Characterisation of titanium based composite deposited by air plasma sprayed method on Aluminium substrate

Asma Salman

Abstract


Plasma spraying is most commonly used to produce thick coatings over a wide range of substrates. Thick coatings play an important role in improving the wear and corrosion resistance of a component. In this study, titanium based in-situ composite powder was produced by high energy mechanical milling using Al and TiO2 powders. The composite powder was then subjected to a self-propagating combustion reaction to produce feedstock for air plasma spraying. Very fine particles within the feedstock were treated using an organic binder to improve the overall flowabilty of the feedstock powder. The feedstock was then sprayed by air plasma spraying on an aluminum substrate. A thick composite coating was successfully deposited on an aluminum substrate. Composite coating was found continuous and uniform over the Al substrate. However, it showed poor adhesion with the substrate Composite coating showed porosities and micro-cracks. Microstructure of the coating revealed presence of three phases, alumina particle, metallic phase Ti(Al,O) and a ceramics phase (Al rich Ti-Al oxide). A longitudinal deformation was observed in case of aluminium particles compared with feedstock powder used for spraying.


Keywords


: Feedstock powder, Self-propagating combustion reaction, Mechanical milling, Air Plasma spraying



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