Deposition and Analysis of Al-Rich c-AlxTi1-xN Coating with Preferred Orientation

作者：Paseuth Anongsack^*; Yamagata Kazuo; Miura Akira; Higuchi Mikio; Tadanaga Kiyoharu

来源：Journal of the American Ceramic Society, 2017, 100(1): 343-353.

DOI：10.1111/jace.14549

Metastable c-AlxT1-xN is an important and well-established hard coating in the tool industry. To improve the mechanical and thermal properties, Al-rich c-AlxTi1-xN coatings with controllable preferred crystal orientations were fabricated via low-pressure chemical vapor deposition (LP-CVD) in an industrial plant, using an AlCl3-TiCl4-NH3-Ar-H-2 precursor system. The c-AlxTi1-xN coatings with (100)- and (111)-preferred orientations and average x values of 0.82 and 0.73, respectively, comprised c-Al(Ti)N/c-Ti(Al)N nanolamellae with average compositions of c-Al0.9Ti0.1N/c-Al0.6Ti0.4N and c-Al0.80Ti0.20N/c-Al0.50Ti0.50N; the average lamellar periods were 7.7 and 4.5 nm, respectively. High-resolution transmission electron microscopy indicated that the c-Al(Ti)N/c-Ti(Al)N nanolamellae were modulated along the < 100 > direction, implying coherent spinodal decomposition of c-AlxTi1-xN in the as-deposited state. The hardness of the c-AlxTi1-xN coatings varied from 33 to 36 GPa, depending on the (100)- or (111)-preferred orientation. Residual stress measurements in the as-deposited state showed tensile stress values of 1.8 and 4.6 GPa for the (100)- and (111)-oriented c-AlxT1-xN coatings, respectively. This stress may be generated by the difference in the thermal expansion coefficient of the c-AlxT1-xN coating and the carbide substrate and by coherency stress in the c-Al(Ti)N/c-Ti(Al)N nanolamellae. In situ high-temperature X-Ray diffraction results revealed high thermal stability up to 1000 degrees C.

• 出版日期2017-1