Influence of TiO2 amount on the interfacial wettability and relevant properties of vitrified bond CBN composites

The influence of TiO2 amount on the microstructure and relevant properties of SiO2-Al2O3-B2O3-Na2O-Li2O-BaO vitrified bond and vitrified bond CBN composites were systematically studied via SEM, EDS, FTIR, and XPS. Results indicated that adding TiO2 could regulate the quantity of β-quartz solid solution and rutile crystals in the vitrified bond and considerably affect the thermal properties and mechanical strength of this bond. Under sintering temperature, the dense B2O3 oxide layer on the CBN surface diffused into vitrified bond and reacted with Ti4+ enriched at the interface to form a strong chemical Ti-B bond. This reaction extensively improved the interfacial wettability between the CBN and the vitrified bond. When the TiO2 amount was 6wt.%, the interfacial wettability significantly improved, and the wetting angle decreased from 68° to 43°. The flexure strength and hardness of the composites were 116.18 MPa and 128 HRB, which were 48.49% and 34.74% higher than those of the basic-formula composites, respectively.