Influence of heat treatment temperature on bonding and oxidation resistance of diamond particles coated with TiO2 film

Abstract

In this paper, TiO 2 films were coated on the surface of diamond particles using a sol-gel method. The effects of heat treatment temperature on the morphology, composition, chemical bonds, oxidation resistance and compressive strength of diamond particles coated with TiO 2 films were characterized through scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, thermogravimetric-differential scanning calorimetry and compressive strength test. The results showed that when the temperature reached 600°C, the amorphous TiO 2 on the diamond particles surface exhibited as a dense anatase film and the Ti-O-C bond formed between TiO 2 and the diamond substrates. When temperature reached 800°C, TiO 2 films were still in anatase phase and part of the diamond carbon began to graphitize. The graphitizated carbon can also form the Ti-O-C bond with TiO 2 film, although TiO 2 film would tend to crack in this condition. Meanwhile, the temperature had a serious influence on the oxidation resistance of diamond particles coated with TiO 2 films in air. When the heat treatment temperature reached 600°C, the initial oxidation temperature of the coated diamond particles reached the maximum value of 754°C. When the diamond particles were oxidized at 800°C for 0.5 h in air, the weight loss rate reached the minimum value of 6.7 wt% and the compressive strength reached the maximum value of 15.7 N.

Direct Laser Writing of Crystallized TiO2 and TiO2/Carbon Microstructures with Tunable Conductive Properties

“…Usually, the D band is positioned at 1325 cm −1 . However, a shift of approximately 35 cm −1 was found in the Raman spectrum, which was attributed to the formation of the TiOC bond . It was also observed that the disordered carbon peaks had significantly decreased with the increased exposure power, which was explained by the oxidation of the carbon species under high laser fluency in the presence of oxygen from air.…”