The influence of environmental dust in humid ambient air on laser surface treated carbide cutting tools

CO₂ laser surface treatment of cemented carbide cutting tool is considered and the resulting surface wetting state and texture characteristics are examined using analytical tools. The morphological and metallurgical changes in the CO₂ laser treated layer are assessed, and microhardness and fracture toughness of the resulting surface are analysed. The influence of mud formed from the environmental dust particles in humid ambient air on the CO₂ laser treated surface is investigated and the tangential force required for removing the dried mud from the cemented carbide cutting tool surface is measured. It is found that the CO₂ laser treatment slightly increases the microhardness and lowers the fracture toughness of the cemented carbide cutting tool surface. The CO₂ laser treated surface has texture characteristic consisting of hierarchically distributed micro/nanopillars. The CO₂ laser treatment reduces the surface free energy, in which case the wetting state of the cemented carbide cutting tool surface changes from hydrophilic to hydrophobic after the laser treatment process. The water condensation on to the dust particles gives rise to mud formation on the substrate surface in humid air ambient, which enhances the dust particles adhesion onto the surface upon drying. The tangential force required to remove the dried mud from the untreated cemented carbide cutting tool surface is almost twice of the CO₂ laser treated surface; consequently, the laser treatment significantly lowers the dried mud adhesion on the surface.