The bonding has the job of retaining the grain within the grinding wheel until the grinding process blunts the grain particle; at this point, the bonding should release the grain, thus presenting a new and sharp particle. The bonding type and the percentage of bonding used depends on the grinding application.
Vitrified bonds are a mixture of kaolin, quartz, feldspar and glass. The mixture of these components determines the bond characteristics. Vitrified bonds are resistant to oil and soluble oil; however, they are brittle and fragile. The ensuing grinding pressure breaks down the bond.