JP2804766B2 - Joint of ceramic and metal - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a joined body of ceramic and metal having high joining strength, particularly high-temperature joining strength.

[Prior Art] Conventionally, a so-called active metal method has been adopted as one of the methods for joining with a ceramic metal. In this active metal method, a brazing material is interposed between a ceramic and a metal, and is heated and melted to join the ceramic metal. As this brazing material, an alloy containing an active metal, such as an Ag-Cu-Ti ternary system, is used.

Such a brazing material is widely used because it can be joined in a relatively low temperature range (800 to 900 ° C.), the performance of the joined body is reliable, and the joining operation is simple.

In other active metal methods, Cu-Ti, Ni-Ti and the like, Ti
There have been reported many examples of joining using an intermediate material combining a metal element having a eutectic with a low melting point.
No. 16, JP-A-61-127674).

[Problems to be Solved by the Invention] Such a brazing material usually exhibits a certain bonding strength, but the Ag-Cu-Ti-based brazing material has a eutectic point of Ag-Cu.
Since it is as low as 780 ° C, it has a drawback that it lacks high-temperature strength.

[Purpose] An object of the present invention is to improve the bonding alloy used in the active metal method, which is easy to work, to realize a highly reliable bonding between ceramics and metal even at high temperatures. .

[Means and Actions for Solving the Problems] The gist of the first invention for solving the above problems is that, when the ceramics and the metal Ni are joined, the ceramics are inserted between the ceramics and the metal Ni. In a joined body in which a bonding reaction layer is formed on the metal side and a filler layer is formed on the metal Ni side, the filler layer is made up of 15% by weight or less of Ti and 10 to 50% by weight.
Cu, and Ni, and the filler layer, Ni
A joined body of a ceramic and a metal, wherein at least one of Cu solid solution, NiTi solid solution, CuTi solid solution, and NiCuTi solid solution is present.

Further, the gist of the second invention is the joined body of ceramics and metal according to claim 1, wherein another metal is joined via metal Ni as a joined body.

(1) First Invention In the active metal method, as shown in FIG. 1, a ceramic 1 and a metal Ni3 are interposed between a ceramic 1 and a metal Ni3.
Is formed, and a metal filler layer 7 is formed adjacent thereto.

The bonding reaction layer 5 varies depending on the composition of the ceramics 1, but includes, for example, TiN, TiO, Ti ₂ O, TiC, TiSi, and the like as components.
In some cases, the composition further includes metal Ti.
TiN is formed when the ceramic has N, and TiO, TiO
₂ is produced when the ceramic has O, TiC is produced when the ceramic has C, and TiSi is produced when the ceramic has Si.
Generated when This thickness is usually several μm or less.

The filler layer 7 is a metal layer formed at the same time as the formation of the bonding reaction layer 5 and containing Ti, Cu, and Ni. The composition of the filler layer 7 is not always uniform, and varies depending on its position. In particular, it is often non-uniform because a large amount of Ti is present or a solid solution or eutectic having a special composition is formed. Unless otherwise specified, the composition of the filler layer 7 described below is an average value of the entire layer.

In the joined body of the present invention, in particular, the metals contained in the filler layer 7 are solid solutions, that is, a solid solution of NiCu, a solid solution of NiTi (a solid solution of Ti in Ni), and a solid solution of CuTi (solid solution of Ti in Cu). ), NiCuTi solid solution (a solid solution of Ti in a NiCu solid solution), by controlling the amount of Ti and Cu, through the bonding reaction layer 5 to the ceramics 1 even at high temperature. A composition that strongly binds is selected.

The content of Ti in the filler layer 7 needs to be 15% by weight or less. 15% by weight is the upper limit at which Ti forms a solid solution in a solid solution of Ni or Ni-Cu.
It is formed of a Ni-intermetallic compound or the reaction between the ceramics 1 and the filler layer 7 progresses, leading to a decrease in bonding strength.

Cu is added in order to increase the fluidity of the filler layer 7 and to promote the reactivity with the ceramics 1, and it is necessary that Cu be 10% by weight or more. The reason for setting the upper limit to 50% by weight is that if the amount of Cu in the filler layer 7 is large, sufficient bonding strength cannot be obtained. Further, in the high-temperature oxidation of the Cu-Ni alloy, the oxidation resistance is improved as the Ni content is larger, and therefore, it is preferable that the Cu content is small in view of the oxidation resistance.

As a method of forming the joined body of the present invention, a Ti, Cu foil and, if necessary, a Ni foil are interposed between ceramics and Ni for heat joining, or a Ti, Cu powder and In this case, the paste is formed by forming a Ni powder into a paste with an organic binder or a solvent, interposing the paste between the ceramic and the Ni, and performing heat bonding. Of course, a paste and a foil may be used in combination. Alternatively, the metal foil or the metal powder itself may be an alloy formed in advance by adding Ti, Cu and, if necessary, Ni.

The content of each metal can be adjusted by adjusting the thickness of each metal foil, the composition of the paste, or the composition of the foil or powder alloy. In addition, by adjusting the conditions of the heat treatment at the time of joining, for example, the heating temperature and time, Cu, T
The content can also be adjusted by the degree of diffusion between i and Ni.

As the heating atmosphere conditions at the time of joining, since the reaction between Ti and ceramics 1 is an important factor for obtaining good joining strength, an atmosphere from which O, N, C, and the like, to which Ti easily reacts, is preferably removed. Good in the middle and in the Ar air current.

The heating temperature is preferably from 1000 ° C. to 1250 ° C., particularly preferably from 1200 ° C. to 1250 ° C. in order to adjust the filler layer 7 to a desired composition and improve the bonding strength. In order to promote the composition of the NiCuTi solid solution, increase the Ni concentration of the filler layer 7 and improve the heat resistance, the heat bonding time may be lengthened, or heat treatment may be performed at a temperature lower than the heat bonding temperature for a long time after the heat bonding. .

In the Ni-Cu-Ti system of the present invention, Cu-Ti
Melting point of low melting point (Cu-CuTi eutectic melting point is below 900 ℃)
Reacts moderately with ceramics, and the extra unreacted Ti and Cu form a solid solution with Ni during heating, resulting in a highly heat-resistant and reliable bonded body.

In addition, applicable ceramics include silicon nitride, sialon, alumina, aluminum nitride, and any other ceramics having a melting point higher than the heating temperature at the time of joining (for example, 1000 ° C. to 1250 ° C.).

(2) Second Invention In the second invention, another metal is further joined to Ni of the first invention. Examples of the metal include carbon steel, alloy steel, stainless steel, heat-resistant steel, maraging steel, iron-based low expansion metals (such as Kovar, Incoloy 903, 42 alloy, Invar, and Super Invar), tungsten, molybdenum, and cermet. Applicable to various metals.

Various methods are possible for joining this metal and Ni,
For example, when joining Ni and ceramics in the first invention, the joining may be performed simultaneously by interposing a foil or paste such as Ti or W between the metal and Ni.
In addition, the metal and Ni may be joined in advance by, for example, friction welding, electron beam welding, diffusion joining, or the like, and then joined as in the first invention, and conversely, after joined as in the first invention. Alternatively, the metal and Ni may be joined. In the second invention, it can be seen that Ni is interposed in order to bond another metal to the ceramic, and the thickness thereof is such that a part is supplied to the filler layer 7 and the rest is left as the Ni layer. Since the presence of Ni is sufficient, the first surface is formed on the joining surface by placing Ni foil, Ni plating, Ni deposition, and Ni sprayed metal.
The joined body of the invention may be formed.

In each invention, the composition of the formed filler layer 7 is specified by a general method, for example, electron probe microanalyzer (XMA, EPMA), energy dispersive X-ray analysis (ED
X) and the like.

[Effects of the Invention] The joined body of the present invention not only shows a sufficient joining strength at room temperature, but also exhibits a sufficient joining strength because it hardly changes even at a high temperature. As a result, it is possible to realize bonding of ceramics and metal that can be used sufficiently for structures used in high-temperature atmospheres.
It has become possible to utilize ceramics' features (heat resistance, corrosion resistance, wear resistance). For example, a gas turbine engine, a turbocharger rotor, a piston, an intake valve, an exhaust valve, and the like.

Example Next, an example will be described.

Example 1 Materials shown in Table 1 were prepared and set in the positional relationship shown in FIG. That is, a Si ₃ N ₄ sintered body 9 was used as the ceramics 1 to be joined, and a Ti foil 11, a Cu foil 1
3, the Ni plate 15 is superimposed to have the basic configuration shown in FIG. 1, and further, the Ti foil 17, the W plate 19, the Ti foil 21, the Ni plate 23, the Ti foil 25 are superimposed, and finally the stainless steel (Fe26Cr) 27 were stacked.

This was joined by heating at 1100 ° C. to 1250 ° C. in a vacuum of the order of 10 ⁻⁶ Torr.

After the joining, the joint is cylindrically ground to a diameter of 7 mm, and as shown in FIG. 3, the center is a joining reaction layer 5 and a filler layer 7, with an upper span of 10 mm, a lower span of 30 mm, and a load application speed of 0.5 mm /
Under the test conditions of min, a four-point bending test was performed in the atmosphere at room temperature and in a vacuum of the order of 10 ^-3 Torr at 600 ° C., and three pieces of breaking strength were measured. Table 2 shows the results.

In order to adjust the Ti content and the Cu content in the filler layer 7, the thickness and the heating temperature of the Ti foil 11 and the Cu foil 13 were variously changed and joined.

The composition of the filler layer 7 was obtained by cutting the sample at right angles to the joint surface after the strength measurement test, and analyzing five arbitrary portions of the intermediate layer with an X-ray microanalyzer (XMA).

As shown in Table 2, the joined body of the example has a sufficient joining strength both at room temperature and at a high temperature. Ti
If the content exceeds 15% by weight, the joining strength is greatly reduced. Cu content exceeds 50% by weight or 10% by weight
If it is less than, the bonding strength is low and the strength decrease during hot working is large.

Example 2 A material different from Example 1 in that ceramic was changed to Sialon was prepared, and similarly heated and joined to perform a four-point bending test. Table 3 shows the results.

The same results as in Example 1 were obtained for Sialon.

-Example 3 The thickness of the Ni plate 15 was further changed from that of Example 1, and a four-point bending test was performed by heating and joining similarly. Table 4 shows the results. As a comparative example, a Ti-Ag-Cu-based active brazing material was used instead of the Ti foil 11 and the Cu foil 13.

The joined body of this embodiment is superior in hot strength to AgCuTi brazing material. Also, it can be seen that the thickness of the Ni plate affects the bonding strength. In particular, it can be seen that the strength is higher when the Ni plate 15 of 0.5 mm or more is used.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are explanatory views of a joining structure in an embodiment,
FIG. 3 shows a configuration diagram of a four-point bending test. 1 ...... ceramics, 3 ...... metal (Ni) 5 ...... bonding reaction layer, 7 ...... filler layer 9 ...... Si ₃ N ₄ sintered body 11,17,21,25 ...... Ti foil 13 ...... Cu foil , 15,23 ... Ni plate 19 ... W plate 27 ... Stainless steel (Fe26Cr)

Continuing on the front page (72) Inventor Toshio Narita 9-7-8 Shinkotoni 1-chome, Kita-ku, Sapporo-shi, Hokkaido (72) Inventor Katsumi Miyama 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan 72) Inventor Masaya Ito 14-18, Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Inside Japan Pearl Beads Co., Ltd. (56) References JP-A-58-91088 (JP, A) .Cl. ⁶ , DB name) C04B 37/02 B23K 1/00 310

Claims (2)

(57) [Claims] 1. A joined body in which a bonding reaction layer is formed on the ceramic side and a filler layer is formed on the metal Ni side between the ceramic and the metal Ni when the ceramic and the metal Ni are bonded. But less than 15 wt% Ti, 10-50 wt%
While having Cu and Ni, the filler layer includes NiCu
A joined body of ceramic and metal, wherein at least one of a solid solution, a NiTi solid solution, a CuTi solid solution, and a NiCuTi solid solution is present. 2. The joined body of ceramics and metal according to claim 1, wherein another metal is joined via metal Ni as a joined body.