A tungsten/silicon nitride/tungsten symmetrical layered gradient composite material and its rapid preparation method and application

Abstract

The invention discloses a W / Si 3 N 4 / W symmetrical layered gradient composite material and its rapid preparation method and application, belonging to the technical field of ceramic matrix composite material preparation, the invention adopts SPS sintering technology to prepare W / Si 3 N 4 / W symmetrical layered gradient composite material, this method introduces an electric field on the basis of the temperature field and pressure field, which can play a role in the plasma activation of the raw material, so that it can be produced under the conditions of lower sintering temperature and shorter holding time. Dense multi-phase ceramic materials can be quickly prepared; at the same time, the activation of the plasma also helps the diffusion of atoms, which in turn can promote the formation of W and Si 3 N 4 interlayer bonding to achieve W and Si 3 N 4 This method has the advantages of fast heating rate, low sintering temperature, and short holding time. This method can quickly prepare W / Si with high density, low impurity content, and good interface bonding. 3 N 4 / W Symmetric layered gradient composites.

Description

technical field [0001] The invention belongs to the technical field of preparation of ceramic matrix composite materials, in particular to a W / Si 3 N 4 / W Symmetric layered gradient composite materials and their rapid preparation methods and applications. Background technique [0002] Silicon nitride (Si 3 N 4 ) Ceramics have excellent mechanical properties and chemical stability such as high temperature resistance, good thermal shock resistance, high insulation coefficient, high wear resistance, and corrosion resistance. Therefore, they are used in high-temperature structural materials, refractory materials, insulating materials and corrosion-resistant materials. There are broad application prospects in the field. In practical applications, Si is usually required 3 N 4 Combined with metal components such as heat-resistant alloys or stainless steel. And the thermal expansion coefficient of alloy or stainless steel (10~16×10 -6 / ℃) is much larger than that of Si 3 N ...

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Problems solved by technology

But this method also has some disadvantages: first, the automatic grouting molding equipment of this method is complex and expensive, and the lamination process is difficult to realize; second, the sintering process has a high sintering temperature, a long holding time, and requires Third, some elements will segregate on the interface of the sample sintered by this method, resulting in stress concentration and easy formation of defects such as interface cracks, which directly affect the mechanics, physics, chemistry and electricity of the material. Chemical properties; Fourth, due to the addition of some polymer dispersants during automatic grouting, large pores appeared in the middle layer of the sample after sintering, resulting in problems such as low strength and poor air tightness

Therefore, the ceramic / metal gradient materials obtained by the existing preparation methods are still difficult to be used as long-term high-temperature insulating packaging materials for liquid metal batteries, and some structural / functional integrated components.

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