Stress evolution in CrN/Cr coating systems during thermal straining

Autor: Christian Mitterer, Klaus J. Martinschitz, Jozef Keckes, Rostislav Daniel
Rok vydání: 2008
Předmět:
Zdroj: Thin Solid Films. 516:1972-1976
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2007.10.106
Popis: CrN, Cr and CrN/Cr coatings were deposited at 350°C on monocrystalline Si(100) and polycrystalline austenitic stainless steel substrates by magnetron sputtering using Cr targets in Ar + N2 atmosphere. The stress evolution in the coating systems were characterized using X-ray diffraction and wafer curvature technique in the temperature range of 25–550°C. Both techniques revealed larger stresses in coatings deposited on the steel substrates. The heat treatment reduces the deposition point defect concentration, which is reflected in a decrease of intrinsic stresses in Cr and CrN coatings. Additionally, roughness of the Cr films decreases. The stresses in the individual sublayers of the CrN/Cr bilayer coatings indicate that the constraint imparted by the CrN layer on the buried Cr layer prevents a stress relaxation in Cr since no stress hysteresis is observed during heating and cooling. The intrinsic stresses of CrN are − 3.4 ⁎ 109Pa on the steel substrate and − 1.7 ⁎ 109Pa on the Si(100) substrate. For Cr intrinsic stresses of − 1.35 ⁎ 109Pa are obtained on steel and − 0.7 ⁎ 109Pa on Si(100). The intrinsic stresses of CrN in the CrN/Cr bilayer system remains at − 3.4 ⁎ 109Pa on the steel but increases to − 2.8 ⁎ 109Pa on the Si(100) substrate. As a result of the annealing cycle, a stress relaxation of approximately 1.3 ⁎ 109Pa is obtained for CrN on steel but 3.4 ⁎ 109Pa are relaxed for CrN in the CrN/Cr/steel system.
Databáze: OpenAIRE
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