Sol-gel synthesis of borosilicate vitrified bond for Diamond grinding wheel

Abstract

Vitrified bond diamond composites were prepared by using commercial diamond grits and a low melting sodium borosilicate glass vitrified bond. Sodium borosilicate glass with composition: 50 SiO2. 20 B2O3 .10 Al2O3. 10 Na2O, 8 K2O and 2 ZnO (mol%) was synthesised through sol-gel process using TEOS , Boric acid , NaNO3, Al2O3, KNO3, Zn(NO3) and HNO3 as catalyst.
Thermal decomposition behaviour of gel was studied using TG & DSC. The glass forming temperature was identified and characterised by XRD studies at different stages. Initial gel shows very little boron in glassy network. A complete amorphous glass was obtained heating the gel at 700˚C.
Calcined glass powder was used as a bonding material for diamond grits. Bonding behaviour between diamond & glass was investigated by optical microscopy. An optimal amount of vitrified bond for diamond grits with 250 micron was 5:2 (wt%) diamond: bond and sintering the composite in air atmosphere at 650 to 700 C