JPH11100269A - Low temperature produced mo(al, si)2 based material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high toughness material at a low temp. by molding and firing a powdery mixture prepared by adding a specific quantity of each Al powder and Mo powder into a MoSi2 powder. SOLUTION: The Al powder is added by 1-36 wt.% per total weight into the MoSi2 powder covered with a thin film of SiO2 oxidized in the atmosphere to allow the Al powder to react with SiO2 on the space to produce Al2 O3 and simultaneously Si metal and Mo (Al, Si)2 . Next, to remove the Si metal produced in the treatment, 1-80 wt.% Mo powder per total weight is added and mixed. The Mo(Al, Si)2 sintered compact is obtained by molding the MSiz-Al-Mo powdery mixture and firing the molding. And a Mo(Al, Si)2 member having no pores is obtained by adding 1-80 wt.% Mo powder per total weight into the MoSi2 powder, mixing and after heating at about 1,450 deg.C, impregnating with a molten Al for prescribed time as another producing method.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel material having high-density and high-toughness mechanical properties which can be produced at a low temperature, and which comprises an oxidation-resistant material and a heat-resistant material. It is intended to provide a material that can be used for many purposes, such as a material or a wear-resistant material. [0002] MoSi ₂ is excellent in oxidation resistance, TiB ₂ and M
A sintered material using o ₂ B ₅ or the like as an additive material is known as Japanese Patent No. 1504633, and a composite material having a high density as a SiC—Mo (Al, Si) ₂ material is known as Japanese Patent No. 2535768. . [0003] Since these materials have excellent oxidation resistance, they can be used as heaters for atmospheric furnaces and heat-resistant materials. If their properties are further improved, the range of use is expected to be further expanded. [0004] MoSi ₂ raw material powder is originally oxidized by atmospheric oxygen and covered with a thin film of SiO ₂ . Therefore, Mo described in Japanese Patent No.
Si ₂ -based ceramics contain a large amount of SiO ₂ and have the disadvantage that they are easily deformed at high temperatures. Patent No. 253
MoSi ₂ based ceramics described in No. 5768 is S
It is a material in which Mo (Al, Si) ₂ is infiltrated in order to lower the infiltration temperature with SiC as the main component so as not to contain iO ₂ ,
The temperature required for infiltration still requires a high temperature of 1700 to 2050 ° C. Low processing temperatures are required for industrial use. An object of the present invention is to provide a sintered body or an infiltrated body which retains the inherent oxidation resistance of MoSi ₂ and has improved mechanical properties by low-temperature treatment. [0005] The present inventor has proposed that MoSi can be used at a low temperature.
As a result of intensive studies on the production of the system ₂ material, Mo compacted by sintering a compact of a mixed powder of MoSi ₂ and 1 to 36 wt% Al, or by melting and impregnating Al into a MoSi ₂ powder compact. A method for producing (Al, Si) ₂ material has been found. Further, 1 to 80 wt% of Mo of the total weight is added to MoSi ₂ powder.
1 to 36 w of the total weight is added to the mixed powder obtained by mixing the powder.
The mixed powder to which t% Al powder is added is molded and sintered, or MoSi ₂ powder is added with 1 to 80 wt% of M
o The mixed powder to which the powder was added was formed into a compact, and it was found that a Mo (Al, Si) _2- based material could be produced by melt-impregnating Al, and based on these findings, the present invention was completed. . That is, according to the present invention, in order to use MoSi ₂ as a heat-resistant structural material, MoSi ₂ powder is
because it is covered with iO ₂ film, and adverse effects of SiO ₂ SiO ₂ coating as an impurity just composite, brittle at room temperature MoSi
_It further embrittles ₂ and easily deforms at high temperatures. Then, SiO of MoSi ₂ surface during processing ₂
The removal as a reaction product, yet is obtained by from MoSi ₂ high toughness of Mo (Al, Si) to generate a _2. More specifically, depending on the manufacturing process and the particle size of the powder, the oxygen content of the SiO ₂ coating the MoSi ₂ powder of # 200 to # 600 is 4 to 5 wt% of the total amount of MoSi _2.
It is. Therefore, the use of MoSi ₂ raw material powder # 600 and # 200, the MoSi ₂ -Al sintered, 1 wt the Al
%, The effect of addition is small because the amount of SiO ₂ that reacts with Al is too large. When 36 wt% of Al is added, SiO ₂ reacts with Al to form Al ₂ O ₃ , but at the same time,
Metal and Mo (Al, Si) ₂ are formed. MoSi ₂ is by the addition of Al Mo (Al, Si) range that can be dissolved in ₂ is a schematic 3 against MoSi ₂
6 wt%. Therefore, if it is added in an amount of 36% by weight or more, it remains as Al in the material, which is not preferable. [0008] The same material as described above can be produced by impregnating molten Al into a MoSi ₂ powder compact. In order to remove Si generated during the above-mentioned production, it is necessary to use a mixed powder of MoSi ₂ and Mo as a raw material powder. Therefore, depending on the amount of Si generated during processing,
When the amount of Mo is 1 wt% or less, a large amount of Si remains, and the effect of addition is small. On the other hand, if the content is more than 80 wt%, the amount of Mo is too large, so that the impregnation is not good. Therefore, the amount of Mo added is 1 to 8
0 wt%. In the sintering method of MoSi ₂ -Mo-Al system, MoSi ₂ -80 wt% Mo which does not leave Al in the material is used.
The maximum addition amount of Al is approximately up to 36 wt%. If more Al is added, the oxidation resistance of the material deteriorates. The material of the present invention is obtained by mixing the above-mentioned respective component powders,
It can be manufactured by a sintering method and an impregnation method known so far. For example, Mo was added to MoSi ₂ powder in an amount of 10 wt% based on the total amount, mixed, heated to 1450 ° C., and then impregnated with molten Al for 60 minutes. As a result, a dense material without pores was obtained. When the properties were measured, a three-point bending strength of 350 MPa and a fracture toughness value of 6.3 MPa ^1/2 were obtained. This example is shown in Table 1.
No.12. Table 1 shows other examples. Comparative Examples * 1 and * 15 in Table 1 are shown as comparative examples. Mo
The hot-pressed sintered body of only Si ₂ has a low fracture toughness of 1.5 MPam ^1/2 . In addition, there are many pores, and it is difficult to use them for heat-resistant structural materials. Although it is possible to impregnate Mo only powder with Al, it is inferior in oxidation resistance because it does not contain Si. [Table 1] As described above, according to the present invention, MoSi
After adding Al to the mixed powder of ₂ or MoSi ₂ and Mo, molding and sintering, or MoSi ₂ powder compact or MoS
By melting impregnated with Al in the compact of i ₂ and Mo mixed powder, it is possible to obtain a high toughness material at a low temperature.

Claims (1)

Claims 1. MoSi ₂ powder has a total weight of 1 wt% to 36 w.
Material obtained by molding and sintering a mixed powder to which t% Al powder has been added. 2. The MoSi ₂ powder has a weight of 1 wt% to 36 w of the total weight.
A material obtained by molding and sintering a mixed powder containing t% Al powder and Mo powder of 1 wt% to 63 wt% of the total weight. 3. A material obtained by melting and impregnating Al into a molded body of MoSi ₂ powder. 4. The MoSi ₂ powder has a weight of 1 wt% to 80 w.
A material obtained by forming a mixed powder to which t% of Mo powder is added and melting and impregnating Al. 5. A manufacturing method for manufacturing the material according to claim 1.