JPH0543663B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a ceramic composite material with excellent strength and fracture toughness, and a method for manufacturing the same. [Prior art] Ceramic fibers and whiskers are dispersed as reinforcing materials in ceramic powder such as Al ₂ O ₃ ,
It is known that ceramic composite materials can be obtained by sintering (FC report,
(See Vol. 4, No. 6, (1986)). However, since such ceramic composite materials use ceramic powder as a matrix raw material, it is difficult to uniformly and densely mix and disperse them with fibers or whiskers. For this reason, mechanical mixing and dispersion has been carried out using a ball mill or the like, but it was inevitable that the fibers and whiskers would be damaged or cut. Further, even when mechanically mixed and dispersed, when the fiber density was increased, the powder could not enter between the fibers, and even when sintered, the powder could not be densified, and sufficient properties could not be obtained. Furthermore, as mentioned above, it is difficult to disperse ceramic fibers or whiskers into ceramic powder, so the ceramic fibers that can be introduced are limited to short fibers or whiskers. However, since short fibers and whiskers have short fiber lengths, the energy dispersion in response to external stress is localized, making it impossible to fully utilize the high strength properties of the introduced fibers, which can significantly improve properties as a composite material. I couldn't help it. [Problems to be Solved by the Invention] In view of the conventional circumstances, the present invention introduces long fibers as reinforcing materials and improves the dispersion of fibers and matrix, thereby achieving excellent strength and breakability. The purpose of the present invention is to provide a ceramic composite material with a high quality. [Means for Solving the Problems] In order to achieve the above object, the present invention uses crystallized glass as a matrix, and contains 30 to 50% by volume of continuous fibers or long fibers of oxide ceramics in the matrix. The present invention provides a ceramic composite material that has been improved. In addition, the production of this ceramic composite material is a method characterized by impregnating continuous fibers or long fibers of ceramic with the base glass of molten crystallized glass, and then crystallizing the base glass composited with the fibers. It is carried out by. Crystallized glass is glass made crystalline by heat treatment, ultraviolet irradiation, etc. Among them, Li ₂ O−SiO ₂ −Al ₂ O ₃ and Na ₂ O−Al ₂ O ₃ have excellent strength and heat resistance.
−SiO ₂ , Na ₂ O−CaO−MgO−SiO ₂ , MgO−
Al ₂ O ₃ −SiO ₂ , PbO−ZnO−B ₂ O ₃ , ZnO−B ₂ O ₃
−SiO ₂ , SiO ₂ −B ₂ O ₃ −Al ₂ O ₃ −MgO−K ₂ O−F
It is preferable to use . Ceramic fibers used as reinforcing materials are oxide-based continuous fibers or long fibers, and these may be used as they are to form a composite, but for example, a preform may be created in advance or a material woven into a cloth may be used. It is also possible. [Function] In the present invention, crystallized glass is used as a matrix, and the original glass is impregnated into continuous fibers or long fibers of oxide ceramics in a heated molten state to form a composite, and then crystallized. Ordinary glass is amorphous and has a low softening point, so it has low heat resistance and bending strength of about 5 to 10 kg/ ^mm2 , but in the present invention, the heat resistance is improved by using crystallized glass. Significantly improved strength from 30 to 60
Improved to about Kg/mm ² . These characteristics of crystallized glass make it suitable for use as a structural material, which is why it is called glass ceramics. In addition, the melting point of the original glass is about 600 to 1300℃,
Ceramics powder sintering temperature (e.g. Al ₂ O ₃
(1400-1700℃), so even if it is impregnated into ceramic continuous fibers or long fibers (the maximum heat resistance temperature is generally 1200-1300℃) in the molten state, it will not deteriorate the ceramic continuous fibers or long fibers. do not have. Note that the crystallization temperature of glass is lower than the melting temperature. The matrix of crystallized glass is obtained by crystallizing the molten original glass and compositing it with ceramic continuous fibers or long fibers, but since there is no shrinkage of the matrix during the crystallization process, continuous fibers or long fibers are No problem occurs even when the fibers are composited, and the advantages of continuous fibers or long fibers can be effectively utilized. Furthermore, since the original glass is impregnated into continuous fibers or long fibers in a molten state, there is no need for mechanical mixing, and the shape can be created by making the continuous fibers or long fibers into a preform or by weaving them into cloth or tape. It's easy because you just have to turn it on. The content of continuous ceramic fibers or long fibers in the ceramic composite material is 30 to 50% by volume.
is preferred. If the content of continuous fibers or long fibers is less than 30% by volume, the strength cannot be sufficiently improved by these fibers, and if it exceeds 50% by volume, the fiber density becomes high, which impedes the penetration of the molten original glass and creates bubbles. This is because it may cause defects. In this way, the present invention does not perform mechanical mixing,
Since there is no shrinkage of the matrix during crystallization, the continuous fibers or long fibers of the ceramic can be introduced into the matrix with long fibers without being damaged. As a result, resistance to external stress and energy dispersion occur throughout the long fibers, significantly improving the strength and fracture toughness of the composite material. However, if continuous fibers or short fibers obtained by cutting long fibers into relatively short lengths are used as reinforcing materials, the resistance to external stress and the dispersion of energy will be localized, so the strength and toughness of the present invention will not be improved. No significant improvement effect can be obtained. Note that since crystallized glass has oxidation properties, for example, when non-oxide fibers such as SiC are used, the surface is easily oxidized and deteriorates, such as producing SiO ₂ .
In order to prevent this deterioration and fully utilize the characteristics of ceramic fibers, it is necessary to use Al ₂ O ₃ and other materials with high oxidation resistance.
It is preferable to use continuous fibers or long fibers of oxide ceramics such as ZrO ₂ containing 10% by weight or more of oxygen. Further, by using continuous fibers or long fibers of oxide ceramics, the interface with crystallized glass is strengthened, and a synergistic effect of improving the strength of the composite material can be obtained. [Example] Example 1 Al ₂ O ₃ with a diameter of 5 μm and a tensile strength of 200 Kg/mm ²
Woven fabric consisting of continuous fibers of and the same length of Al ₂ O ₃
MgO− containing TiO ₂ , ZrO ₂ , and SnO ₂ is used to form pine-like molded bodies made of short fibers of 0.5 to 2.0 cm.
The original glass powder was melted and impregnated by heat treatment at 1400°C for 3 hours in the atmosphere together with the Al ₂ O ₃ -SiO ₂ -based crystallized glass powder (100 mesh or less). Thereafter, the glass was crystallized at 1200°C to precipitate a crystalline phase mainly consisting of cordierite phase. The properties of the obtained composite material are shown in Table 1.

[Table] These results show that the strength and fracture toughness are greatly improved by crystallizing the glass in the matrix, and that even if the matrix is made of the same crystallized glass, the fibers contained therein are continuous fibers. It can be seen that this type has better strength and fracture toughness. Example 2 Li ₃ O-SiO ₂ -Al ₂ O ₃ -based crystallized glass powder (200
ZrO ₂ continuous fibers were sequentially immersed in the slurry, which was then taken out, laminated, and dried. At that time, the amount of slurry impregnated was adjusted to create dried bodies with different fiber contents. Thereafter, each dried body was heated to 1400° C. in the atmosphere to melt and impregnate the original glass powder to form a composite, and further subjected to crystallization treatment at 900° C. The properties of the obtained composite are shown in Table 2. Table 2

〔Effect of the invention〕

According to the present invention, by using crystallized glass as a matrix and ceramic continuous fibers or long fibers with long fibers as a reinforcing material, the fibers are uniformly dispersed without being damaged or deteriorated, and the bending strength is increased. Approximately 85Kg/mm ² or more, K _IC is approximately
It is possible to provide a ceramic composite material with excellent strength and fracture toughness of 9 MPam _1/2 or more.

Claims (1)

[Scope of Claims] 1. A ceramic composite material comprising a matrix of crystallized glass and continuous fibers or long fibers of oxide ceramics contained in the matrix in an amount of 30 to 50% by volume. 2. The ceramic composite material according to claim 1, wherein the oxide ceramic contains 10% by weight or more of oxygen. 3 The composition of crystallized glass is Li ₂ O−SiO ₂ −
Al ₂ O ₃ , Na ₂ O−Al ₂ O ₃ −SiO ₂ , Na ₂ O−CaO−
MgO−SiO ₂ , MgO−Al ₂ O ₃ −SiO ₂ , PbO−ZnO
−B ₂ O ₃ , ZnO−B ₂ O ₃ −SiO ₂ , or SiO ₂ −B ₂ O ₃ −
The ceramic composite material according to claim 1, characterized in that it is any one of _Al2O3 - _MgO - _K2O -F. 4 Melt the original glass of crystallized glass and
1. A method for producing a ceramic composite material, which comprises impregnating continuous fibers or long fibers of oxide ceramics occupying 30 to 50% by volume to form a composite, and then subjecting the original glass to crystallization treatment.