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Open AccessArticle

Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina

SAR Consulting, Rua Maria Vieira da Silva, Lote 2, 3B, 8600-780 Lagos, Portugal
Coatings 2020, 10(2), 158;
Received: 21 December 2019 / Revised: 5 February 2020 / Accepted: 5 February 2020 / Published: 9 February 2020
(This article belongs to the Special Issue Surface Engineering for Friction and Wear Reduction)
In the present study, the influence of experimental variables on the growth characteristics and texture development in chemically vapour deposited α-Al2O3 coatings was investigated. The emphasis was on the effects of H2S. The α-Al2O3 layers were deposited from the AlCl3-H2-CO2-HCl-H2S precursor system onto intermediate Ti(C,N) layers. The substrate was cemented carbide. The coatings were characterized with respect to microstructure and texture using X-ray diffraction, scanning electron microscopy and electron back-scattering diffraction. The observations were unpredictable, suggesting that in addition to the growth rate, H2S strongly affected the texture of the α-Al2O3 coatings. The uncatalyzed α-Al2O3 coatings (H2S = 0) developed (11 2 ¯ 0) texture. With the increment of H2S concentration the texture changed from (11 2 ¯ 0) texture through (10 1 ¯ 0), (10 1 ¯ 2) and (10 1 ¯ 4) textures to (0001) texture. Growth regimes for (11 2 ¯ 0), (10 1 ¯ 0), (10 1 ¯ 2), (10 1 ¯ 4) and (0001) textures were depicted as a function of the H2S/CO2 ratio. Examples of grain-boundary and microstructural manipulation of CVD α-Al2O3 layers by applying texture control were presented. View Full-Text
Keywords: α-Al2O3; chemical vapour deposition; CVD; texture α-Al2O3; chemical vapour deposition; CVD; texture
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Ruppi, S. Influence of Process Conditions on the Growth and Texture of CVD Alpha-Alumina. Coatings 2020, 10, 158.

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