The aim of the study was to investigate effect of Ti/TiB₂ composite composition and manufacturing technology parameters on the tribological behaviour of AlCrN coating-composite system. The AlCrN coating was deposited by PVD (Physical Vapour Deposition) method. The composites were manufactured by spark plasma sintering (SPS) from three variants of powders mixtures: Ti with TiB₂, Ti6Al4V with TiB₂ as well as Ti with B, using (five) different sintering temperatures. For each of the developed coating-composite systems, the wear resistance was evaluated using ball-on-disc SRV tester, at six temperatures (from room temperature up to 900 °C). The results confirmed that high-temperature wear resistance of the coating–substrate combination depends on Ti/TiB₂ composite composition and manufacturing technology parameters. In the case of uncoated composite, two processes manage the wear at high temperatures: cracking propagation and surface oxidation. The presence of AlCrN coating on the composite surface protects the surface against deep cracking and surface oxidation. The composites of Group I, sintered at 1250 °C from a mixture of pure Ti and TiB₂ (50/50 wt.% ratio) as well as Group III, sintered at 1350 °C from a mixture of pure Ti and B allow the achievement of a satisfactory surface quality, a high adhesion of the PVD coating and moderate wear at high temperatures. However, the composite made of pure Ti and B seems to be a better solution for temperatures exceeding 600 °C.

An alumina-toughened zirconia (ATZ) material, fabricated using a procedure consisting of the common sintering of two different zirconia powders, was tested using the ball-on-disc method in a temperature range between room temperature and 500 °C. Corundum balls were used as a counterpart. The ATZ composite behaviour during tests was compared with that of commonly used α-alumina and tetragonal zirconia sintered samples. At temperatures over 350 °C, a drastic decrease in the wear rate of the material was detected. SEM analyses proved that, in such conditions, nearly the whole surface of the sliding material was covered with a layer of deformed submicrometric grains, which limited contact with the part of material that was not deformed. The mentioned layer was relatively strongly connected with the material, increased its resistance, and decreased its coefficient of friction. As a reference, commonly used materials, namely commercial alumina and tetragonal zirconia, were tested. The wear parameters of the composite were significantly better than those registered for the materials prepared of commercial powders.

The aim of this work is to study the effect of solid lubricants on the wear of various types of coatings deposited by the physical vapour deposition (PVD) method on TiB₂/Ti composites produced through spark plasma sintering (SPS). The following coatings are investigated: TiN-TiCrN-AlCrN-AlCrTiN/Si₃N₄, TiN-TiCrN-AlCrN-AlCrTiN/Si₃N₄₋ AlCrTiSiN+grad ON, TiN-TiCrN-AlCrN-AlTiCrN, and, as a reference, a commercially available AlCrN-based coating. Hexagonal boron nitride and graphite are used as solid lubricants. The wear tests are performed by means of ball-on-disc SRV friction and wear tester employing reciprocating motion of the Si₃N₄ ball, sliding against a coated disc. Changes in the worn out surface are analysed using green light interferometry. From the studies it follows that an external application of both solid lubricants to an uncoated TiB₂/Ti composite - an Si₃N₄ ceramic ball tribo-pair - does not improve its wear characteristic, whereas the use of the same solid lubricants for a coated TiB₂/Ti composite can improve the wear behaviour, depending on the material and structure of a coating.

In this paper, the achieved state-of-the-art understanding regarding the wear behaviour of various PVD (physical vapour deposition) coatings deposited on TiB₂/Ti composites produced by SPS (spark plasma sintering) is presented. The objective of this paper is to investigate the wear behaviour of various PVD coatings deposited on TiB₂/Ti composites manufactured by SPS, when lubricated with hexagonal boron nitride (hBN) as an external solid lubricant in the range from room temperature up to 900 °C in friction contacts under extreme pressure and with oscillation relative motion. Four multicomponent and multilayer coatings were investigated based on AlCrN and TiCrN coatings with TiCrN-AlCrN/AlCrTiN/Si₃N₄ interlayers and various external layers (AlCrN, Si₃N₄, AlCrTiSiN, and AlCrTiSiN gradient with increasing oxygen gradient replacing nitrogen). The wear tests were performed by means of a ball-on-disc SRV friction and wear tester using reciprocating motion of the Si₃N₄ ball sliding against a coated disc from room temperature up to 900 °C. The best protection against wear and oxidation at higher temperatures (even up to 900 °C) was achieved for coatings with AlCrN and AlTiCrN external layers, and hBN lubricant was used simultaneously.