Investigation of tribo-thermal properties of inter-mixed AYSZ nanoceramic composite/SAE20W40 nanolubricant

Recently, inter-mixed alumina, zirconia, and yttria-based nanoceramic composites have been widely used for medical implants and thermal barrier coatings, including tribology applications, due to their high tribo-thermal, chemical, and structural phase stability. The present investigation deals with nanolubricant with hollow spherical inter-mixed alumina yttria-stabilized zirconia (AYSZ) nanoceramic composite as an additive. The AYSZ/SAE20W40 nanolubricant was prepared at two different mass percentages (0.22 and 0.33 mass% of NPs) using the ball milling method. The hollow spherical AYSZ nanocomposite particles were broken into nanopot pieces due to impact and frictional forces between the ceramic balls during the attrition process. The broken pot-like AYSZ nanopieces in nanolubricant showed good dispersive stability due to the increased surface area. The prepared AYSZ/SAE20W40 nanolubricant samples were investigated for their tribological properties, such as frictional coefficient, frictional force, wear, and specimen mass loss, including thermal conductivity. The results for nanolubricant with 0.33 mass% of AYSZ samples showed better wear reduction (106.10%) and thermal conductivity (1.38%) than 0.22 mass% and SAE20W40 engine oil. Hence, the AYSZ nanoceramic was proven as a nanoadditive for lubricant tribo-thermal application by reducing the boundary lubrication wear.