Proceedings of the Twelfth European Conference on Chemical Vapour Deposition

J. Phys. IV France 09 (1999) Pr8-987-Pr8-994
DOI: 10.1051/jp4:19998123

AlNi coatings on the internal surfaces of tubes

C. Labatut¹, C. Metz², G. Wahl², P. Bianchi³, M. Innocenti⁴ and J.-P. Hirvonen<sup>5

1</sup>  5 rue de la Pierre Bleue, 34160 Castries, France, and Joint Research Centre, Institute for Advanced Materials, TP202, 21020 Ispra (VA), Italy
²  Institut für Oberflächentechnik, Technische Universität Braunschweig, Bienroder Weg 53, 38108 Braunschweig, Germany
³  ENEL, via Rubattino 54, 20134 Milano, Italy
⁴  Nuovo Pignone, via F. Matteucci 2, 50127 Firenze, ltaly
⁵  JRC Petten, Institute for Advanced Materials, 1755 ZG Petten, The Netherlands

Abstract
The oxidation resistance of nickel based superalloys used for high temperature components in gas turbine can be increased by the formation of high temperature intermetallic NiAl compounds. In this study the internal surfaces of Inconel tubes, with an internal diameter of 1 mm and a total length of 280 mm were aluminised by means of a CVD process using AlCl₃ and Al as precursors. Subsequently, the aluminised samples were given a heat treatment under vacuum. Afterwards, the thickness and the composition homogeneity of the resulting NiAl layers before and after heat treatment were examined by electro-optical techniques that included optical and scanning electron microscopes and EDS X-ray microanalysis. The homogeneity of the resulted coatings was correlated to the deposition temperature and deposition time.

© EDP Sciences 1999