Mechanical and Tribological Properties Evolution of [Si3N4/Al2O3]n Multilayer Coatings

Multilayer coatings [Si3N4/Al2O3]n have generated great interest due to their intriguing properties which have made them a potential candidate to be implemented in different processes within the food and pharmaceutical industries. Unfortunately, this multilayer system based on [Si3N4/Al2O3]n does not have strong tribological studies that could express in an emphatic way its own tribological characteristics. For this reason, the aim of this research consisted of a detailed study of the evolution of the mechanical and tribological properties of the [Si3N4/Al2O3]n coatings as a function of the bilayer number n=1, 10, 30 and 70, with special emphasis on the tribological analysis in a dry and lubricated environment. It was determined that the mechanical properties such as the hardness and the elastic modulus increased by 29% and 6.3%, while the friction coefficient in a dry and lubricated environment decreased by 33% and 81.8%, respectively, when increasing the bilayers from n=1 to n=70. Thus, the present study determined that the coating [Si3N4/Al2O3]70 presented ideal properties that make it a promising candidate to be implemented as a protective coating on processing devices within the food and pharmaceutical industry.