Sintering process of silicon carbide ceramics - hot pressing sintering

The second sintering method for silicon carbide industrial ceramics is hot pressing sintering. Although this method has significant advantages, its disadvantages are also quite obvious. The process and equipment are relatively complex. Let's take a look at the ceramic factory together!

Introduction to hot press sintering:

Hot Pressed Sintering is a sintering method in which dry powder is filled into the model, and then pressurized and heated from a uniaxial direction to complete both molding and sintering simultaneously.

The characteristics of hot pressing sintering: Due to the simultaneous heating and pressure, the powder is in a thermoplastic state, which facilitates the contact diffusion and flow mass transfer of particles, resulting in a molding pressure of only 1/10 of that of cold pressing; It can also reduce the sintering temperature, shorten the sintering time, and resist grain growth, resulting in products with small grains, high density, and good mechanical and electrical properties. Without the need for sintering or forming additives, pure ceramic products can be produced. The drawbacks of hot pressing sintering are complex processes and equipment, strict production control requirements, high requirements for mold materials, high energy consumption, low production efficiency, and high production costs

In the mid-1950s, Norton Corporation in the United States began studying the effects of metal additives such as B, Ni, Cr, Fe, A 시 on SiC hot pressing sintering. The experimental results indicate that AI and Fe are effective additives for promoting the densification of SiC by hot pressing. Researchers have used AI2O3 as an additive and achieved the densification of SiC through the hot pressing sintering process, and believe that its mechanism is liquid-phase sintering. In addition, researchers have also obtained dense SiC ceramics by using B4C, B or B with C, Al203 with C, AI203 with Y2O3, Be, B4C with C as additives and using hot pressing sintering.

Research has shown that the microstructure, mechanical, thermal and other properties of sintered bodies vary depending on the type of additive used. For example, when B or B compounds are used as additives, the grain size of hot pressed SiC is small, but its strength is high. When Be is selected as an additive, hot-pressed SiC ceramics have a higher thermal conductivity.

Examples of using hot pressing as a means of manufacturing products include industrial ceramics such as alumina, ferrite, boron carbide, and silicon carbide.

Silicon carbide ceramics, as a machinable ceramic, have a wide range of applications and can be made into ceramic tubes, ceramic rods, etc

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