Influence of Li2O Addition on the Performance of Vitrified Bond and Vitrified Diamond Composites.

In order to develop high-performance diamond wheels, the vitrified bond with different contents of Li₂O addition and corresponding diamond composites were prepared. The experimental results show that the addition of a small content of Li₂O leads the formation of the mullite phase in vitrified bond. When the Li₂O content is 3wt%, the mullite content in the vitrified bond reaches the maximum. Whereas, the vitrified bond turns into a pure glass phase when the Li₂O content further increases to 5wt%. The softening temperature of vitrified bond, wetting angle between the vitrified bond and the diamond film decrease with the increasing of the Li₂O content. The softening point of the vitrified bond with 5wt% Li₂O is 537 °C and the contact angle is 32°, which are 44 °C and 44° lower than those of the sample without Li₂O. The CTE (coefficient of thermal expansion), the flexural strength and hardness of the diamond composite sample first increase and then decrease with the increasing of the Li₂O content. When the Li₂O addition is 3wt%, the flexural strength and hardness of the composites reaches the maximum values of 93 MPa and 98 HRB, respectively, which are 43.1% and 12.6% higher than those of the sample without Li₂O. [ABSTRACT FROM AUTHOR]