Fabrication of a nanoporous Na2O-B2O3-SiO2 glass plate with controlled pore size

In this work, fabrication of a nano porous 7.5Na(2)O center dot 26.5B(2)O(3)center dot 66.0SiO(2)(NBS) glass plate with controlled pore size was examined using mercury intrusion porosimetry and scanning electron microscopy. When the NBS samples were heat treated at various temperatures for 24 h and then leached in a 0.5 N HCl solution at 95 degrees C for 24 h, the pore size was concentrated in the 20 to 90 nm range. The surface area decreased from 22.63 to 6.50 m(2)g(-1) as the treatment temperature rose from 580 to 640 degrees C. However, other pore properties, such as pore volume, average pore diameter and porosity, increased as the treatment temperature rose from 580 to 620 degrees C, then decreased when treated at 640 degrees C. The NBS samples were observed to have a three-dimensional interconnected structure when they were heat treated at temperatures between 600 and 640 degrees C for various times. The fracture and crack rates were 0 and 10%, respectively, when the NBS samples were heat treated at 620 degrees C for 24 h and subsequently leached in a 0.5 N NaOH solution at room temperature for 2 h; the results was reveal that the average pore size of sample through alkali leaching (90.7 nm) was slightly smaller than that of the samples without alkali leaching (914 nm).