Preparation methods of MAX phase materials
There are many preparation methods for MAX phase materials. According to different final morphologies, there are different synthesis processes. The morphologies of MAX phase materials are generally massive, powdery and thin film.
Preparation of bulk MAX phase materials
For bulk MAX phase materials, chemical vapour deposition (CVD) is the earliest method to prepare this material. CVD technology requires higher synthesis temperature, higher production cost and lower production efficiency. Thereby, hot isostatic pressing sintering technology appeared later. Pampuch et al. prepared bulk Ti₃SiC₂ by hot isostatic pressing sintering. Although the production cycle is obviously shortened, impurities (mainly TiC) are easily produced in the production process, and the purity is not high. Until 1996, Barsoum et al. prepared Ti₃SiC₂ with high purity by hot pressing. In order to improve production efficiency, spark plasma sintering (SPS) has appeared again. Although the sintering process is similar to hot pressing, its requirement for raw materials has been reduced.
Compared with other methods, pressureless sintering is more suitable for industrial mass production. The earliest pressureless sintering is usually carried out by mechanical alloying pretreatment before pressureless sintering. But there are many impurities in this method. After that, Sun et al. tried to add Al in pressureless sintering, which made the density of the material increase significantly.
Preparation of powder MAX phase materials
For powdered MAX phase materials, oxidation reaction was the earliest method to prepare MAX phase materials. Later, after further research, the solid-liquid reaction method became a more suitable method.
For powdery MAX phase materials, the earliest preparation method is oxidation reaction. Later, after further research, the solid-liquid reaction method became a more suitable method.
Racault et al. who studied the powder MAX phase earlier, placed T powder, Si powder and C powder with a certain molar ratio in a vacuum silicon tube and heated it at about 1100°C for 10h. The product of solid phase reaction was a mixture of Ti₃SiC₂, TiSi₂ and TiC. After the mixture is obtained, TiSi₂ impurities are removed by HF gas, and the TiSi₂ is oxidized in air at 450°C for 10h. The TiO obtained from the oxidation reaction is removed by concentrated sulfuric acid to obtain the MAX phase powder with purity up to 95%.
Yang et al. explored the effects of these factors on the preparation of MAX phase by controlling different powder ratios, different temperatures and different holding times. The results showed that to obtain MAX phase powders with purity of more than 99wt%, the ratio of Ti powder, Si powder and TiC could be controlled at 1: (1.10~1.15) : 2. Vacuum insulation for 2h at 1250°C~1300C. In addition, Yang et al. replaced C powder and Si powder with polycarbosilane, mixed with Ti and TH, and conducted pyrolysis and further heat treatment under the condition of inert gas to obtain high-purity MAX phase materials.
Preparation of thin film MAX phase materials
Film-like MAX phase materials were first prepared by chemical vapor deposition. In 1972, Nicki I first prepared Ti Sic2 phase thin films by CVD, but no single phase was obtained. It is found that the thin film MAX phase material can be prepared by physical vapour Deposition (PVD). Using magnetron sputtering technology, Palmquist et al. successfully prepared Ti Sic 2 thin films at 900 C by three-source co-sputtering of I target, Si target and C target. At the same time, the cathode pulse arc and high-speed oxidation jet have some applications in the preparation of this material.
The results show that if the temperature is lower than 473K, the material cannot be prepared. However, in a certain range of more than 434k, low temperature nano-film can be prepared. The material has high wear resistance, corrosion resistance and strong conductivity. TRUNNANO (Luoyang Trunnano Tech Co., Ltd ) is a professional Titanium silicon carbide manufacturer with over 12 years experience in chemical products research and development. If you are looking for high quality Titanium silicon carbide, please feel free to contact us and send an inquiry.
