JPH03218987A - Production of silicon carbide/metal composite pipe - Google Patents

Abstract

PURPOSE:To enhance denseness, high toughness and impact resistance by laminating a layer formed of the mixed powder of SiO and C, an Si layer contg. Ti and the layer of the powdery mixture of Al and Fe3O4 and allowing these layers to react by the centrifugal force and sintering the layers. CONSTITUTION:A tubular material is obtained by forming a powdery molded body layer consisting of the uniform mixture of SiC powder and C powder on the inner face of a metallic pipe 1 and annularly arranging a mixture described hereunder on the surface thereof and laminating the layer of the powdery mixture of Al and Fe3O4 to the inside thereof. The mixture is obtained by adding 0.4-4.0 pts.wt. Ti to 100 pts.wt. Si excess for Si amount necessary to change C contained in the above-mentioned molded body layer into SiC. Then this tubular material is rotated by a centrifugal machine and thermit reaction is caused in the innermost layer by the sufficient centrifugal force. SiC is allowed to react and sintered by the heat of reaction. An Fe-Si alloy layer 2, an SiC layer 3, a metallic Si-Fe layer 4 and an Al2O3 layer 5 are formed on the inner face of the metallic pipe 1.

Description

[Detailed description of the invention] This industrial field of application] The present invention relates to a method for manufacturing a double tube made of silicon carbide and metal. It is applied to combustion pipes of gas turbine engines, hot air flow transport pipes, wear-resistant cylinder liners, etc.

The centrifugal thermite method is a method for joining ceramics to metal tubes. This is a method in which the inner surface of a metal tube is coated with aluminum powder and iron oxide powder, and then the metal and the reaction product ^120 layer are bonded through iron produced by the thermite method.

Although this centrifugal thermite method provides a composite tube with a relatively strong bond between metal and ceramics, it is still insufficient as a high-strength composite tube. Therefore, the present inventor first disclosed a method in which a silicon carbide layer is interposed between the metal tube and the 81203 layer using the thermite method, and these layers are bonded using metal silicon, iron, or a silicon-iron alloy. (Unexamined Japanese Patent Publication No. 58-95
Publication No. 675).

[Second invention or issue M to be solved] By the method described above, a double-gauge tube that is dense, strong, and has good thermal shock resistance was obtained. This caused the problem of peeling under certain conditions.

This is because ^l203 has a larger coefficient of thermal expansion than the underlying SiC.

Therefore, the present invention aims to improve the method disclosed by the present inventors and to prevent the 81203 layer from peeling off even under thermal cycles.

[Means to solve the problem]

The present invention achieves the above object by layering a powder compact layer made of a uniform mixture of silicon carbide powder and carbon powder on the inner surface of a metal tube, and coating carbon in the powder compact layer on the surface of the powder compact layer. A tubular material in which excess silicon is arranged in an annular shape relative to the amount of silicon required to convert it into silicon carbide, and a powder layer of a mixture of aluminum and triiron tetroxide is layered on the innermost layer is rotated in a centrifuge under sufficient centrifugal force. When a thermite reaction is caused in the innermost layer, and the reaction heat is used to produce silicon carbide.
Charcoal 1 characterized by being added within the range of ', 4.0
The amount of titanium added to 6 silicon achieved by the manufacturing method of metal double tubes is in the range of 0.4 to 4.0 per 100 silicon by weight, as shown in the examples below. It is effective, and the range of 1.0 to 2.5 is preferable.

[For production]

Titanium generates a concentrated distribution layer on the surface of the ^1 20 , , -' S i C layer, and Aft. Good wetting from layer to SiC layer strengthens the bond of the AN,0, layer to the SiC layer.

〔Example〕

Husband L carp 1 Inner diameter 80 ml as outer layer metal pipe, pipe length 12
0 16 rn, wall thickness 4111111 iron <FC30
) using a commercially available a-SiC powder (Fujimi Abrasive Industry Co., Ltd.) GC grade, #2000: #4000: #80
A homogeneous mixture of carbon black (Mitsubishi Chemical Industries, Ltd. Diablack I) with a weight ratio of 1:0.8 (187ε) was applied to the inner wall of the iron pipe so that the bulk density was 184ε CTn3. uniform thickness
It was layered to a thickness of approximately 6 m (IL). The layering was carried out by inserting a core (of an appropriate diameter) into a metal tube and filling the space between the metal tube and the core with the mixture.9 Next, titanium powder was similarly applied onto this mixture layer. Silicon powder containing (
The amount of titanium added is shown in FIG. The main component, silicon, has a purity of 99.9%, and various particle sizes are blended to improve filling properties. Further, 213 g (1.1 times the theoretical amount) of titanium (using sponge titanium fine powder) was filled to a substantially uniform thickness of about 5+ ms.

Furthermore, for internal measurement, aluminum powder (purity 78%, approximately 200 mesh) and FeJ powder (reagent special grade, approximately 200 mesh) were used.
77 g of a homogeneous mixture having a molar ratio of 823 was uniformly layered to a thickness of about 3 IIl.

The test piece prepared as described above was inserted and fixed into the center of the mold of a cantilever horizontal centrifuge used for centrifugal casting experiments. The mold is designed not only for fixing, but also for cooling. The test piece attached to the rotating part of the centrifuge was rotated without eccentricity, and when it reached approximately 200G, aluminum and FesO. The mixture was ignited to cause a lumisoto reaction. The reaction sintering of silicon carbide induced by the heat generated by the Terumi-Sohe reaction was also an exothermic reaction, so all the reactions were completed instantly.

After cooling, the rotation was stopped and the specimen taken out from the mold had a silicon carbide ceramic layer formed on the inner layer with a thickness of about 6WIII, and the surface had a thickness of about 0.4W+w+^12.
0.It was covered in layers. FIG. 1 schematically shows this cross section. In the figure, 1 is a cast iron pipe, 3 is a SiC layer, and 5 is 8 l20
There are many layers.

Next, the cross section of the Nikuno test piece was mirror polished and analyzed using an electron probe microanalyzer (EPM^).

The innermost layer 5 has a thickness of about 0.4 mm.
, 0:1 layer 5 and silicon carbide layer 3, although there seemed to be some chemical bonding, mainly Si--Fe1 gold layer 4 was present. Although it was a small amount, a concentrated distribution of titanium was detected between layer 5 and silicon carbide layer 3Q, and this was found in Af.
0,' It was thought that the bonding force between silicon carbide was further enhanced in the microscopic region.

In the silicon carbide layer 3, tL metal-resistant silicon containing a small amount of iron was distributed in a net shape in an amount of about 15°J. Iron-rich Fe-Si alloy layer 2 continuous with free metallic silicon inside
was present, causing diffusion bonding. In addition, since this reaction took place instantaneously, there was no trace of the combustion reaction of carbon in the composition, even in the air, and no air bubbles were observed.3 U Takumi 1 Using the same method as in Example 1. A composite tube was similarly manufactured using only silicon powder without titanium.

L1 carp Composite tubes with a tube length of 120 mm manufactured in Comparative Example 1 and Example 1 were each cut into tube lengths of 45+ nm to prepare thermal shock test pieces. This test evaluates peeling damage of the ^1203 layer.

Place the above test piece on an elevator type pedestal with a heating chamber on the upper side of a vertical electric furnace and an Ar gas blowing cooling chamber on the lower side,
It was exposed to rapid heating and cooling from about 850° C. to about 120° C. with heating for 1 minute and cooling for 1 minute and 30 seconds. During cooling, a shield plate is automatically inserted between the heating and cooling chambers to separate them.

The relationship between the number of repetitions of cycle automatic operation during the test and the occurrence of layer peeling is summarized in Figure 2 as a result.

〔Effect of the invention〕

According to the present invention, the inner side of the metal tube is
203 layers are formed, and the metal tube, the SiC layer, and the Si
C layer and 80. 0. In a silicon carbide metal composite tube in which layers are bonded with metal silicon, iron, or SFe gold, the heat of the 81203 layer is generated by generating a concentrated layer of titanium at the interface between the innermost 8120 layer and the SiC layer. Peeling due to cycles can be prevented.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a silicon carbide/metal composite tube, and FIG. 2 is a diagram showing the results of a thermal cycle durability test of the composite tube. 1- Cast iron pipe, 2... Fe-Si base metal layer, 3
...SiC layer, 4...Metal Si, 'Si Fe metal continuous layer, 5--
・^f, 04th layer.

Claims (1)

[Claims] 1. A powder compact layer made of a uniform mixture of silicon carbide powder and carbon powder is layered on the inner surface of a metal tube, and the amount of silicon required to convert carbon in the powder compact layer to silicon carbide is deposited on the surface of the powder compact layer. A tubular material in which excess silicon is arranged in a ring shape, and a powder layer of a mixture of aluminum and triiron tetroxide is layered on the innermost layer is rotated in a centrifuge to cause a thermite reaction in the innermost layer under sufficient centrifugal force. When performing reaction sintering of silicon carbide using the reaction heat, 1 silicon by weight is added to the silicon layer.
A method for manufacturing a silicon carbide/metal composite tube, characterized in that titanium is added in a range of 0.4 to 4.0.