Investigation of Ceramic and Hardmetal Coatings in an Oscillating Sliding Wear Test

The present study was carried out within the scope of a project oriented toward the evaluation of applicability of different materials as thermally sprayed coatings for gear flank protection. Investigations were made on APS deposited oxide coatings, such as Cr₂O₃ and Magnéli phases of different systems, as well as on hardmetal coatings based on WC, Cr₃C₂ and TiC deposited by HVOF. All coating microstructures were investigated by optical microscopy, with selected samples studied additionally by SEM. Phase composition, hardness, Young’s modulus and fracture toughness were other basic coating properties studied. An oscillating sliding wear test was used as the main tool for preliminary evaluation before more laborious testing. The wear resistance in this test was investigated against 100Cr6 for all materials as well as against sintered silicon nitride and sintered WC-Co for oxide and hardmetal coatings, respectively. Hardmetal coatings based on WC and TiC showed the best results and were selected for further testing.