A peroxo titanic acid (PTA) solution has been prepared by mixing titanic acid wet gel and hydrogen peroxide solution. The PTA solution was a neutral, transparent, stable liquid. The PTA crystallized to form an anatase phase after calcination at a temperature above 250. When the PTA solution was autoclaved at a temperature above 100 for 6h, it changed to a sol containing anatase crystals less than 20nm in diameter. Aggregation occurred after autoclaving at a temperature above 120. When the PTA solution was heated to 100, it was translucent and stable in spite of containing ultrafine anatase crystals (9nm in diameter). It was deduced that the surfaces of anatase crystals are modified by the peroxo groups.

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There is no standardized method in Japan for the estimation of impact strength for strengthened porcelain table ware. In many cases, a measurement is carried out by ASTM C368 using a pendulum formula impact tester. However, there are many unknown factors about statistical dispersion in impact strength values, and the relation between the number of tested samples and accuracy of measurement. In this experiment, the impact measure ment was carried out using a large number of high strength porcelain tableware. The dispersion in impact strength values was confirmed to show a normal distribution statistics, and the relation between the number of samples and measurement accuracy was discussed. Furthermore, it was revealed that the impact strength value was also influenced by the shape and weight of the impact hammer head.

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