Method for preparing lower volume fraction porous silicon carbide ceramic body

Abstract

The invention discloses a method for preparing a lower volume fraction porous silicon carbide ceramic body. According to the method, water in an acrylamide gel system formed by adopting a conventional ceramic gel injection molding process is replaced by silica sol to form a silica sol-acrylamide double gel network system. A gel blank is enabled to have a certain strength by controlling the ratio of the silica sol to acrylamide and adding graphite powder with a certain proportion in slurry; and meanwhile, by using a silica sol-gel network left by removing the gel, the blank is enabled to have a certain strength and the requirement of late infiltration metal on the strength of the blank body can be met. Due to the adoption of the graphite powder in the slurry, the setting phenomenon of carborundum particles due to low viscosity caused by overlow volume fraction in the gel process can be effectively avoided and the graphite powder can be burnt out in the air in the late stage of gel removal. According to the method, the porous silicon carbide ceramic body with the volume fraction being 15-45 percent, the strength being over 3MPa and the closed porosity being smaller than 0.5 percent can be prepared with lower cost.

Description

[0001] technical field [0002] The invention belongs to the research field of metal matrix composite materials, and relates to a method for preparing a low volume fraction porous ceramic green body. Background technique [0003] Low volume fraction (15~45vol%) silicon carbide particle reinforced aluminum matrix composites not only have good comprehensive mechanical properties, but also have excellent wear resistance, which is an ideal structure and wear-resistant material. However, the high hardness, high brittleness and other characteristics of this material make it difficult to process it into parts of the required shape by secondary machining, which greatly limits the wide use of this material. Therefore, it is very necessary to develop a near-net-shape process for this material. At present, the near-net shape process widely used at home and abroad is the liquid metal infiltration method, which is to prepare the porous reinforced phase ceramic body with the final shape ...

AI Technical Summary

Problems solved by technology

If the viscosity of the slurry is too high, it is difficult to form the green body, and if the viscosity of the slurry is too low, it will easily cause the solid particles to settle during the gel process, and the green body will shrink too much in the later stage, resulting in serious deformation of the green body.