Difference Between SPS and Traditional Sintering
The pressurization method of spark plasma sintering is similar to hot pressing sintering. Both methods apply axial load to the sample during high-temperature sintering to accelerate sample densification. However, the heating method of spark plasma sintering is significantly different from that of traditional sintering methods. In traditional sintering, a heat source such as a heating resistor or silicon carbon rod is usually used to heat the sample by thermal radiation or convection. In spark plasma sintering, the sintering current flows through the sample and releases Joule heat. This allows the sample itself to be heated directly. At the same time, the entire heating system mostly uses graphite components, which have a small heat capacity and high thermal conductivity, allowing the sample to heat up quickly.
Advantages of Spark Plasma Sintering
Therefore, spark plasma sintering has advantages that are difficult to match with traditional sintering methods:
- Short sintering time. Spark plasma sintering can achieve material densification in a very short time. It takes about 2~10 minutes, while conventional sintering takes several hours;
- (2) Fast heating rate. It is easy to achieve a heating rate of tens of degrees Celsius per minute or even hundreds of degrees Celsius per minute;
- (3) High sintering pressure. From tens of MPa to 1GPa, densification can be easily achieved for some difficult-to-sinter materials such as WC and SiC;
- (4) Low sintering temperature. Compared with traditional sintering, the sintering temperature of spark plasma sintering can be reduced by 100~300℃, which is conducive to the preparation of some materials that are easy to decompose at high temperatures;
- (5) No powder preforming is required, and the sample can be directly formed during the sintering process.
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