No abstract

The melting temperatures of natural and synthetic monazite and xenotime (rare‐earth ortnophosphates) were measured, using a heliostat‐type solar furnace. The results obtained are as follows: natural monazite from Japan (2057°40°C), synthetic monazite RPO4 (R=La, 2072°20°C; R=Ce, 2045°20°C; R=Pr, 1938°20°C; R=Nd, 1975°20°C; R=Sm, 1916°20°C), and synthetic xenotime RPO4(R=Y, 1995°20°C; R=Er, 1896°20°C).

A porous titania ceramic with a woodlike microstructure that was analogous to silicified wood was prepared. The production of "titanified wood" was performed using the following process: (i) introduction of titanium tetraisopropoxide into wood materials via vacuum infiltration, (ii) hydrolysis of the titanium tetraisopropoxide in the cell structure to form a titania gel, and (iii) firing at a temperature of 600°-1400°C in air. The resulting titania ceramic had the same external and internal forms of the original wood.