The fused quartz is one of the most typical materials of ion: thermal
expansion. However, it was found that compacts prepared by isostatic c
ompression of ground powder of fused quartz showed an anomalously high
thermal expansion of 7 x 10(-6)/degrees C, i.e., about 10 times of th
at of the normal fused quartz, The density of the glass powder increas
ed with grinding time and with increasing pressure of compaction, Rele
ase of the compaction strain by heating can be the reason of this high
thermal expansion of the compacts of fused quartz powder.