JPH0333074A - Ceramics-al brazed structure and production thereof - Google Patents

Abstract

PURPOSE:To obtain a ceramics-Al brazed structure having superior corrosion resistance to Na and superior durability to temp. rise and drop by interposing a brazing filler metal obtd. by adding Si to Al between a ceramic member and an Al member having specified Al purity or above and brazing the members under pressure. CONSTITUTION:A brazing filler metal 2 obtd. by adding Si to Al, e.g. an Al-Si or Al-Si-Mg alloy is interposed between a ceramic member 1, e.g. an alumina ring and an Al member 3 having >=98wt.% Al purity, e.g. a metal fitting on piping side. The members 1, 3 are then brazed under pressure, fine Si grains are deposited on the interface between the ceramic member 1 and the brazing filler metal 2 and Si is uniformly diffused in the metal 2 and the joint between the metal 2 and the Al member 3 so that the density is gradually lowered toward the Al member 3. A ceramics-Al brazed structure is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic and aluminum (Al) brazed assembly and a method for manufacturing the same.

[Prior art] Ceramic and aluminum (Al) tin @ ellipse is
For example, it is used in the flange of a heat exchanger that uses sodium as a heat medium. In this flange part, the heat exchanger side metal fitting and the l'i & side metal fitting are joined via alumina,
The alumina ring, the heat exchanger side metal fittings, and the piping side metal fittings are pressure brazed via an intermediate joining ring made of Al as a soldering material.
An Al-gold alloy with a purity of 98% or less, such as A3003 or A6061, was used.

[Problems to be Solved by the Invention] However, since the conventional heat exchanger side metal fittings and piping side metal fittings had an Al purity of 98% by weight or less, the connection between the alumina ring and the heat exchanger side metal fittings and the piping side metal fittings was poor. The joint strength is low, and the corrosion resistance against sodium (Na) is poor.
Moreover, it is susceptible to temperature changes such as temperature rise and fall, and has low durability as a flange portion of a heat exchanger.

This can be inferred as follows based on EPMA surface analysis and FIG. 5, which shows an enlarged view of the joint between the alumina ring and the metal fitting on the heat exchanger side. When A3003 Al alloy is used for the heat exchanger opening tool 3 and the piping side fittings 5, silicon (Sl) sufficiently migrates to the interface between the intermediate joint ring 2 (soldering material) and the alumina ring 1 (α-Al20s). Therefore, the bonding force that is thought to be caused by the presence of Si is weak, resulting in poor bonding strength. Although this insufficient movement of Si particles has not been elucidated, it is presumed that the elements contained in Al, represented by manganese (Mn) in A3003, have some influence.

In addition, in the case of A3003, wide pure Al is formed in the intermediate bonding rings 2 and 7 (soldering material), and S1
Particle diffusion is non-uniform and large Si particles are also present in the structure. Like this Alj! Both the width of l and the distribution of 81 particles are very non-uniform, which seems to reduce the bonding strength.

The purpose of the present invention is to increase the bonding strength between ceramic parts and Al parts, and to increase the rK resistance against Na.
It is an object of the present invention to provide a soldered Ia body of ceramics and Al, which can improve corrosion resistance and natural cycleability, and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention is a ceramic component in which an Al component is bonded to a ceramic component using a brazing material in which Sl is added to Al.
Measures are being taken to increase the degree of oxidation to 98.0% or higher.

It is preferable that the solder material is an Al-3L alloy.

The brazing material is mainly composed of Al, 6 to 13% Si, 3
! Al containing less than i% Mg and other unavoidable impurities
-Si-Mg alloy is preferable.

The ceramic part contains 75% by weight or more of α-A j
It is best to set it to 20 seconds.

In addition, this invention has ceramic parts and Al purity of 98.
A brazing material in which Si is added to Al is interposed between the aluminum parts containing 0% by weight or more, and they are pressure brazed, and fine particles of Si are grown at the bonding interface between the ceramic parts and the soldering material. , apply Si uniformly to the brazing and the joints between it and the Al parts,
In addition, a method is adopted in which the aluminum is diffused into the parts so as to become thinner.

[Function] This invention is A! for Al parts! Since the linear purity is 98.0% by weight or more, the diffusion of Sl becomes gradually thinner and uniform as it moves away from the interface between the solder material and the ceramic part toward the Al part inside the solid material, and Si particles are present at the interface. Since it is generated almost uniformly and the bond is strong, the bond strength between ceramic parts and A-O parts is improved, and Na
Corrosion resistance and heat cycle resistance of the joints are improved.

[Example] Hereinafter, the present invention will be described with reference to the drawings regarding a metal-ceramic bonded structure having a flange side passage portion.

As shown in Fig. 1.2, the lower end surface 1a and upper end surface 1b of the alumina ring 1 as a ceramic component are connected to intermediate bonding rings 2 and 4 made of an Al alloy, which is a steel material in which Si is added to Al. The seven run portions 3a and 5a of the heat exchanger side metal fitting 5 and the piping side metal fitting 3 as Al parts are fixed by a pressure brazing method which will be described in detail later.

The purity of the alumina forming the alumina ring 1 is 75.
% or more. Further, the Al alloy of the intermediate joining ring 2 has Al as a main component, Si: 6 to 13% by weight, Mg: 3
．． Al-3 containing 0% by weight or less and other unavoidable impurities
It is made of L-Mg alloy.

The Al parts contain unavoidable trace impurities Si, Fe, Cu, Mn, Mg, Cr, Zn, in the weight percentage shown in Table 1.
Contains Ti etc.

(Left below) Next, we will arrange the alumina ring 1 based on Figure 1. 1Tl
A method of pressure brazing the II fitting 3 and the heat exchanger intermetal fitting 5 will be explained.

As shown in FIG. 1, inside the heating container (Q shown in the figure), the underlined portion 1a of the alumina ring 1 has an intermediate bonding ring 2,
Piping fl! The II metal fitting 3 and the pressing jig 6 are arranged in this order.

Further, in the upper end 1b of the alumina ring 1, an intermediate bonding ring 4, a metal fitting 5, and a pressure jig 7 are arranged in this order.

Next, the inside of the heating container is kept in a vacuum state (5×10-'mm
JIg) and keep the inside of the heating container at 10℃.
/min heating rate.

Next, after holding at 600℃ for 30 minutes, 2℃/m
The temperature was lowered to 580° C. at a temperature lowering rate of 580° C., and while the temperature was lowered for about 30 minutes, the alumina link 1, the intermediate joining ring 2, and the pipe side fittings 35. Nakato mating ring 44-
77 Sad exchange Shinori Kanehaya, 5, apply a pressure force of 0.5 kg/moe 2 with the pressure jig 6.7 to the alumina ring 1, the pipe side fitting 3, and the mature woman exchanger side fitting 5. Pressure brazing. In this pressurizing operation, pressurization is started between the liquidus temperature and the solidus temperature, and the pressure is increased to below the solidus temperature. In addition, the 9th
As shown in the figure, the pressure is 0.05Kg/nm2~2
, 0 Kg/wa', there is no difference in bonding strength.

Next, annealing is performed by holding the temperature at -400°C for 30 minutes.

Further, when the annealing is completed, the temperature is lowered to 150'C by natural cooling, and the pressure brazing operation is completed.

The state of the joints between the alumina ring 1 obtained in this way, the pipe side metal fitting 3, and the heat exchanger side metal fitting 5 is EPMA.
According to the surface analysis, as shown in Fig. 4, the intermediate joint ring 2,
The fine particles of Si are uniformly dispersed over almost the entire area of the intermediate bonding ring 2 (4) and become gradually thinner and more uniformly distributed as they move away from the interface between the intermediate bonding ring 2 (4) and the alumina ring 1.

In addition, near the bonding interface between the intermediate bonding ring 2 (4) and the alumina ring 1, Sl particles are distributed almost entirely in a layered manner, and near-pure A particles are generated near the Si powder particles.
Since lNl is very thin, it is thought that the bonding strength between the alumina ring 1 and the intermediate bonding ring 2.4, the corrosion resistance against Na, and the heat cycle resistance are better than 2E.

Here, when Examples 1 to 3 and Conventional Example 1°2 shown in Table 1 were tested for corrosion resistance against Na, the following results were obtained.

In Fig. 6, the Na immersion time is plotted on the horizontal axis, and in Fig. 8, a load is applied to the alumina ring 1 and the heat exchanger side metal fitting 5 in the directions of arrows P and Q, and 1! when the joint part peels off.
! It is a graph showing the relationship with mechanical strength. In addition, the mechanical strength test was conducted with the intermediate joint ring 4Ill, and the
The size was 0.8+wm, the outer diameter was 49fl, and the inner diameter was 36B. Note that the sodium immersion was performed at 450°C.

As is clear from this graph, as shown in Table 1, Al
In 13I111-3 with high purity, the mechanical strength decreased even when the Na immersion time became long, as shown in Table 1.
Compared to the conventional example 1゜2, which has a low purity, the amount of Al shown in Fig. 1 is smaller, and therefore the corrosion resistance against Na can be improved.

Also, regarding Examples 1 to 3 and Conventional Examples 1.2 shown in Table 1,
i for Na! When fta eating habits were examined by helium leak measurement, the results are shown in Table 2. Here, the amount of helium leak is 1XI Q-"atmc c
/sec or less is considered passing. As is clear from Table 2, when the Na immersion time was 500 hours, the conventional example 1
In the conventional example, 4 8-core cores were rejected, and in the conventional example 2, 10 cores were rejected, but in Examples 1 to 3, there were no rejected products even after 1000 hours, and Examples 1 to 3 were rejected compared to the conventional example. It can be seen that this is better than 1 and 2.

(Leaving space below) Table 2 Next, as shown in Figure 7, we looked at the heat cycle resistance in helium leak measurements when repeated heat cycle operations of raising and lowering between room temperature and 350°C are shown in Table 3. It became so.

(Leaving space below) As is clear from Table 3, Examples 1 to 3 all passed the test, conventional examples 1 and 2 failed as the number of thermal cycles increased, and Examples 1 to 3 passed the test. The heat cycle resistance is #Jfj worse than the conventional example.

By the way, when the mechanical strength of the pipe-side metal fitting 3 and the heat exchanger-side metal fitting 8 was measured by heat treatment, as shown in Table 4, the peel strength test was performed after immersing in Na at 450°C for 500 hours to determine whether or not they were annealed. When conducted, Examples 1 to 3
You can see that it doesn't change much.

In addition, the implementation pAl~ due to the surface roughness of the alumina ring 1
No difference in performance was observed between the three. That is, in the case of Example 1, the peel strength after being immersed in Na at 450° C. for 500 hours was tested, and the results shown in Table 5 were obtained.

Table 5 As is clear from Table 5, the peel strength does not change much between the surface roughness Ra of the alumina ring 1 of 0.1 and 0.8.

In this embodiment, the pressure brazing of a joining structure having a flange structure is described, but the present invention can also be applied to a brazed structure of ceramics and Al of other products and a method of manufacturing the same. '& The ceramics include SIN<, SiC, etc., and the solder material is Al-3.
T-alloys may also be used.

10th [2? As shown in l, α- of alumina ring 1
The purity of Al20m was varied to evaluate Na resistance and temperature increase/decrease durability. As a result, as shown in Table 6, in the thermal cycle test, 500
No leakage was observed even after repeated cycles.

In addition, as shown in Table 7, the results of the Na resistance test showed that α-Al
When the purity of 20m was 75% or more, a little leakage started to occur after 1000 hours, but there was no leakage until 750 hours, and the strength did not decrease as much as W14 when the purity was 75% or more. Furthermore, α-Al2o with a purity of 75% or less
When z was used, the Na resistance deteriorated extremely and the bonding strength also became extremely low, and the results were similar to those in the leak test. Therefore, the overall purity of α-A 120 s is 7.
If it is 5% or more, it can be said that the durability performance is good.

(Margins below) Table 6 [Effects of the invention] As detailed above, this invention provides ceramic parts and A
This has the effect of not only making it possible to firmly connect the two parts to each other through a soldering material, but also improving the corrosion resistance against Na and the like and the durability of the joint between the two parts.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a bonded body of alumina and aluminum having a flange structure according to the present invention, which is pressure-brazed;
Figure 2 is an exploded perspective view of the alumina ring, heat exchanger side metal fittings, piping side metal fittings, intermediate joint ring, etc.; Figure 3 is a graph showing the relationship between time and temperature showing the pressure brazing method;
FIG. 4 is an explanatory view showing the cross-sectional structure of the joint between the alumina ring and the heat exchanger side metal fitting in the present invention, and FIG. 5 is an explanatory view showing the cross-sectional structure of the joint between the conventional ceramic part and the Al part. Figure 6 is a graph showing the relationship between Na immersion time and mechanical strength of the joint, Figure 7 is a graph showing thermal cycles,
FIG. 8 is a cross-sectional view of the joined body after pressure brazing, FIG. 9 is a graph showing the relationship between pressing force and breaking strength, and FIG. 10 is a graph showing the relationship between alumina purity and strength. 1... Alumina ring as a ceramic component, 2
... Intermediate joining ring as a brazing material, 3... Piping side fitting as an Al part, 4... Intermediate joining ring as a brazing material, 5... Heat exchanger side fitting as an Al part, 6 ．．
7... Pressure jig.

Claims (1)

[Claims] 1. In a ceramic component in which an Al component is bonded using a brazing material in which Si is added to Al, the above-mentioned A
1. A brazed structure of ceramics and Al, characterized in that the Al purity of the parts is 98.0% by weight or more. 2. The ceramic and Al brazed structure according to claim 1, wherein the brazing material is an Al-Si alloy. 3. The brazing material is mainly made of Al and contains 6-13% by weight of Si.
, A containing 3% by weight or less of Mg, and other unavoidable impurities.
The ceramic and Al soldered structure according to claim 1, which is an l-Si-Mg alloy. 4. The ceramic and Al brazed assembly according to claim 1, wherein the ceramic component is alumina of 75% by weight or more. 5. Pressure brazing is performed between ceramic parts and Al parts with an Al purity of 98.0% by weight or more by interposing brazing in which Si is added to Al. A brazed structure of ceramics and Al, characterized in that fine particles of Si are precipitated at the bonding interface, and the Si is uniformly diffused in the brazed and joint parts with the Al parts, and becomes thinner toward the Al parts. Production method.