| Phosphate glasses have drawn much attention as promissing canditate for the numerous commercial applications, such as adhesives for glass, ceramics or metal materials, sealing or coating frits for electronic components, conductive or resistive pastes, due to the low transtion temperature, adjustable coefficient of thermal expansion and low cost. However, phospate glasses typically have a relatively poor chemical durability and moisture degradation which often limits their usefulness in wide application. Therefore, the improvement of chemical durability becomes the importance for every researcher on phosphate glasses. In recent years, several studies have shown that the chemical durability of phosphate glasses can be improved by addition of various oxides such as Al2O3, Fe2O3, ZrO2, MnO2, Cr2O3 etc.The ZnO-Sb2O3-P2O5 system glasses were fabricated by melt quenching method and the strucrures and properties were analysed by IR and DTA. The physical and chemical properties include CTE, density and chemical durability were measurement. Moreover, the effect of Na2 O, CaO,Bi2O3 and Al2O3 addition on structure and properties in ZnO-Sb2O3-P2O5 system glasses was studied.The results of IR indicated an increase in the intensity of symmetric vibrations of P-O-P bond, which was confirmed by the improvement of water durability with the increasing amount of Na2 O in the range of(0-10 wt. %). Substitution of 10 wt. % Na2 O led to the weight loss of the glass to 5.93 mg/cm-2 after immersion in deionized water at 50 oC for 24 h. The results of XRD showed that the ability of crystallization decreased, indicating the good thermal stability of the glass. The glass containing 8 wt. % Na2 O had the best properties in every respect and might be an alternative to lead based glasses for the applications, providing further composition improvement.The results showed that there were no noticeable changes in structure of phosphate glasses. Moreover, the glasses transition temperature and softening temperature in ZnO-Sb2O3-P2O5- CaO system glasses increased with the increasing CaO content and the water durability of the glasses increased. The decrease in the density and molar volume of the glasses was small, which was due to the similar oxide molar volume and molecular weights of CaO and ZnO. Both the CTE and thermal stability increased first and then decreased with the increasing CaO content.That there were no noticeable changes in structure of phosphate glasses. Moreover, the glasses transition temperature and softening temperature in ZnO-Sb2O3-P2O5-Na2O-Bi2O3 system glasses changed with the same tendency and the water durability of the glasses increased with the increasing Bi2O3 content. The properties of water durability could be contend to the demand of lead-free sealing glasses in B6 and B10.The decrease in the density and molar volume of the glasses was small, which was due to the similar oxide molar volume and molecular weights of Bi2O3 and Sb2O3. The CTE increased first and then decreased with the increasing Bi2O3 content. The crystallization was enhanced notably firstly and then gently with the increasing Bi2O3 content.The P-O-Sb linkages disappeared when the glass contained 5wt.% Al2O3. Meanwhile, the bending vibration of P-O bond also disappeared with the disappearing of P-O-Sb linkages. In addition, the absorption peaks of the asymmetric and symmetric vibration of P-O-P bonds moved to the high frequency and the intensity increased with the increasing Al2O3 content. The characteristic temperature increased markedly and the CTE decreased effectively with the increasing Al2O3 content. The chemical durability and the ability of corrosion resistant in molten salt could satiafy the demand of property in preparation on the optical waveguide materials. |
PDF Full Text Request