SYNTHESIS- AND CHARACTERIZATION OF COMPOSITE EL COATINGS FOR RADAR APPLICATIONS

Abstract

Amongst the various techniques used to prepare amorphous solids, electroless deposition is an important method, established over the years. The process of electroless deposition is one of the most elegant methods available for the production of coatings. The technique involves the autocatalytic reduction, at the substrate/solution interface, of cations by electrons released from suitable chemical agents and, a significant degree of elemental release from these agents allowing co-deposition with the reduced metal. The ability to co-deposit particulate matter in electrolessly deposited matrices has led to a new generation of composite coatings. These offer a challenge to the platter and designer to incorporate deposits having unique physical and/or chemical properties. Particulate matter that can be co deposited ranges from dielectrics and metals to compounds and metal alloys_ and combinations of these. Properties of the composite coatings are particularly dependent upon the concentration, particle size distribution, and the nature and morphology of the particulate matter, as well as the electroless-plating bath employed. When electroless coating is done on a substrate with ferrite, which is used as radar absorbing material (RAM) as a particulate matter, the coating absorbs microwave energy, which makes its detection by radar difficult. In the present study, synthesis. and characterization of a new electroless Ni-P based composite coatings on substrate material viz. commercial aluminum have been carried out. The ferrite powder is synthesized by a recently developed citrate method and XRD, SEM, DSC, etc. were used to analyze and examine the powder. Ferrite was suspended in with coating solution containing reducing agent, Ni- source, inhibitors and ..........