Method for preparing large-aperture three-dimensional network SiC ceramic material

Abstract

The invention belongs to the technical field of ceramic materials, and in particular relates to a method for preparing a large-aperture three-dimensional network SiC ceramic material. The present invention is to mix SiC powder and B4C powder, add ammonia water, sugar, acrylamide, N, N-methylenebisacrylamide and water ball mill and mix evenly to form SiC mixed slurry, and add surface activity to SiC mixed slurry Agent, foaming agent hydrogen peroxide and binder, stir well and add initiator gel to foam to obtain foam gel, under the protection of inert atmosphere, heat-preserve and sinter the foam gel at 1950-2040°C for 0.5-1h to obtain Large-aperture three-dimensional network SiC ceramic material. The invention can prepare macroporous three-dimensional network silicon carbide. By controlling the concentration and addition amount of polyvinyl alcohol, the pore size can be controlled. At the same time, the addition amount of hydrogen peroxide aqueous solution can control the porosity and pore size, and the use of surfactant is effective. Improving the connectivity of large pores is simple, reliable, does not require large fixed investment, and has good application prospects.

Description

technical field [0001] The invention belongs to the technical field of ceramic materials, and in particular relates to a method for preparing a large-aperture three-dimensional network SiC ceramic material. Background technique [0002] Silicon carbide porous ceramic is a kind of ceramic material with both structure and function. It not only has the excellent performance of ceramic matrix, but also has large porosity, pore surface area and adjustable pore shape, pore size, and pore size. It is distributed in three-dimensional space and has connectivity. At the same time, it also has matching thermal, electrical, magnetic, optical and chemical properties. The more attractive application of silicon carbide ceramics with a macroporous structure is that it can be used as a filter material for gases, liquids (such as molten metal), and solid particles under harsh environmental conditions, as a catalyst carrier, and can also be used in Solar receptor materials, physical and c...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are also obvious: first, the pore size and pore shape depend on the pore size and pore shape of the template; secondly, the synthesis steps are relatively cumbersome, in addition to the ceramic sintering steps, some also involve template preparation and pretreatment, Including pore forming, carbonization and other steps; in addition, the template skeleton used to prepare macropores is generally thicker, affected by solid diffusion reactions, silicidation and carbothermal reduction are generally incomplete, and the introduction of excessive reactants will cause carbonization of the finished product The impurity of silicon ceramics, in order to obtain purer silicon carbide materials, post-processing steps are inevitable

However, using various sponges as templates will easily generate wall holes (left after the decomposition of the sponge skeleton), which is not conducive to improving the mechanical properties of the sintered ceramics.

Therefore, these methods all have disadvantages such as complex process, high cost and closed pores, and their use is limited to a certain extent.

However, the current template-free method to prepare porous materials mainly has the disadvantages of high cost, poor three-dimensional connectivity, many closed pores, and small pore size, so it is not widely used.

Images