High-strength silicon carbide ceramic and preparation method thereof

Abstract

The invention relates to a ceramic material. The invention relates to high-strength silicon carbide ceramic. The high-strength silicon carbide ceramic comprises the following components in parts by weight: 70-80 parts of silicon carbide powder, 10-20 parts of silicon carbide fibers, 20-25 parts of a binder, 5-10 parts of a pore-forming agent, 5-10 parts of a sintering aid, 5-10 parts of a dispersing agent and 2-3 parts of a toughening agent. The invention also provides a preparation method of the high-strength silicon carbide ceramic. The preparation method comprises the following steps: uniformly mixing raw materials to obtain raw material slurry, then carrying out vacuum treatment on the raw material slurry, injecting the ceramic slurry subjected to vacuum degassing into a mould, sealingthe mould, carrying out heating, carrying out heat preservation, then carrying out natural cooling, carrying out drying in a drying oven for 12-72 hours to obtain a ceramic biscuit, and carrying outsintering treatment on the ceramic biscuit, wherein the time of the sintering treatment is 1-5 hours, and the sintering temperature is 1500-1800 DEG C. The high-strength silicon carbide ceramic has the advantages that the pores in the silicon carbide ceramic are uniform and the silicon carbide ceramic has high strength.

Description

technical field [0001] The invention relates to a ceramic material, in particular to a high-strength silicon carbide ceramic and a preparation method thereof. Background technique [0002] Ceramic materials are a class of inorganic non-metallic materials made of natural or synthetic compounds after forming and high-temperature sintering. [0003] material. It has the advantages of high melting point, high hardness, high wear resistance and oxidation resistance. It can be used as structural material, tool material, and because ceramics also have some special properties, they can also be used as functional materials. [0004] Silicon carbide (SiC) is smelted at high temperature in a resistance furnace using raw materials such as quartz sand, petroleum coke (or coal coke), wood chips (salt is required to produce green silicon carbide), and the like. Silicon carbide also exists in nature as a rare mineral, moissanite. Silicon carbide is also called moissanite. Among the non...

AI Technical Summary

Problems solved by technology

In the existing methods for preparing porous silicon carbide ceramic materials, some processes are relatively simple, but the pore size and porosity cannot be effectively controlled, and it is difficult to prepare porous ceramics with a porosity higher than 80% and oriented pores; some processes require Exclude organic matter in the preparation process to form a pore structure. Although the porosity and pore size are controllable within a certain range, it is also difficult to prepare porous silicon carbide ceramics with high porosity. In addition, the exclusion of organic matter is not friendly to the environment; using polycarbosilane as Precursors enable the preparation of porous SiC ceramics at lower temperatures, but are expensive to prepare

On the other hand, the above-mentioned preparation method is difficult to realize the preparation of porous silicon carbide ceramics with complex shapes. To prepare parts with complex shapes, large subsequent mechanical processing is required, which greatly increases the production cost.

In addition, due to the poor sintering performance of silicon carbide, the mechanical properties of porous silicon carbide ceramics prepared by existing methods are low. When the porosity of the finished product reaches 50%, the strength is often lower than 40MPa, which severely limits the porous carbonization. Application of silicon ceramics