Hydrothermal synthesis of barium titanate was done by both microwave heating and conventional heating. The synthesis process was evaluated by examining samples at different processing times by X-ray diffraction. For samples produced by both heating methods, the metastable cubic phase crystallized first and gradually transformed to a tetragonal phase. Microwave synthesis showed advantages of shortened crystallization time, increased c/a ratio, and upon sintering led to a larger degree of increased c/a ratio. Elemental analysis showed a smaller Ti/Ba ratio and larger relative amount of Cl- ion in the microwave-treated sample than those in a conventionally treated sample. Sintering at 850 °C for both samples resulted in the samples exhibiting a clear transition temperature of around 125 °C as measured by DSC.

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The thermal decomposition of NF 3 by various oxides was investigated using gas chromatography, BET surface areas, and X-ray powder diffraction. The decomposition of NF 3 using alumina can occur at temperatures as low as 100°C, with steady complete conversion for almost 4 h at 400°C. The reaction is shown to be stoichiometric. Using Na-doped alumina, conversion of NF 3 dropped off faster than conversion with the undoped alumina. Similarly, calcium oxide did not react with the NF 3 as completely or last as long as the alumina did; even at 400°C the conversion of NF 3 was only briefly greater than 90%. HX zeolite was also reacted with NF 3 , with higher and more consistent conversion than occurred with calcium oxide and Na-doped alumina, but did not perform as well as the alumina. Over 98% conversion was maintained at 400°C for more than 1 h. In all cases, nitrogen oxides and the corresponding metal fluorides were the only major products from the reactions. The XRD patterns confirm the presence of metal fluorides for all of the materials investigated. On the basis of these investigations, it has been concluded that of all the oxides studied, alumina is the best oxide getter for NF 3 .