OPTIMIZATION OF LOAD AND HBN CONTENT FOR IMPROVING TRIBOLOGICAL PERFORMANCE OF A SI3N4-HBN CERAMIC COMPOSITE USING TAGUCHI-GREY RELATIONAL ANALYSIS

Silicon nitride (Si3N4) is common in various industrial applications and proven its applicability with its high fracture toughness, strength and wear properties. The material has a proven capability in the biomedical field in the context of orthopedic applications. This paper reports the experimental and Taguchi based grey relational analysis for the tribological behavior of Si3N4-hBN ceramic composite sliding against steel (ASTM 316L) in the dry condition. The wear tests were conducted with 0, 4, 8, 12, and 16 % volume of hBN in Si3N4 at loading conditions in the range 5N < Load < 25N, with 5N increments using Pin-on-Disc (PoD) tribometer. A weighted grey relational grade is calculated for minimization of volumetric wear rate and coefficient of friction with aim of improving tribological performance of Si3N4-hBN ceramic composite applicable for various industrial and biomedical applications. Load and % volume of hBN addition are two factors considered for optimization. Analysis of variance (ANOVA) presented % vol of hBN is significant factor followed by load. In the Si3N4-hBN / steel contact pair, the main phenomenon of wear observed was an adhesive type of wear at both low load and at high load.