Preparation and Properties of lead-free glass powder
|School||Kunming University of Science and Technology|
|Keywords||Lead-free glass powder Transition temperature Chemical stability conductivity Adhesion|
Glass frits is the important component of silver paste, its nature directly affect the properties of silver membrane. Glass frits in traditional silver paste is lead glass frits, Lead glass frits which used for binding element have excellent properties in many aspects, but lead considerable damage to the environment and people, as people of environmental protection consciousness to strengthen and the major developed countries had to legislate law to ban use and production the silver paste of containing lead, therefore, it is imperative for the development and application glass frits of lead-free.This paper mainly studied the production of low melting point glass frits which use for silver paste and related properties of glass had been studied. Properties of low melting point glass frits had been studied which based Bi2O3-B2O3-SiO2 system and performance adjusting oxide of Li2O、MgO、NaF、TiO2 and ZnO added in this system, through differential thermal analysis, acid-proof and acid-alkaline testing, The effects of Li2O、MgO、NaF、TiO2and ZnO on the soften point and chemical stability of glass was studied in details. The effects of MgO、TiO2 and ZnO on thermal properties were being discussed. Some explanations about the effects of Li2O and NaF on the soften point and melting point of glass frits were given out. In conclusion, based on the experimental and theoretical analysis, the optimized composition of the glass frits was given out:quality percentage of B2O3 is 10% to 19%, SiO2 is 5% to 15%, Bi2O3 is 45% to 70%, Al2O3 is 2% to 8%, Li2O is 1% to 5% MgO is 1% to 6%, NaF is 1% to 3%, TiO2 is 1% to 5%, ZnO is 1% to 7%. By using this formulation, the low temperature and lead-free glass frits with soften point is 462℃was successfully prepared, This lead-free glass frits of acid-proof and acid-alkaline is good. The XRD pattern of this glass frits showed that lead-free frits has the glass typical amorphous structure and the performance of forming glass was very good and the range of extension was very wide. Differen-tial thermal analysis (DSC) studies show that lead-free glass frits is microcrystalline glass. In this paper, the mechanism of action and effects of the lead-free glass frits with silver paste on electric conductivity and the adhesion strength were studied. The silver paste with the lead-free glass frits suitable for sintering at 630℃and the best time for keeping this temperature is 6min. High sintering temperature and longer holding time will make the conductivity of silver film becoming poor. The silver paste with quality percentage of the lead-free glass frits at 5% and size at around 3μm can obtain higher electric conductivity and the adhesion strength.