JPS63399B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing heat-resistant and oxidation-resistant materials,
Specifically, a shaped sintered body made of non-oxide ceramics such as carbides, nitrides, silicon compounds, borides, metals, or composites of metals and non-oxides is bonded with vanadiosiloxane (V-O-Si). ) or a mixture mainly composed of the organic silicon polymer compound, which is impregnated or surface coated, and then heat-treated to produce a material with excellent heat resistance, corrosion resistance, and oxidation resistance. The organosilicon polymer compound containing a vanadiosiloxane bond, i.e., the polymer referred to in the present invention is a polymer previously disclosed in JP-A-56-147827, in which the coordinating atom adjacent to the polyvanadiosiloxane or vanadium atom is It is a novel organometallic polymer that contains vanadium chains (oxygen) and polysilane as raw materials, has carbon and silicon as the main skeleton components, and contains vanadiosiloxane bonds (V-O-Si). The organosilicon polymer is an organometallic polymer whose main chain skeleton consists of Si-C bonds and V-O bonds, and also partially contains vanadiosiloxane bonds (V-O-Si), and has a ratio of silicon atoms to vanadium atoms. The ratio is 3:1~
1000:1, and the side chain directly bonded to the silicon atom is a group selected from the group consisting of hydrogen atoms, methyl, ethyl, and phenyl groups, and the vanadium atom is bonded to the silicon atom via the oxygen atom. A novel organometallic polymer characterized by the fact that there are substantially no side chain organic groups directly bonded to vanadium atoms, and the organosilicon polymer has the same properties as conventional polycarbosilanes. It is a heat-softening substance that dissolves in organic solvents such as n-hexane, xylene, tetrahydrofuran, and benzene, and melts when heated at 60 to 300°C. Silicon carbide containing vanadium carbide is produced by heating to 800°C or higher in helium, ammonia, hydrogen, or hydrocarbon gas. The present inventors have filed Japanese Patent Application No. 52-127630
Compared to the organosilicon polymer containing a portion of siloxane bonds previously disclosed in No. 61299), silicon carbide containing a portion of vanadiosiloxane bonds and containing vanadium carbide can be produced by heating in a non-oxidizing atmosphere. The present invention was completed based on the discovery that the resulting organosilicon polymer having vanadiosiloxane bonds provides superior properties as a heat-resistant, oxidation-resistant reinforcing impregnating agent and coating material for refractories. When the organosilicon polymer having vanadiosiloxane bonds was heated at 1400°C for 1 hour in an argon stream, graphite was identified in addition to carbide by X-ray diffraction, which suggests that the presence of this excess carbon is due to the presence of this excess carbon. Therefore, silicon (Si), vanadium (V), boron (B), titanium (Ti), aluminum (Al),
Chemically bonds to metal elements such as zirconium (Zr), hafnium (Hf), thorium (Th), niobium (Nb), molybdenum (Mo), tungsten (W), chromium (Cr), and tantalum (Ta). As a result, it can form a carbide that is effective for forming strong bonds, and therefore has strong adhesion to metals and non-oxide ceramic sintered bodies containing these metal atoms. It also exhibits strong adhesion to clean SiC and carbon surfaces through chemical bonding.
It also shows chemical bonds with carbides other than silicides and SiC. Furthermore, although nitrides and borides do not show chemical bonds in the commonly performed sintering process, silicon carbide containing vanadium carbide produced from the organosilicon polymer exists undamaged. can produce physical entanglement bonds with nitrides and borides. In this way, due to the chemical bonding between the organosilicon polymer having a vanadiosiloxane bond and the above-mentioned metal, carbide, silicide, or carbon, and for nitrides and borides, it is possible to form the organosilicon polymer by heating. Impregnation,
The present inventors have discovered that coating and other methods are extremely effective in improving the oxidation resistance and corrosion resistance of ceramics, metals, and composite materials thereof, and based on this discovery, the present invention was completed. is the present invention. Furthermore, in the present invention, not only organosilicon polymer compounds containing vanadiosiloxane bonds but also non-oxidized compounds such as carbides, nitrides, silicon compounds, and borides can be used from the viewpoint of chemical bonding, expansion property approximation, and integration. The performance as a coating agent can be improved by mixing a powder material of a composite of physical ceramic metal or non-oxide ceramic and metal, and it also includes refractories whose surfaces are coated with the powder material. . In all cases, the materials obtained by the production method of the present invention have significantly improved oxidation resistance and strength, as well as improved erosion resistance, compared to molded products not subjected to the treatment of the present invention. Shows excellent performance with improved performance. Application fields of the ceramic material that can be provided by the present invention include engines, blades, nose cones,
High temperature parts such as heat exchangers, sealing materials, packing materials,
These include wear-resistant parts such as bearing materials and brake materials, parts that require corrosion resistance such as tanks, ducts, pipes, and valves, and other electrical materials, electronic materials, piezoelectric materials, and nuclear power materials. The present invention will be explained below with reference to Examples. Example 1 A silicon nitride sintered body (200 x 100 x 20 mm) (1) obtained by reaction sintering was first prepared in Japanese Patent Application Laid-Open No. 56-147827.
It was immersed in a solution of 70 parts by weight of an organosilicon polymer produced from the acetylacetone complex of vanadium and polysilane described in the above publication and 30 parts by weight of solvent n-hexane, and treated in a pressurized impregnation container at 10 atmospheres for 3 hours. The sample was taken out, n-hexane was removed by evaporation in the air, and the remaining hexane was completely removed by heating in the air at 100°C for 5 hours. At the same time, the organosilicon polymer was crosslinked and infusible, and then heated in a nitrogen stream.
It was heated and fired at 1450℃. Comparing the characteristics of the product that has undergone this operation once (2), the product that has been performed twice (3), and the product that has undergone this operation three times (4), (2) has stronger strength compared to (1). The oxidation resistance, decomposition resistance to molten iron, and erosion resistance to converter slag have increased, and those that have been treated many times have also increased their properties. The results are summarized in Table 1.

[Table] Example 2 A porous silicon carbide sintered body (φ25 x 100 mm) (5) that uses a commercially available heating element, etc.
70 parts by weight of the organosilicon polymer produced using the vanadium acetylacetone complex described in No. 049581 and polysilane as raw materials, and 30 parts by weight of xylene as a solvent.
parts by weight of the solution, put it directly into a rubber mold, and used an isostatic press.
After pressure impregnation at a pressure of 500 kg/cm ² for 3 minutes, the sample was taken out, left in the air at room temperature, and heated at 100°C for 5 hours to completely remove xylene and at the same time cross-link and infusible the organosilicon polymer. Heat treatment was performed at 1300°C in an Ar stream to obtain (6). (6) 800℃
In the heat-treated product described below, the heated organosilicon polymer having vanadiosiloxane bonds of the present invention is in an unstable state and is easily oxidized. When (6) is heated above 2000℃, a decrease in strength due to crystal growth is observed. The same sample was similarly impregnated with an organosilicon polymer containing a portion of siloxane bonds, which was produced by reacting polysilane containing phenyl groups with polyborosiloxane already disclosed in JP-A No. 54-61299, and heat-treated in a non-oxidizing atmosphere. Compared with (7), (6) showed even better oxidation resistance (1400℃) and corrosion resistance against molten pig iron at 1300℃. The test results are summarized in Table 2.

【table】

[Table] Example 3 The organosilicon polymer containing vanadiosiloxane bonds used in Example 1 was impregnated into a graphite electrode rod (8) and a graphite electrolyte plate (9) by the method described in Example 2, and then
The material was heat-treated at 1200°C in an Ar flow, and then the same polymer was melted and coated on the surface of the treated object, and then heated to 1450°C in an Ar flow. As a result of comparing the oxidation resistance of the treated product of (8) as (10) and the treated product of (9) as (11) by heating in the atmosphere, the oxidation loss rate was compared to that of the untreated product at 800℃ for 2 hours. All treated products showed 1/10 to 1/18, and the oxidation loss rate in air at 1000°C was also 1/5 to 1/10. The above results are summarized in Table 3.

[Table] Example 4 100 parts by weight of the organosilicon polymer partially containing vanadiosiloxane bonds used in Example 2 was added to 50 parts by weight.
Dissolved in THF (tetrahydrofuran) and added 10 parts by weight of Si powder with an average particle size of 3μ and a petroleum solvent (boiling point
5 parts by weight (150-190°C) were added and wet-mixed in a pot mill to partially volatilize THF to obtain a viscous solution. When this is applied to the surface of a mild steel plate and a graphite electrolytic plate and heat treated at 900°C in a nitrogen stream, the oxidation resistance of the mild steel plate at 600°C for 20 hours becomes approximately 1/20 in terms of oxidation weight gain. In the case of graphite electrolytic plate, the oxidation loss rate at 500℃ for 2 hours is less than 1/20, 800℃,
The oxidation loss rate for 2 hours was also less than 1/20. Example 5 The viscous emulsion obtained in Example 4 was coated on a heat-resistant cast steel piece (SCH15) and heat-treated at 1000°C in a _N2 stream. The oxidation weight increase rate after 100 hours was less than 1/10, and the oxidation resistance of the heat-resistant cast steel was significantly improved. Example 6 The viscous solution obtained in Example 4 was applied to a TiC-Mo composite material sintered body made by hot-pressing TiC powder with metallic molybdenum whiskers and heated at 1200°C in a N ₂ stream. The oxidation weight gain of the heat-treated product in air at 1150°C for 100 hours was less than 1/10 of that of the non-coated product.

Claims (1)

[Claims] 1 Non-oxide ceramics, metals or composite materials of metals and non-oxide ceramics, with carbon and silicon as the main skeleton components, and vanadiosiloxane bonds (V-O-Si). 1. A method for producing a heat-resistant, oxidation-resistant material, which comprises impregnating or surface-coating the organic silicon polymer compound containing the compound, and then heat-treating the material in a non-oxidizing atmosphere at a temperature in the range of 800 to 2000°C. 2. The method for producing a heat-resistant, oxidation-resistant material according to claim 1, wherein the steps of impregnation or surface coating and heat treatment in a non-oxidizing atmosphere are repeated two or more times. 3 Non-oxide ceramics, metals or composite materials of metals and non-oxide ceramics, organosilicon polymer compounds whose main skeleton components are carbon and silicon and which contain vanadiosiloxane bonds (V-O-Si). The surface is coated with one or a mixture of two or more of non-oxide ceramic powder, metal powder, or composite powder of metal and non-oxide ceramic, and then heated at a temperature of 800 to 2000°C in a non-oxidizing atmosphere. A method for producing a heat-resistant and oxidation-resistant material, characterized by heat treatment within a range. 4. The method for producing a heat-resistant, oxidation-resistant material according to claim 3, wherein the steps of impregnation or surface coating and heat treatment in a non-oxidizing atmosphere are repeated two or more times.