Grinding of WC-Co cermets using hexagonal boron nitride nano-aerosol

WC-Co cermets (ceramic-metal composites) were ground by a resin bonded diamond grinding wheel using hexagonal boron nitride (hBN) nano-aerosol to improve the grindability. This is a new generation grinding fluid and was produced by dispersing nano-sized hBN platelets in deionized water. Small quantity cooling-lubrication (SQCL) technology was employed to deliver hBN nanofluid in the form of nano-aerosol so that volumetric consumption rate could be kept at a very low value of 200 ml/h. The nanofluid, when separately characterized, demonstrated good lubrication and heat dissipation capability in reference with soluble oil, which is a commonly used cutting fluid for grinding. The superior tribological characteristics of hBN nanofluid were more pronounced at a high sliding speed of 1 m/s, as observed during a ball-on-disc test. However, the beneficial effect of using hBN nanofluid could be extracted more efficiently only in aggressive grinding condition. A clear drop in specific energy, favourable values of residual stress indicate the same. Prevalence of low grinding zone temperature was reflected through low specific energy values and finer but complex chip micromorphology. Overall the aqueous hBN nanofluid was proven to be a high performing grinding fluid suitable for SQCL application and WC-Co cermet grinding.