Synergistic effect on the tribological properties of tool steel through the use of laser surface texturing channels and nanoparticles

Abstract

Many studies have been focused on the positive effect of laser surface texturing (LST) for tribological performance of several metal mechanic tools and machine elements. Different geometries have been studied and benefits have been found in the two main tribo characteristics: coefficient of friction (COF) and wear. The most analyzed geometry, because of its ease of manufacturing, is the circle. Not enough has been studied respective of the effect of the orientation of micro channels and nanoparticles in lubricants together. This work shows the results obtained by adding the synergistic efforts of the use of laser surface texturing channels in two orientations (vertical (V) or horizontal (H)) and the use of TiO2 nanoparticles dispersed at 0.05 wt% within a poly alpha olefin (PAO4). A T-05 conformal contact block-on-ring equipment was used for the tribological tests (COF and wear values) according to ASTM G77 standard with continuous revolutions ensuring constant lubrication. The output parameter of surface finish was measured using a 3D Alicona Edgemaster surface analyzer. Reductions of up to 76% and 89% were reached for COF and wear respectively for laser surface textured test blocks. The addition of nanoparticles was able to reduce also COF by 68% and 97% in wear; also improvements in roughness was founded when micro channels and nanoparticles (NP) was used together in values up to 50%. With this study the synergistic effect of channel texturing (including orientation of the channels) and the use of nanoparticles on lubricants in conformal contact processes such as for deep drawing processes was demonstrated.