Preparation method of normal pressure-sintered silicon carbide ceramics

Abstract

The invention discloses a preparation method of normal pressure-sintered silicon carbide ceramics, which adopts a solid normal pressure sintering method and takes submicro silicon carbide powder, graphite powder and boron carbide powder as main materials. The method comprises the following steps: 1) material grinding is carried out by adopting a staged ball milling mode, firstly, the main raw materials are ball-milled by adding water under the environment of the pH value being 10-12 to lead the agglomerated silicon carbide micro powder and other main raw materials to be evenly dispersed; then a plasticiser, a lubricant and water soluble phenol resin are added and ball-milled for a period of time; and finally a caking agent is added for ball milling; 2) spray granulation technology is adopted for carrying out granulation on the silicon carbide slurry; (3) the materials after granulation are maintained under constant temperature and humidity; (4) double-sided compression moulding is carried out on the maintained materials; (5) a staged drying mechanism is adopted for drying the molded body; and (6) the silicon carbide body is put in a vacuum firing furnace for being subjected to two times of sintering by taking the argon as protective gas. The silicon carbide ceramics prepared by the method have superior performance, corrosion resistance and long service life, and are applicable to commercial process.

Description

technical field [0001] The invention relates to a preparation method, in particular to a preparation method of normal pressure sintered silicon carbide ceramics. Background technique [0002] As a high-temperature structural ceramic, silicon carbide ceramics have many excellent properties, such as wear resistance, high thermal conductivity, heat resistance, corrosion resistance, and excellent mechanical and thermal properties. Silicon carbide ceramics have been widely used in machinery, electronics, petrochemical, metallurgy and other industrial fields, as well as the national defense industry, and have been recognized internationally as the fourth basic material since metal, alumina, and cemented carbide. [0003] Silicon carbide ceramic materials used in different fields have different requirements for performance and require different preparation methods. At present, the preparation methods of silicon carbide can be divided into several categories: reaction sintering, at...

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Problems solved by technology

Relatively speaking, the liquid-phase atmospheric pressure sintering method has a lower sintering temperature and comparable mechanical properties to hot-press sintering, but because the prepared product contains more additives, such as patent No. 200410062956. Silicon carbide ceramics liquid phase sintering method” discloses a liquid phase normal pressure sintering method, using aluminum nitride-rare earth oxide as a sintering aid, so that its corrosion resistance is not high enough in complex and harsh environments, so the product The service life is not high enough, and it also limits its application in some industries that require high purity

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