Magnetic moment studies on nickel coated titanium powders

摘要

Titanium aluminide intermetallics are gaining greater importance due to their low density, high melting temperature, good high temperature properties and oxidation resistance. Their brittle behaviour at low temperatures has resulted in several investigations aimed at improving their ductility. This can be improved either by suitably alloying or by micro-structure control [1-5] and in some cases by both. In general, microstructural refinements developed through processing lead to improvements in both strength and ductility [6]. Thus, processing techniques that increase the range of attainable micro-structures are fundamental to the development of new engineered materials. These alloys cannot be produced by the traditional metallurgical processes, because of the restricted range of the atomic percentage of the alloying elements. Conventional powder metallurgical (P/M) techniques can be used for preparing these alloys, with an additional step involving coating on the elemental powders. There are several coating methods available like vapour phase deposition techniques, spray deposition, electroplating, and electroless coating. Each of these has its advantages and disadvantages. Vapour phase deposition methods can be used for coating tow-based fibres such as carbon fibres [7]. Electroplating methods can also be used for carbon fibres, for which the substrate should be a conducting material. Coating a powder with a particular element is easier by the electroless coating method because it gives a uniform coating on the substrate.