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Short mullite fibers were fabricated by adapting the kneading–drying–calcination (KDC) process. The effect of foam forming on the formation of mullite fiber from kaolin via the KDC process, with the addition of a foaming agent, was examined. In the present study, doped sodium phosphates promoted the growth of mullite fiber and the formation of a glass matrix—effects that were ascribed to the P2O5 and Na2O components, respectively, of the sodium phosphates. In particular, the addition of sodium phosphates greatly reduced the treatment time that was required for dissolution of the glass matrix in hydrofluoric acid. The addition of 10 mass% of sodium dihydrogen phosphate and calcination at 1500°C for 10 h were the optimum conditions for a short treatment time and the formation of long fibers.

The kinetics of the solid-state reaction of strontium carbonate with anatase and rutile in air and carbon dioxide were studied by use of a thermobalance. The product was single-phase SrTiO3 in all cases. The relation between fraction reacted and time was fitted to the Jander equation and to the Carter equation for both anatase and rutile. For anatase the rate constant in carbon dioxide did not differ from that in air. The reaction rates for rutile in air and in carbon dioxide were ⅓ and ⅛ that for anatase, respectively. The In k vs 1/T relation for anatase gave two straight lines with different slopes having a break point at ∼820°C in both air and carbon dioxide. The Jander activation energies for anatase in the higher and lower temperature regions were ∼340 and ∼290 kj · mol−1, respectively, and those for rutile in air and carbon dioxide were 340 and 390 KJ · mol−1, respectively.

A drastic drop of the electrical resistivity was observed on a ferroelectric insulator BaTiO3 surface, after KrFlaser irradiation in air at atmospheric pressure. The temperature dependence of the resistivity was employed to demonstrate semiconducting behavior. Such behavior was seen when the resistance was measured in nitrogen. When measured in air, the semiconducting layer was oxidized and the insulating behavior restored.