Various potential surface treated materials paired with multiple cathodic arc plasma (CAP) deposition TiN coating specimens, to be used for screws and rollers, were tested on an SRV wear machine (Optimol, Germany) under reciprocating wear conditions. The processing parameters of the TiN coatings, including bias voltage, arc current and partial pressure of N2, were optimized before wear testing. The polishing pre-treatment of the substrate yielded the highest wear resistance. The indentation test showed that adhesive strength decreased with increasing coating thickness. If the coating was too thin, it was easily worn through. The optimum coating thickness was 3 μm. It was concluded that PVD coated TiN paired with surface treated specimens possesses less wear resistance under HD150 and base oil lubrication. Under water-based cutting fluid, the self-mated TiN and TiN-surface treated specimen pairs showed no measurable wear, only surface polishing on the TiN surface. Both are potential sliding pairs for TiN coating in machine element applications. The wear mechanisms of TiN include local flaking of the coating layer at the edge of the wear scar, surface polishing and surface pitting under oillubricated wear. The wear mechanisms under dry wear result in a residual TiN unworn layer with or without a transferred layer, and the exposed substrate region covered with a transferred layer. Suitable sliding pairs are self-mated TiN and TiN-surface treated specimens under cutting fluid lubrication, and carburized specimens paired with TiN coated specimens under base oil lubrication.
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