Fretting wear properties of HVOF-sprayed CoMoCrSi coatings with different spraying parameters

CoMoCrSi superalloy coatings were prepared on Mar-M247 Ni-based superalloy by high velocity oxygen fuel (HVOF) under various spraying parameters. Dense coatings with porosity < 0.8% were prepared, and the fretting wear properties of the coatings was investigated. The coatings showed good adaptability to the spraying parameters. As the temperature increased from R.T. to 400 degrees C, the friction coefficient of the coating decreased from 0.8 to 0.6, and the wear morphology gradually changed from pits to bulges. A large amount of material transfer occurred, and the main wear mechanisms at R.T. were abrasive wear and delamination; adhesive wear appeared slowly at elevated temperatures. The coating exhibited better wear resistance than the substrate during the experiments.