Synthesis And Properties Research On Aluminoborosilica Sealing Glasses

Sealing glasses have a great prospect in modern electric industry because of their outstanding chemical stability, low cost, excellent insulation and the controllable composition. They have started to substitute other types of sealing component gradually such as organic polymer, metal and so on. Sealing glasses would be the first choice when used in mid-high temperature situation due to their well thermal stability and high resistance, and at the same time good thermal match can be fit by change the composition of the glasses. Therefore they also be applied in many other fields like communication and aerospace etc.This subject is on sealing glasse used in tantalum electrolytic capacitor. Tantalum capacitor has fabulous capacitance, low breakdown rate and internal resistance. It has a developing trend in need. However the sulfuric acid in capacitor may leak out and corrode the surrouding components if the sealing is not tight enough. For this reason sealing glass is needed to seal up the capacitor. The research on sealing glasses was almost in solid oxide fuel cell at present and this research is also about sealing glass but with low thermal expansion coefficient.Borosilicate glass is a large part of sealing glasses, which always consists of silica and boron oxide, to be provided with well chemical stability and heat resistance. The alumino-borosilicate glass has special properties in electricity and photology. Generally silicate glass is more stable than borate glass and phosphate glass and this subject is planning to focus on borosilicate glass. But silicate glass is also affected by the composition severely. The target of this subject is to obtain well-performed glass by changing the composition.Comparing with the general method of manufacturing glass, sol-gel method is more efficient in utilizing raw material and also environmental-friendly. This subject is to use silicic acid tetracthyl ester and nitrate solution making vitreous precursor, after drying the precursor and calcining glass is obtained. Through XRD test, differential thermal analysis and acid resistance test, the results are got and then be analyzed.Consequently we found that it made a big difference when the different alkali metal and alkaline-earth metal oxide added in the SiO2-B2O3-AL2O3glass. They would change the post-mortem crystal degrees and thermal characteristic temperature as well the average thermal expansion coefficient. The result of acid resistance test showed the most influential factor was the type of added oxide but not process. The loss was maximal when magnesium oxide added in glass, then followed calcium oxide and barium monoxide. We also found the increasing of nSiO2/nB2O3resulted in a greater hardship for crystallization and the result of IR showed the structure in glass had varied.