Dependence of the oxygen content of boron nitride on heat-treatment temperature and its effect on the structure and strength characteristics of this compound
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A method is described for determining oxygen in active boron nitride powders by neutron activation analysis.
It is shown that raising the heat treatment temperature from 1300 to 1500°C decreases the oxygen content of boron nitride synthesized at 900°C from boric acid and urea in an ammonia stream by about three quarters; at the same time, the crystal lattice structure of the compound becomes transformed from turbostratic to mesographitic.
The hypothesis is advanced that the imperfect structure of boron nitride is caused by oxygen implanted in its crystal lattice.
At the drying temperature water-containing boron nitride undergoes hydrolysis, with the formation of various oxygen-containing compounds, including B2O3.
Use of neutron activation analysis may in many cases enable a materials (elements) balance sheet to be drawn up.
KeywordsHeat Treatment Boron Crystal Lattice Oxygen Content B2O3
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