Effect of annealing in low-temperature plasma on the performance properties of the nitrided layer+Ti(N,C,O) type composite layers
Paweł Mańkowski, Kerzy Robert Sobieski, Tadeusz Wierzchoń Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa
Annals 4 No. 9, 2004 pages 68-73
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abstract The paper presents a new method of modifying the chemical composition and properties of the composite layers of the nitrided layer+Ti(N,C,O) type. The method consists of annealing the layer in a glow discharge generated by hydrogen-nitrogen plasma. The layers were produced in a universal apparatus designed for glow discharge treatments (Fig. 1), using a gaseous mixture composed of the tetraisopropoxytitanium vapours, hydrogen and nitrogen. The process was conducted at a temperature of 500°C. The final annealing does not affect the thickness of the Ti(N,C,O) but it influences on the chemical composition of the coating. It increases the nitrogen content in the near-surface titanium oxycarbonitride layer, whereas the oxygen and carbon contents decrease, this also reduces the roughness of the surface (Figs 2 and 3), and improves the performance properties, such as the frictional wear resistance (Fig. 4). The action of hydrogen is responsible for the changes in the chemical composition especially in the decreasing the oxygen and carbon content. The scheme of the formation of the composite layer nitrided+ Ti(N,C,O) type subjected to the final annealing in the hydrogen and nitrogen atmosphere is proposed (Fig. 6). Key words: PACVD process, glow discharge, composite layers, structure, properties