obtained.

On the other hand, as a metal member, 38% Ni, 15% Co, and the balance F
A nickel-based alloy material consisting of e is used, and the inner diameter is set so that the clearance with the outer diameter of the ceramic member 1 is 10 to 100 μm, and the joint length of the recess 4 with the ceramic member 1 is about 6 mm. A metal member 2 having an outer diameter of 16 mm and a length of 50 n+m was obtained by cutting while matching the actual parts.

Next, after inserting the ceramic member 1 into the metal member 2,
The joint portion was heat-treated and soldered using BAg-8 standard silver solder to obtain a joined body for evaluation.

When the thus obtained joined body of the ceramic member and metal member for evaluation was held, the metal member 2 of the joined body was held in the chuck of the testing machine, and the protruding tip of the ceramic member 1 was pressurized from above to break. The cantilever bending strength value calculated from the load is the required strength σ of the joint. The cantilever bending strength σ at room temperature was evaluated.

The surface roughness of the ceramic member 1 is determined by measuring the surface of the ceramic member 1 before joining with a surface roughness meter so as to include the joining starting point 3 with the metal member 2, and from the obtained surface roughness curve Sm The TP value when the value and P value were 50% was calculated.

FIG. 3 shows a surface roughness curve of a typical ceramic member of the joined body according to the present invention, and FIG. 4 shows a relationship between the P value and the TP value.

In the same manner as described above, a bonded body using a ceramic member polished with a diamond grindstone in which diamond abrasive grains equivalent to the No. 400 standard were bonded with metal or the like was used as a comparative example. FIG. 5 shows the surface roughness curve of the ceramic member of this comparative example, and FIG. 6 shows the relationship between the P value and the TP value.

The above results are shown in Table 1.

(Left below) Table 1 -I O- As is clear from Table 1, comparative examples and Sm values or T
For sample numbers that satisfy only one of the P values,
In both cases, the cantilever bending strength is the required strength σ of the joined body. , the strength of the ceramic member is unstable, whereas the cantilever bending strength of the joined body of the ceramic member and metal member of the present invention exceeds the required strength σ0 of the joined body, and is extremely stable. It was confirmed that bonding was achieved.

In addition, when the center line average roughness Ra and the maximum height Rmax were determined from each of the above-mentioned surface roughness curves measured with a surface roughness meter and compared with the cantilever bending strength, there was no correlation. Large variations in bending strength values were confirmed.

(Example 2) A nickel-based alloy material similar to the above, in which a radial-type low-coupled convex portion 7, which is a ceramic member 1a as shown in FIG. 2 made of a silicon nitride sintered body, is joined to a metal rotating shaft 8. - After fitting into the recess 4 of the metal member 2a consisting of BAg-8
Solder using silver solder equivalent to the standard.

Next, after correcting the balance of the ceramic turbo rotor integrated with the metal rotating shaft 8, a high-speed rotation test at high temperature was conducted to determine the required rotation speed N. The presence or absence of damage to the radial rotor was confirmed, and the damaged rotors were expressed as a multiple of the required rotational speed N0 to evaluate high-speed rotation.

In addition, the surface of the convex part 7 of the radial type rotor before joining is
The surface roughness was measured in the same manner as in Example 1, and the Sm value and TP
I found the value.

As a comparative example, a ceramic radial type rotor polished in the same manner as in Example 1 was joined to a metal rotating shaft.

The above results are shown in Table 2.

(Margins below) = 11- Table 2 main character Kita fii example - 12 = In Examples 1 and 2, the ceramic members were brazed to the metal members without forming a metallized metal layer at the joint portion, but
It has been confirmed that the same results as in Examples 1 and 2 can be obtained even with a bonded body in which a metallized metal layer is formed and soldered.

[Effects of the Invention] As described above in detail, according to the joined body of a ceramic member and a metal member of the present invention, the surface roughness of the ceramic member including at least the joining starting point with the metal member is equal to the surface roughness. Since the Sm value of the curve is 100 μm or more and the TP value is 70% or less when the P value is 50%, combined with the form of the polishing marks on the surface of the ceramic member, the ceramic member is susceptible to repeated stress and thermal stress. In addition to stably securing high strength, it is also possible to achieve highly accurate coaxiality between the ceramic member and the metal member, and it is extremely easy to correct the balance of a rotating body used as a shaft coupling. , a highly reliable joined body of a ceramic member and a metal member can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially broken sectional view showing a joined body of a ceramic member and a metal member according to the present invention, and FIG. 2 shows an example in which the joined body of a ceramic member and a metal member of the present invention is applied to a radial rotor. A partially broken cross-sectional view, FIG. 3 is a diagram showing a surface roughness curve of a typical ceramic member of the joined body according to the present invention,
FIG. 4 is a diagram showing the relationship between the P value and TP value obtained from the surface roughness curve in FIG. 3, FIG. 5 is a diagram showing the surface roughness curve of a ceramic member of a comparative example, and FIG. It is a figure which shows the relationship between the P value and TP value calculated|required from the surface roughness curve of a figure. 1.1a...Ceramic member 2.2a...Metal member 3...Joining starting point

Claims (1)

[Claims] In a joined body formed by brazing a ceramic member and a metal member, the surface of the ceramic member including at least the joining starting point with the metal member has an average pitch Sm of a surface roughness curve.
A joined body of a ceramic member and a metal member, characterized by having a surface roughness of 100 μm or more in terms of value and a contact ratio TP value of 70% or less when the cutting level P value of the surface roughness curve is 50%. .