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

Abstract

The invention discloses a polycrystalline B4C-diamond 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 diamond powder are used as raw materials, and the polycrystalline B4C-diamond double-layer composite material is prepared by purifying the raw materials, pre-pressing and forming the raw materials, wrapping the pre-pressed and formed raw materials with a metal wrapping body, assembling a high-pressure assembly unit, placing the high-pressure assemblyunit in high-pressure equipment and sintering under high-temperature and high-pressure conditions. The polycrystalline B4C-diamond double-layer composite material has a polycrystalline diamond and polycrystalline B4C double-layer structure, the diamond layer and the B4C layer are compounded together through high-temperature and high-pressure sintering, the two layers of polycrystalline materialsare tightly combined, the grain size distribution is uniform, the density is high, the characteristics of high hardness and high fracture toughness of diamond are achieved, and the advantages that B4Cis easy to sinter and small in density are combined.

Description

technical field [0001] The present invention relates to a kind of polycrystalline B 4 C—a diamond 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 Because of its low density, high strength and good chemical stability, C is used in wear-resistant materials, ceramic reinforcement phases, especially in light armor, reactor neutron absorbers, etc.; in addition, it is used in phases with diamond and cubic boron nitride Compared with boron carbide, it 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 block has low fracture toug...

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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 Because of its low density, high strength and good chemical stability, C is used in wear-resistant materials, ceramic reinforcement phases, especially in light armor, reactor neutron absorbers, etc.; in addition, it is used in phases with diamond and cubic boron nitride Compared with boron carbide, it 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 block has low fracture toughness and poor high temperature stability (basically stable in air environment below 800°C, and will be oxidized to form boron oxide in gas phase loss at higher temperatures, resulting in its instability). limited to B 4 Large-scale applications of C

[0004] Diamond is the hardest substance known in nature. It has extremely high wear resistance, compressive strength, and heat dissipation rate. It is a superhard material widely used in industry; diamond single crystal is expensive and has a dissociation surface. In many fields, polycrystalline diamond materials with higher cost performance are used to replace diamond single crystals; traditional synthetic diamond polycrystalline sintered bodies are sintered at high pressure and high temperature after uniform mixing of synthetic diamond powder and Co, Ni and other metal powders. A composite polycrystalline superhard material, which exhibits isotropy, high hardness and toughness macroscopically, and has better application performance than single crystal in some aspects, and is widely used in non-ferrous metals, non-ferrous alloys and ceramics Cutting and processing of materials, oil and gas and mining exploration, wooden floor processing and other fields, but the diamond powder used to prepare polycrystalline diamond is expensive, which limits the large-scale application of polycrystalline diamond 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 combined with polycrystalline diamond to obtain polycrystalline B 4 C—Diamond double-layer composite material can not only have the characteristics of high hardness and high fracture toughness of diamond, but also have the characteristics of B 4 C has the advantages of low cost, low density, and easy sintering. However, there is no preparation of polycrystalline B 4 C—Report on Diamond Double Layer Composite Material

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