降温速率对浮法硼硅酸盐玻璃下表面渗锡的影响

研究锡槽中降温速率对浮法硼硅酸盐玻璃下表面渗锡的影响.采用不同降温速率制备浮法硼硅酸盐玻璃,用电子探针测试浮法硼硅酸盐玻璃在1 250～650℃温度范围内不同降温速率情况下表面渗锡分布情况.研究结果表明:浮法成形过程中硼硅酸盐玻璃渗锡的深度可达到40.0μm左右,并且在1 050℃以上的高温段锡离子以深度方向扩散为主,在1 050℃以下的低温阶段锡离子主要在玻璃的近表面富集.随着时间的延长浮法硼硅酸盐玻璃近表面的渗锡量增加,而深度大于7.0μm以上的内部的渗锡量不会由于时间的延长而累加,只与温度有关.在浮法成形过程中渗锡曲线会在1 050℃左右,距玻璃表面15.0μm处出现卫星峰,但最终在低温时该卫星峰会由于逆扩散而消失.

EFFECT OF COOLING RATE ON TIN PENETRATION IN THE SUBSURFACE LAYER OF FLOAT BOROSILICATE GLASS

The float process of float borosilicate glass was simulated by a minitype graphite tin bath. The glass samples were pro-duced at different cooling rates from 1 250 ℃ to 650 ℃. The tin depth profiles were studied by electron probe microanalysis. It wasfound that tin diffused into the borosilicate glass with a total penetration depth of 40.0 μm. Tin ions mainly diffused into the interiorof the borosilicate glass at higher temperatures (>1 050 ℃) and entered the near-surface at lower temperature (<1 050 ℃). Theamount of tin in the near-surface is increased with the prolonging of time, but the amount of tin in the interior deeper than 7.0 μmremains invariable with time. In the whole float process, the tin depth profiles show a satellitic peak at 15.0 μm depth, but the satel-litic peak disappeares at the lower temperature range of the tin bath.