The boriding process in CoCrMo alloy: Fracture toughness in cobalt boride coatings

Based on the indentation results, the KC values of the cobalt boride coatings were estimated using the universal crack equation, which is applicable independent of the cracking mode. The results indicated that the CoB and Co2B coatings exhibited two types of cracking modes (intermediate and radial-median, respectively), and that the fracture toughness of the Co2B coating was ten-fold greater than that of the CoB coating.