Ceramic coating technology

Abstract

Modern technology calls for systems performing satisfactorily under extreme and often adverse operating conditions; hence it has become a technical and economic necessity to protect structural materials from the hostile environment. Thus ceramic coating technology (CCT) has found widespread applications in many diverse industries for the protection of structural materials. Ceramic coatings are used to minimise effects such as high temperature degradation, corrosion, erosion and wear. Two techniques, viz. thermal spray and chemical vapour deposition, are well-developed and commercially established for preparing coatings of almost all ceramic materials. Each process has its own advantages and disadvantages and the choice of any particular method depends on the application, economics etc. CCT is both technically and commercially well-established abroad. Commercial equipment suitable for general application in coating shops as well as custom-engineered ones to suit specific requirements are readily available. Raw materials such as powders, wires, rods, gases, chemicals etc. are readily available and are moderately priced. R & D is continuously in progress adding new materials, techniques and applications every year. In India, the full potential of the technology has not been tapped as yet. A few governmental organisations such as BARC, BHEL, DMRL, HAL, Air India etc., have exploited the application potential of the technology, while the private industry has begun to adopt the technology only recently. Such a situation is due to a variety of reasons including limited awareness of these new techniques amongst our user industries, nonavailability of raw materials and equipment indigenously etc.