Polycrystalline B4C-SiC double-layer composite material and preparation method thereof

Abstract

The invention relates to a polycrystalline B4C-SiC double-layer composite material and a preparation method thereof, and belongs to the field of inorganic non-metallic materials. According to the method, B4C polycrystalline blocks or powder and SiC polycrystalline blocks or powder are used as raw materials, purification treatment and pre-press molding are carried out on the raw materials, the pre-press molded raw materials are wrapped by a metal wrapping body, a high-pressure assembly unit is assembled and put into ultrahigh-pressure equipment, and sintering is carried out at the high temperature of 600-2300 DEG C and at the high pressure of 1-25GPa to obtain the polycrystalline B4C-SiC double-layer composite material. The polycrystalline B4C-SiC double-layer composite material prepared bythe method has a polycrystalline SiC and polycrystalline B4C double-layer structure, the SiC layer and the B4C layer are sintered together at high temperature and high pressure, the two layers of polycrystals are tightly combined, the grain size distribution is uniform, and the density is high; and the polycrystalline B4C-SiC double-layer composite material not only has the characteristics of higher hardness, higher fracture toughness and low density of B4C, but also has the advantages of low cost and easiness in sintering of SiC.

Description

technical field [0001] The present invention relates to a kind of polycrystalline B 4 The invention discloses a C—SiC double-layer composite material and a preparation method thereof, which belong to the field of inorganic non-metallic materials. [0002] technical background [0003] The molecular formula of boron carbide is B 4 C, gray-black micropowder, is one of the three hardest materials known (the other two are diamond and cubic phase boron nitride), B 4 C has the characteristics of high hardness, high fracture toughness, low density and good chemical stability. It is used in wear-resistant materials, ceramic reinforcement phases, especially in light armor, reactor neutron absorbers, etc.; in addition, it is used with diamond, cubic Compared with boron nitride, boron carbide is easy to manufacture and relatively low in cost, so it is more widely used, and in some places it can replace expensive diamonds in grinding, grinding, drilling, etc.; however, B 4 As a struct...

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Problems solved by technology

[0003] The molecular formula of boron carbide is B 4 C, gray-black micropowder, is one of the three hardest materials known (the other two are diamond and cubic phase boron nitride), B 4 C has the characteristics of high hardness, high fracture toughness, low density and good chemical stability. It is used in wear-resistant materials, ceramic reinforcement phases, especially in light armor, reactor neutron absorbers, etc.; in addition, it is used with diamond, cubic Compared with boron nitride, boron carbide is easy to manufacture and relatively low in cost, so it is more widely used, and in some places it can replace expensive diamonds in grinding, grinding, drilling, etc.; however, B 4 As a structural material, C blocks have poor high-temperature stability (it is basically stable below 800°C in an air environment, and at higher temperatures it will oxidize to form boron oxide and lose it in the gas phase, resulting in its instability), which limits B to a certain extent. 4 Large-scale applications of C

[0004] Silicon carbide (α-SiC) ceramics have good chemical corrosion resistance, good wear resistance, small friction coefficient and high temperature resistance, and are an important class of ceramic materials; silicon carbide has four main application areas: 1. Abrasives and cutting tools : Due to the durability and low cost of silicon carbide, it is used as a common abrasive in modern industrial processing; 2. Structural materials: Silicon carbide has the potential to be used as a structural material instead of nickel superalloys to manufacture turbine blades or nozzle blades; 3. Astronomy: silicon carbide It can be used as a mirror material for astronomical telescopes; 4. Catalyst carrier: the anti-oxidation properties of silicon carbide itself make it a carrier for heterogeneous catalysts; silicon carbide has a large output, is easy to sinter, and has low production costs, but polycrystalline silicon carbide blocks The fracture toughness of SiC as a structural material is low, which limits the application of SiC as a structural material to a certain extent.

[0005] Composite material is a new material formed by optimizing the combination of material components with different properties by using advanced material preparation technology. Composite material has two or more material components with different chemical and physical properties. Obvious interface; composite materials have structural designability, and composite structure design can be carried out; composite materials not only maintain the advantages of the properties of each component material, but also can obtain comprehensive properties that cannot be achieved by a single component material through the complementarity and correlation of the properties of each component performance; if the polycrystalline B 4 C is compounded with polycrystalline SiC to obtain polycrystalline B 4 C—SiC double-layer composite material, not only can have B 4 C has the characteristics of high hardness, high fracture toughness, and low density, and it can also have the advantages of low cost and easy sintering of SiC. However, there has been no preparation of polycrystalline B 4 Report on C—SiC Bilayer Composites

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