Hardness evolution of Al-Cr-N coatings under thermal load
2008 (English)In: Journal of Materials Research, ISSN 0884-2914, Vol. 23, no 11, 2880-2885 p.Article in journal (Refereed) Published
Microstructure and hardness evolution of arc-evaporated single-phase Cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, We Can Conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures T-a <= 900 degrees C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 +/- 1.1 GPa to 29.4 +/- 0.9 GPa with T-a increasing to 900 degrees C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at T-a >= 700 degrees C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 +/- 1.3 GPa to 31.6 +/- 1.4 GPa with T-a = 725 degrees C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 +/- 1.0 GPa with T-a = 900 degrees C.
Place, publisher, year, edition, pages
2008. Vol. 23, no 11, 2880-2885 p.
IdentifiersURN: urn:nbn:se:liu:diva-16136DOI: 10.1557/JMR.2008.0366OAI: oai:DiVA.org:liu-16136DiVA: diva2:133223