B. S. Lunin, A. N. Kharlanov, S. E. Kozlov Dehydration and formation of KU-1 silica glass surface defects under annealing Abstract Formation of KU-1 silica glass surface defects at annealing is considered. Based on experimental data obtained by annealing of silica glass samples in temperature range 800-980°C, it is showed that internal stress forming due to dehydration of surface zone is main cause of the surface defects. To determine the depth of this zone for different annealing conditions a formula is suggested. It shows that the internal stress is less than critical one and silica glass surface is not changed if annealing temperature is 850°C or more due to fast relaxation rate. Under lower annealing temperature the surface defects are formed in a few dozens of hours at annealing.
Copyright (C) Chemistry Dept., Moscow State University, 2002 |
|