Tribological Properties of Coatings Applied on Near-Nano and Nanostructured WC-Co Hardmetals by Using Plasma-Assisted Chemical Vapour Deposition Technique

Abstract

Samples of nanostructured hardmetals were sintered as a substrate material by applying two different powder metallurgy processes. The starting powders had an average grain size from 95 nm to 150 nm. The plasma-assisted chemical vapour deposition technique was used for the deposition of coatings and two coating systems, i.e. the 2 µm titanium nitride and 3.8 µm titanium carbon nitride were produced. Scratch tests were conducted with an increasing load ranging from 5 to 200 N. Critical normal loads of coating delamination during the scratch tests were registered. The sliding wear resistance was investigated with a ball-on-disc test. The ball-on-disc test showed that the porosity of the sintered product had the highest impact on the wear volume loss. Nanostructured hardmetals showed a great potential for application of plasma-assisted chemical Vapour deposition.

Effect of Induction Heating on Surface Properties of Hot-Pressed Ceramics Based on Nanopowders Si3N4 and TiN

“…Without additional grinding, the fracture toughness of ceramics composed of Al2O3-AlN-TiN increases with an increasing load up to 500 N (Figure 3b). This contrasts with the dependence observed in [46] for hard metals. This difference can be explained by the quenching effect on crack propagation within the pores of the surface layer.…”

“…The occurrence of the highest hardness at 100 N may be attributed to the unique nanostructure features of ceramics based on plasma chemical powders. However, as the load continues to increase, the material undergoes destruction, leading to a decrease in hardness, similar to what has been observed in [46,47]. The hardness of hot-pressed ceramic material composed of Al2O3-AlN-TiN (Table 1, sample 8) increases with an increasing load up to 100 N but then decreases as the load further increases to 500 N. This observed dependence contradicts the nonlinear relationship between hardness and loads reported in [46,47], where the highest hardness at 100 N is not present.…”

“…The occurrence of the highest hardness at 100 N may be attributed to the unique nanostructure features of ceramics based on plasma chemical powders. However, as the load continues to increase, the material undergoes destruction, leading to a decrease in hardness, similar to what has been observed in [46,47].…”

“…The hardness of hot-pressed ceramic material composed of Al 2 O 3 -AlN-TiN (Table 1, sample 8) increases with an increasing load up to 100 N but then decreases as the load further increases to 500 N. This observed dependence contradicts the nonlinear relationship between hardness and loads reported in [46,47], where the highest hardness at 100 N is not present. The occurrence of the highest hardness at 100 N may be attributed to the unique nanostructure features of ceramics based on plasma chemical powders.…”

Corrosion Behavior of Amorphous Sol–Gel TiO2–ZrO2 Nano Thickness Film on Stainless Steel

“…Ceramic coatings can be deposited on the substrate by several various techniques that have been developed for this purpose. They include physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition, thermal spraying, plasma spraying and solgel processes, such as spin-, dip-and spray-coating [9,10,13,14]. Among these techniques, sol-gel techniques are often preferred for several reasons: they are simple, low temperature (usually 200 to 600 • C) techniques, which avoid possible decomposition problems; can provide high-purity, high-quality and stoichiometric coatings; the adjustment of the film thickness can be done easily; some of them, like the dip-coating method, are suitable for coatings of complex-shaped substrates, etc.…”