JP2018135220A - Silicon carbide ceramic joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large and long size silicon carbide ceramic joined body that can be used at a high temperature of over 1000°C.SOLUTION: The silicon carbide ceramic joined body formed by joining a plurality of base materials including a silicon carbide ceramic base material, with the plurality of base materials each being a ceramic base material comprising silicon carbide, or being a ceramic base material comprising silicon carbide and a metallic base material, employs silicon as a joining material, with the thickness a of the joint part of the base material and the width b of the joining material satisfying the following formula: 0.1≤b/a≤0.5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bonded body of silicon carbide ceramic material.

  As an example of a ceramic bonding method that has sufficient bonding strength and does not interfere with the semiconductor manufacturing process without impairing the original physical properties of the ceramic to be bonded in a short time treatment, The Si powder or Si thin film is interposed in the joint between the ceramic materials containing free Si, and the joint is locally heated by irradiating the joint with laser light. A technique is described in which Si present in the vicinity of the part is melted and fluidized to fill the joint, and the joint is obtained by mutual movement of Si.

Japanese Patent Laid-Open No. 7-187836

  Silicon carbide ceramics are excellent in heat resistance, corrosion resistance and the like and have very high strength. For this reason, it is applied to high temperature structural members and wear resistant members. Further, in recent years, application to members requiring high reliability such as semiconductors and nuclear power has been studied.

  Ceramic members such as silicon carbide are generally manufactured by a powder sintering method. However, it is technically and costly to manufacture large-sized members, long members, and complex-shaped members by a powder sintering method. The hurdle is high. For this reason, it has been studied to produce a simple-shaped product and to apply it to a large member, a long member, a complicated-shaped member, etc. by joining them.

  As a bonding method of the silicon carbide ceramic material, a solid phase bonding method using a hot press, brazing bonding using an active metal such as copper or titanium as a bonding material, and the like have been reported.

  In the case of a solid phase bonding method using a hot press, bonding is performed while pressing at a high temperature, so that the shape and size of the ceramic material that can be bonded are limited. On the other hand, in the case of brazing joining using an active metal as a joining material, it is possible to join at a relatively low temperature of about 800 ° C. by using a joining material having excellent wettability. Widely used as a method. However, in this case, since the heat resistance temperature of the member is determined by the heat resistance temperature of the active metal bonding material having a low melting point, there arises a problem that the high heat resistance (2000 ° C. or higher) of silicon carbide ceramics is not exhibited.

  In addition, when a large member or a long member is produced by joining, when joining using a heating furnace, a large heating furnace is required to insert the member. Has its limits.

  For the above reasons, when a large, long member intended to be applied at a high temperature of 1000 ° C. or higher is produced by a joining method, only the application of a high melting point joining material and the part to be joined are locally applied. It is desired to join by heating.

  As an example of such a technique, there is a technique as described in Patent Document 1 described above. However, in this method, the ceramic base material needs to contain free Si, and applicable ceramics are limited. In general, ceramics containing free Si are known to have a lower heat-resistant temperature compared to ceramics containing no free Si, and for bonded bodies intended for use at high temperatures exceeding 1000 ° C. Is disadvantageous.

  Furthermore, in the method described in Patent Document 1, it is clarified by examinations by the present inventors that there is room for improvement, for example, the heating method using a laser is not a heating method considering large and long members. It was.

  The present invention provides a large and long silicon carbide ceramic joined body that can be used at a high temperature exceeding 1000 ° C.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present invention includes a plurality of means for solving the above-described problems. For example, a silicon carbide ceramic joined body formed by joining a plurality of base materials including a silicon carbide ceramic base material. The plurality of base materials are ceramic base materials containing silicon carbide, or a ceramic base material containing silicon carbide and a metal base material, and a bonding material for joining the plurality of base materials is silicon, The relationship of 0.1 ≦ b / a ≦ 0.5 is established when the thickness of the bonding portion of the base material is a and the width of the bonding material is b.

  According to the present invention, a bonded body of silicon carbide ceramics obtained by locally heating and joining a large, long member intended to be applied at a high temperature exceeding 1000 ° C. is obtained.

It is the schematic diagram which showed the relationship between the thickness of the base material in the embodiment of this invention, and the width | variety of a joining material. It is a schematic diagram of another example of the relationship between the thickness of the base material and the width of the bonding material in the embodiment of the present invention. It is a schematic diagram of the junction structure in the embodiment of the present invention. It is a schematic diagram of the laser irradiation method in the embodiment of the present invention. It is a graph which shows the result of the bending strength test in Example 1-5 and Comparative Example 1-5 of this invention. It is a figure which shows the mode of the external appearance of the silicon carbide ceramic joined body in Example 2 of this invention.

  An embodiment of the silicon carbide ceramic joined body of the present invention will be described with reference to FIGS. 1 to 6.

  The inventors have a very high heat resistance with a decomposition temperature of 2700 ° C. or higher, and silicon carbide ceramics having characteristics such as high corrosion resistance and high rigidity, using a bonding technique by local heating using a laser, and reducing the temperature to 1000 ° C. We investigated the development of large and long members that can be used in high temperature environments. As a result, the following invention has been achieved.

  Specifically, the silicon carbide ceramic joined body of the present invention is obtained by interposing a joining material between base materials of silicon carbide ceramics to be joined. In the silicon carbide ceramic joined body of the present invention, silicon is used as a joining material.

  As a bonding material to be used, it is preferable to use a bonding material that does not form a mechanically and thermally fragile reaction phase with silicon carbide from the viewpoint of reactivity with silicon carbide. Further, assuming use at a high temperature of 1000 ° C. or higher, the melting point of the bonding material is preferably 1200 ° C. or higher. Furthermore, the silicon carbide ceramic joined body of the present invention is preferably related to a joined body of a large and long member, and it is desirable that the silicon carbide ceramic joined body is locally heated to 1200 ° C. or higher in order to obtain the silicon carbide ceramic joined body. It is. Therefore, the bonding material is required to have a thermal expansion coefficient close to that of the base material.

From the above viewpoint, the silicon carbide ceramic joined body of the present invention is characterized in that silicon is used as the joining material. Silicon does not form a reaction layer with the silicon carbide ceramics of the base material, and its melting point is as high as 1414 ° C. For this reason, the silicon carbide ceramic joined body using silicon as the joining material can be used even at a high temperature of 1200 ° C. or higher. Also, the thermal expansion coefficient of silicon carbide ceramics is 3.1 × 10 ⁻⁶ / K, whereas the thermal expansion coefficient of silicon is relatively close to 3.3 × 10 ⁻⁶ / K. The advantage that the residual stress generated by the temperature change at the time of joining is also reduced is expected.

  FIG. 1 is a schematic diagram showing the range of the thickness of the base material and the width of the bonding material of the silicon carbide ceramic of the present invention. In the silicon carbide ceramic joined body of the present invention, in addition to using silicon for the joining material 120, when the thickness of the joining portion of the substrate 110 is a and the width of the joining material 120 is b, 0.1 ≦ The relationship of b / a ≦ 0.5 is established.

  As described above, the manufacture of a joined body using a heating furnace has limitations in increasing the size and length of the member due to restrictions on the heating furnace. For this reason, as mentioned above, joining by local heating is suitable for obtaining a large and long joined body. Here, it is preferable to locally heat a bonding portion between silicon carbide ceramic base materials 110 sandwiching silicon as bonding material 120 using a laser. Here, in the case where the bonding portion is locally heated using, for example, a laser, when the thickness of the bonding portion of the base material 110 is a and the width of the bonding material 120 is b, b / a is smaller than 0.1. Regarding the conditions, it became clear that a part or all of silicon as the bonding material 120 evaporates and a sufficient bonded body cannot be obtained. This is due to the following reasons.

  When laser light is irradiated to the joint portion of the silicon carbide ceramic joined body, (1) the specific heat of silicon carbide ceramics is significantly smaller than that of silicon (silicon carbide ceramics: 0.2 J / K · g, Silicon: 0.73 J / K · g), (2) silicon carbide ceramics have a higher absorption rate of laser light, etc., so that the silicon carbide ceramic base material around the bonding material is larger than the bonding material silicon. The temperature will be significantly higher. Therefore, under the condition that b / a is smaller than 0.1, the temperature of the silicon carbide ceramics in the peripheral portion is significantly higher than the melting point of silicon before the entire amount of silicon as the bonding material is heated to the melting point. It is presumed that a part or all of silicon has disappeared and bonding failure has occurred.

  On the other hand, even when the laser output is adjusted so that the bonding material does not evaporate, the bonding material melts on the back side of the laser irradiation surface due to heat conduction and heat dissipation to the non-heated part due to local heating. The remainder was confirmed, and the conditions under which the bonding material could be completely dissolved could not be found.

  Next, when the thickness of the bonded portion of the base material is a and the width of the bonding material is b, the strength of the silicon carbide ceramic bonded body is reduced when b / a exceeds 0.5. As a result, it was uneasy to use as a conjugate. This has not yet been shown for a clear reason, but generally for bonding using a bonding material, the narrower the bonding material, the stronger the strength, and the Young's modulus of silicon is silicon carbide. It is presumed that small points (silicon carbide ceramics: 430 Gpa, silicon: 160 GPa) and the like have an influence as compared with ceramics.

  In addition, the thickness a of the joint portion of the base material 110 in the present invention means the short direction of the surface of the base material 110 that contacts the joint material 120. In addition, the width b of the bonding material 120 means the interval between the bonding surfaces of the base material 110.

  In addition, the thickness of the bonding material 120 is desirably the same as the thickness a of the bonding portion of the base 110, but is not limited thereto.

  In addition, the silicon carbide ceramic base material used as the base material 110 of the present invention includes ceramics mainly composed of silicon carbide, composite ceramics composed of a mother phase mainly composed of silicon carbide, and silicon carbide as the main component. And composite ceramics in which the fibers are combined. Further, examples of the metal substrate used as the substrate 110 include, but are not limited to, a zirconium alloy or a composite material of a zirconium alloy and silicon carbide.

  Ceramics containing silicon carbide as a main component are generally produced by a reaction sintering method, a normal pressure sintering method, a hot press method, or the like. Among these, the hot press method needs to be pressurized at the time of sintering, and thus is not very suitable for producing a member having a complicated shape. In the case of the reactive sintering method, sintering can be performed at a relatively low temperature of about 1600 ° C., and dimensional changes during sintering can be suppressed. However, the sintered body contains free Si and pores and is inferior in mechanical properties as compared with the other two methods. In the case of a normal pressure sintered body, although depending on the type of sintering aid, the sintering temperature is as high as about 2000 ° C. and further changes in dimensions during sintering. It is necessary to consider dimensional changes. The method for producing ceramics mainly composed of silicon carbide and the sintering aid can be appropriately selected depending on the shape of the member to be applied and the environmental conditions to be applied.

  As a fiber mainly composed of silicon carbide, a fiber produced by depositing silicon carbide on a carbon core wire by chemical vapor deposition (CVD), or an organic silicon polymer such as polycarbosilane as a precursor, spinning, inorganic Fiber (Nicalon (registered trademark)) obtained by crystallization, and fiber containing titanium or zirconium obtained by adding titanium alkoxide or zirconium alkoxide to an organosilicon polymer such as polycarbosilane and making it mineral (Tyranno fiber (registered) Trademark)), fibers obtained by adding aluminum alkoxide to an organosilicon polymer such as polycarbosilane, and spinning and mineralizing (SA fibers (manufactured by Ube Industries, Ltd.)). Of these, the use limit temperature of Tyranno fiber containing titanium is 1300 ° C, and the use limit temperature of Tyranno fiber containing zirconium is 1500 ° C, indicating high heat resistance. Preferred for use of the present invention for application purposes. Nicalon has been reported to take up oxygen in the infusibilization stage during production and cause a decrease in strength at 1300 ° C. or higher. Therefore, it is more preferable to use a silicon carbide fiber (Hinicalon (registered trademark)) that has been infusibilized by an electron beam irradiation method or the like, and has improved heat resistance by reducing the amount of oxygen. When comparing room temperature strength after heat treatment in Ar gas, Nicalon, hynicalon, Tyranno fiber, etc. show a decrease in strength by heat treatment at 1000 ° C. or higher, while SA fiber has strength even at 2000 ° C. It is more preferable because it does not show a decrease.

  As a method for producing a silicon carbide composite material in which silicon carbide fibers are combined, a chemical vapor immersion method (CVI method) in which a CVD gas is allowed to flow in the voids of a silicon carbide fiber preform to deposit a silicon carbide matrix on the fiber surface, A polymer impregnation firing (PIP method) method in which silicon carbide fiber fabric is densified and sintered repeatedly in a mixture of organosilicon polymer and silicon carbide powder, and silicon carbide nanoparticles and organosilicon compounds are slurried in silicon carbide fibers A nano-infiltration transition eutectic phase process method (NITE method) in which coating and firing are performed has been reported. Among these, the CVI method, the NITE method, and the like are preferable because a circular tube shape, a rod-shaped large member, a long member, and the like can be manufactured.

  Examples of the shape of the substrate include, but are not limited to, a plate material, a square material, a disk, a cylindrical tube, and a round bar. Examples of the joining structure include a lap joint, a butt joint, and a fillet joint, but are not limited thereto. The shape and joining structure of these base materials can be appropriately selected according to the application and shape of the member to be applied.

  Furthermore, the direction of the base materials to be joined is not limited to the direction as shown in FIG. 1, but may be the direction as shown in FIG. 2, for example, or may be in another direction. FIG. 2 is a schematic view showing another example of the range of the thickness of the base material and the width of the bonding material of the silicon carbide ceramic of the present invention.

Examples of the laser used for local heating suitably used for bonding include CO ₂ laser, YAG laser, excimer laser, fiber laser, disk laser, semiconductor laser, picosecond laser, nanosecond laser, femtosecond laser, and the like. As the wavelength, laser light having wavelengths in the far infrared, visible, and ultraviolet regions can be used. These can be appropriately selected according to the material to be applied and the material and shape of the bonding material.

  As the beam shape of the laser beam, a circular beam, an elliptical beam, a linear beam, or the like can be used. As for the beam shape, an optimum shape can be selected according to the shape and size of the joint.

  Hereinafter, specific examples will be described.

<Example 1>
FIG. 3 shows a schematic diagram of the joining structure. A butt joint structure was studied as a joint structure. As the substrate 110, silicon carbide ceramics (model SCP01) manufactured by Nippon Fine Ceramics Co., Ltd. was used. The size of the test piece was 10 mm × 20 mm × thickness a = 2 mm, and the two test pieces were joined together as shown in FIG.

  The bonding material 120 was pre-sprayed with silicon having a width of 0.2 mm on one of the bonded portions of the two test pieces using an atmospheric plasma spraying method (the width of the bonding material b = 0.0). 2 mm, b / a = 0.1) was used.

  The butt joint material shown in FIG. 3 was joined by laser. The laser oscillator used was a fiber laser oscillator (model YLR-2000, maximum output 2 kW, wavelength 1070 nm) manufactured by IPG Photonics. A sample was placed in a vacuum chamber, the atmosphere in the chamber was reduced to 10 Pa or less, and then irradiated with a laser.

  FIG. 4 shows a schematic diagram of laser irradiation. The laser beam 320 was irradiated to the joint part 310 of the butt joint material shown in FIG. The shape of the laser beam 320 was linear (10 mm × 0.5 mm).

<Example 2>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, is 0.2 mm (the bonding material width b = 0.4 mm, b / a = 0.2). A bonding material was produced under the same conditions as in Example 1.

<Example 3>
The width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, was set to 0.2 mm and 0.4 mm, respectively (bonding material width b = 0.6 mm, b / a = 0.3). A joining material was produced under the same conditions as in Example 1.

<Example 4>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, is set to 0.4 mm (bonding material width b = 0.8 mm, b / a = 0.4). A bonding material was produced under the same conditions as in Example 1.

<Example 5>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, is 0.5 mm (both bonding material width b = 1.0 mm, b / a = 0.5). 1 was prepared under the same conditions as in 1.

<Example 6>
The size of the test piece is 10 mm × 20 mm × thickness a = 1 mm, and the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, is set to 0 mm (no application) and 0.2 mm, respectively. Except for the width b = 0.2 mm and b / a = 0.2), a bonding material was produced under the same conditions as in Example 1.

<Example 7>
The size of the test piece is 10 mm × 20 mm × thickness 1 mm, and the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, is 0.2 mm (the bonding material width b = 0.4 mm). , B / a = 0.4) A bonding material was produced under the same conditions as in Example 1.

<Comparative Example 1>
The width of silicon, which is a bonding material previously applied to the joint portion of the test piece, was set to 0 mm (no application) and 0.05 mm (the bonding material width b = 0.05 mm, b / a = 0.025), respectively. Produced a bonding material under the same conditions as in Example 1.

<Comparative example 2>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, was 0.05 mm (bonding material width b = 0.1 mm, b / a = 0.05). 1 was prepared under the same conditions as in 1.

<Comparative Example 3>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, was 0.6 mm (both bonding material width b = 1.2 mm, b / a = 0.6). 1 was prepared under the same conditions as in 1.

<Comparative Example 4>
Except for the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, was 1.0 mm and 0.5 mm, respectively (bonding material width b = 1.5 mm, b / a = 0.75), A bonding material was produced under the same conditions as in Example 1.

<Comparative Example 5>
Except that the width of silicon, which is a bonding material previously applied to the bonding portion of the test piece, was 1.0 mm (bonding material width b = 2.0 mm, b / a = 1.0). 1 was prepared under the same conditions as in 1.

  Table 1 shows the status of the joining test results when the width of the joining material in each of the above examples and comparative examples was used as a parameter, and 4 of the joined bodies, which were carried out on a sample having a specimen size of 10 mm × 20 mm × thickness 2 mm. A point bending strength test result is shown. Further, FIG. 5 shows the strength test results of the four-point bending. In addition, about the strength of 4 point | piece bending, it was set as the value normalized by setting the intensity | strength of the joined body obtained in Example 2 of the joining material width | variety: 0.4 mm in which the highest intensity | strength was obtained to 1 as 1.

  First, regarding the influence of the bonding material width on the bonding property, when the thickness of the bonding portion of the base material is a and the width of the bonding material is b, b / a is smaller than 0.1 (Comparative Example 1). For 2), it cannot be joined due to the loss of the joining material, or it is barely joined, but the joining part is easily cracked due to the decrease in joining material, and a sound joined body cannot be obtained. It was.

  On the other hand, when the thickness of the bonding portion of the base material is a and the width of the bonding material is b, b / a is 0.1 or more (Example 1-7, Comparative Example 3-5). In either case, there was no problem in appearance, and it was possible to obtain a joined body having a good joined state. As an example of the joined body, a photograph of the joined body of Example 2 in which the width of the joining material is 0.4 mm is shown in FIG.

  Next, the test result of four-point bending will be described. As shown in Table 1 and FIG. 5, the condition with the highest bending strength among the conditions that were successfully joined this time was the joined body of Example 2 in which the width of the joining material was 0.4 mm. In addition, when the thickness of the bonding portion of the base material is a and the width of the bonding material is b, the condition within the range of the present invention is 0.1 ≦ b / a ≦ 0.5 (Example 1-7 ) Showed a high strength of 90% or more with respect to the result of the bonding material width of 0.4 mm.

  On the other hand, regarding the condition where b / a exceeds 0.5 (Comparative Example 3-5), the bending strength was 80% or less with respect to the bonding material width of 0.4 mm, which resulted in a decrease in strength.

  As described above, in a silicon carbide ceramic joined body formed by joining a plurality of base materials including a silicon carbide ceramic base material, the plurality of base materials include ceramic base materials containing silicon carbide or silicon carbide. A ceramic base material and a metal base material, and silicon is used for the bonding material, and when the thickness of the bonding portion of the base material is a and the width of the bonding material is b, 0.1 ≦ b / a ≦ 0 When the relationship of .5 is established, it is possible to provide a large and long silicon carbide ceramic joined body that can be used at a high temperature exceeding 1000 ° C.

  Moreover, since the silicon carbide ceramic base material 110 is a silicon carbide composite material reinforced with fibers containing silicon carbide as a main component, it has excellent properties at high temperatures, and can be used at high temperatures exceeding 1000 ° C. A joined body more suitable as a large and long silicon carbide ceramic joined body is obtained.

  Furthermore, since the silicon carbide ceramic joined body is joined by local heating with the laser beam 320, it is easy to heat only the joining material and its surroundings to a temperature necessary for joining, and a good joined state. Is obtained.

  In addition, silicon carbide ceramic base material 110 before bonding constituting the silicon carbide ceramic bonded body has silicon as bonding material 120 in advance in a range of 1/10 to 1/2 of the thickness of silicon carbide ceramic base material 110. By being provided, the bonding state between the bonding material 120 and the base material 110 can be improved.

  Furthermore, since silicon is applied to the silicon carbide ceramic substrate 110 by the atmospheric plasma spraying method, silicon, which is a high melting point material, can be applied in advance as the bonding material 120, and a better bonding state can be obtained. Can be obtained.

  The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to those having all the configurations described, and can be appropriately combined and improved without departing from the scope of the invention. It is.

110 ... base material,
120 ... bonding material,
310 ... Junction part,
320 ... Laser beam,
a: the thickness of the joint portion of the substrate,
b: The width of the bonding material.

Claims (5)

A silicon carbide ceramic joined body formed by joining a plurality of base materials including a silicon carbide ceramic base material,
The plurality of base materials are ceramic base materials containing silicon carbide, or a ceramic base material containing silicon carbide and a metal base material,
The bonding material for bonding the plurality of base materials is silicon,
The relationship of 0.1 ≦ b / a ≦ 0.5 is established when the thickness of the bonding portion of the plurality of base materials is a and the width of the bonding material is b. Joined body. In the silicon carbide ceramic joined body according to claim 1,
The silicon carbide ceramic base material is a silicon carbide composite material reinforced with fibers mainly composed of silicon carbide. In the silicon carbide ceramic joined body according to claim 1,
The silicon carbide ceramic joined body is joined by local heating with a laser. In the silicon carbide ceramic joined body according to claim 1,
The silicon carbide ceramic base material before bonding constituting the silicon carbide ceramic bonded body is preliminarily provided with silicon as the bonding material in a range of 1/10 to 1/2 of the thickness of the silicon carbide ceramic base material. A silicon carbide ceramic joined body characterized by comprising: In the silicon carbide ceramic joined body according to claim 4,
The silicon carbide ceramic joined body, wherein the silicon is applied to the silicon carbide ceramic substrate by an atmospheric plasma spraying method.

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