TY - THES

T1 - Synthesis and Characterisation of AlCrMoN Coatings

AU - Holly, Sylvia

N1 - embargoed until null

PY - 2006

Y1 - 2006

N2 - The elements V, Mo, W and Ti show the ability to form lubricious Magneli phase oxides. To combine these self-lubricious properties with wear resistance, the aim of this thesis was to integrate Mo into hard wear-resistant AlCrN coatings. The coatings were synthesised by an arc evaporation process. The composition was varied by the substitution of Cr by Mo, where the Al content in the target was held constant at 70 at%. For characterisation, tribological tests were conducted at room temperature, 500°C and 700°C. Furthermore, X-ray diffraction patterns were recorded, adhesion, hardness and roughness were measured, as well as Raman spectroscopy and scanning electron microscopy analysis were carried out. The friction coefficients at room temperature were rather low, but they increased with augmenting temperatures so that failure of the coating occurred at the latest at 700°C. Therefore, it can be assumed that the formed molybdenum oxides were evaporated within short time because of their high volatility. Raman spectroscopy confirmed the lack of the sufficient presence of lubricious oxides. Although it was possible to synthesize coatings of excellent wear resistance by alloying of Mo to AlCrN, no self-lubricious effects could be realized.

AB - The elements V, Mo, W and Ti show the ability to form lubricious Magneli phase oxides. To combine these self-lubricious properties with wear resistance, the aim of this thesis was to integrate Mo into hard wear-resistant AlCrN coatings. The coatings were synthesised by an arc evaporation process. The composition was varied by the substitution of Cr by Mo, where the Al content in the target was held constant at 70 at%. For characterisation, tribological tests were conducted at room temperature, 500°C and 700°C. Furthermore, X-ray diffraction patterns were recorded, adhesion, hardness and roughness were measured, as well as Raman spectroscopy and scanning electron microscopy analysis were carried out. The friction coefficients at room temperature were rather low, but they increased with augmenting temperatures so that failure of the coating occurred at the latest at 700°C. Therefore, it can be assumed that the formed molybdenum oxides were evaporated within short time because of their high volatility. Raman spectroscopy confirmed the lack of the sufficient presence of lubricious oxides. Although it was possible to synthesize coatings of excellent wear resistance by alloying of Mo to AlCrN, no self-lubricious effects could be realized.

KW - Hard coatings Arc evaporation AlCrMoN Magneli phases

KW - Hartstoffschichten Lichtbogenverdampfung AlCrMoN Magneli Phasen

M3 - Diploma Thesis

ER -