Structure And Properties Of Bismuth System Low Melting Electronic Glasses

It was a current that the heat elements made of medium coat with the minitype development of the home-wirings. The low-melt point electronical glass used for electric materials, resistance materials and insulation coat materials was sdudied and applied rapidly. The lead system low-melt point glass was the most important low-melt point electronical glass. This system glass was used very broad because of it's advantage in intenerate temperature, insulation, low cost and so on. But with the improve of the environment-protect standard, the lead system glass had been instead of others systems low-melt point glass.In this paper, against the application limit of the the lead system low-melt point glass, the lead-free bismuth system low-melt point glass instead of lead system glass was put forward. The composition Bi₂O₃-B₂O₃-ZnO-Al₂O₃-SiO₂ system glass were designed. By cross-research, the formation, the intenerate temperature, the insulation capability and other electronical performance of the bismuth system glass whose Bi₂O₃ between 65% and 85% were research detailedly. The performance and the structure of the different composition glass were analysed by many testing methods such as the DTA, the infrared spectra, the XRD, the volume resistivity, the dielectric constant, the dielectric loss and so on. To confirm the bismuth system glass forming region that the performance were up to the mustard., the function and the influence with it's content change of the other oxids in the glass composition were research respectively. The practicality low-melt point and high-insulation electronic glass materials were made.The results of the experiments indicated that Al₂O₃(wt%)=4.5 was a good point when 80≤Bi₂O₃(wt%)≤85; And the performance of the glass was the best at the point of ZnO/Al₂O₃=1; When 75≤Bi₂O₃(wt%)≤80, it could improve the performance of the glass if the glass components add a small amount of SiO₂. The intenerate temperature and the volume resistivity of the glass increased with increasing B₂O₃ content.The dielectric loss decreased with increasing B₂O₃ content. The hemisphere temperature between 500℃and 520℃, the volume resistivity was over 10¹⁴Ω·cm, the dielectric loss was about 0.003.The influence in the performance and the structure of the glass were researched when a small amount of mica powder added. When the additives of mica control in the 3%-5% range, It could increase the volume resistivity 10 times, however, there was less influence for the hemisphere temperature and the dielectric loss.