Sliding wear resistance of Fe-, Ni- and Co-based alloys for plasma deposition

Performance of Fe-, Ni- and Co-based alloys was evaluated in sliding wear and in the impact wear tests to simulate wear of valves and valve inserts in internal combustion engines. From the SEM investigations adhesive wear was confirmed by metal transfer between rubbing surfaces while surface deformation testify to abrasive wear. It was found that oxides formed on the surface prevented direct metal-to-metal contact and reduced the coefficient of friction thereby reducing wear. A comparison of wear resistances of Fe, Ni- and Co-based alloys used as hardfacings were given. It is also shown that Ni–Co alloys with Ni-alloy content between 40.4 and 64.3 have a considerable potential, they reveal above 2 times higher wear resistance than plasma-deposited cobalt alloy.