Laser surface texturing of granite

Presence of contaminants on surfaces becomes a significant problem both in industry and at home. Small particles or bacteria adhered to surfaces of domestic kitchens are not easily removed by regular cleaning procedures. The effect of substratum wettability upon contaminants adhesion has been known for a long time. The phenomenon of surface cleaning is closely related to morphology, and chemistry of surfaces. These characteristics can be modified by subjecting materials to surface treatments. One of the most promising techniques aiming to modify surface features is the laser texturing. In such a way, it is possible to achieve the surface properties leading to the desired wettability in an accurate manner, and with minor contamination. In this work, the wetting features of Zimbabwe black granite, a middle-to-fine-grained natural stone commonly employed as countertops in kitchens and bathrooms, are modified by laser surface texturing. The main aim is to increase its hydrophobic degree so as to reduce the attachment of contaminants on the surface. For such purpose, two laser sources (λ = 1064 and 532 nm) were employed. The influence of different laser processing parameters on surface characteristics (wettability, roughness, and chemistry) of granite was statistically assessed. The morphology resulted from the laser surface texturing was found to be the principal phenomenon governing the wettability modifications, as the chemical composition remained virtually unaltered after treatment.