Structural and Mechanical Properties of (AlxCr1-x)2+yO3-y Coatings Grown by Reactive Cathodic Arc Evaporation in As-deposited and Annealed States
2013 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 61, no 13, 4811-4822 p.Article in journal (Refereed) Published
Coatings of (AlxCr1-x)2+yO3-y with 0.51≤x≤0.84 and 0.1≤y≤0.5 were deposited on hard cemented carbides substrates in an industrial cathodic arc evaporation system from powder-metallurgy prepared Cr/Al targets in pure O2 and O2+N2 atmospheres. The substrate temperature and bias in all the deposition runs were 575 °C and -120 V, respectively. The composition of the coatings measured by energy dispersive x-ray spectroscopy and elastic recoil detection analysis was the same as that of the targets. Microstructure analyses performed by symmetrical X-ray diffraction and transmission electron microscopy showed that corundum, cubic or mixed-phase coatings formed depending on the Cr/Al ratio of the coatings and O2 flow per activetarget during deposition. The corundum phase was promoted by high Cr content and high O2 flow per target, while the cubic phase was mostly observed for high Al content and low O2 flow per active target. In situ annealing of the cubic coatings resulted in phase transformation from cubic to corundum completed in the temperature range of 900-1100 °C, while corundum coatings retained their structure in the same range of annealing temperatures. Nanoindentation hardness of the coatings with Cr/Al ratio < 0.4 was 26-28 GPa, regardless of the structure. Increasing the Cr content of the coatings resulted in increased hardness of 28-30 GPa for corundum coatings. Wear resistance testing in a turning operation showed that coatings of Al-Cr-O have improved resistance to crater wear at the cost of flank wear compared to TiAlN coatings.
Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 61, no 13, 4811-4822 p.
Physical vapor deposition (PVD); Ternary alloys; Alumina (α-Al2O3); Solid solution; Al-Cr-O alloys
IdentifiersURN: urn:nbn:se:liu:diva-87666DOI: 10.1016/j.actamat.2013.05.002ISI: 000321601400011OAI: oai:DiVA.org:liu-87666DiVA: diva2:592198