Laboratory scale development of coating for improving characteristics of candidate materials for fusion reactor

Application of coatings of refractory low atomic number materials on to different components of Tokamak type controlled thermonuclear reactor are expected to provide a degree of design flexibility. The project envisages to deal with the challenging problem on laboratory scale. Coatings investigated include carbon, beryllium, boron, titanium carbide and alumina and substrates chosen were 304, 316 stainless steels, monel-400, molybdenum, copper, graphite, etc. For their deposition, different techniques (e.g., evaporation, sputtering and their different variants) were tried, appropriate ones chosen and their parameters optimized. The coating composition was analyzed using X-ray diffraction (XRD), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Rutherford backscattering analysis (RBS) and secondary ions mass spectroscopy (SIMS). Surface morphology was studied using scanning electron microscopy (SEM). Sebastian coating adherence tester was used for adhesion measurement and Wilson's Tukon microhardness tester for their microhardness measurement. The coatings were subjected to pulses from YAG laser to evaluate their thermal cycling behavior. Deuterium ion bombardment (energy: 20 to 120 KeV; doses: 10(19) 9.3x10(20) ions sq cm behavior was also studied. In general, adherent and hard coatings capable of withstanding thermal cycling could be deposited. Out of the coatings studied, titanium carbide shows best results.