Investigation of Glass-forming Region and Performance Optimization in Lead-free SnO-CaO-P_2O_5 System

Lead-free glass in SnO-CaO-P2O5 ternary system were fabricated by melt quenching method.The glass-forming region,coefficient of thermal expansion(CTE),volume resistivity as well as chemical durability of the glass were investigated by the methods of X-ray diffractometer,thermal expansion instrument,insulation resistance instrument,and grain mass loss method.The results show that the glass-forming region is larger than that of SnO-ZnO-P2O5 ternary system.The minimum content of P2O5 to form glass phase should be 25mol%,while it increases rapidly to about 40mol% with the increase of CaO amount.Softening temperature(about 445 ℃) and CTE(9.0×10-6-10.0×10-6/℃) of the glass are equivalent with those of Pb-based sealing glass.The volume resistivity presents a maximum at about 50mol% P2O5 content with the increase of P2O5 amount,while it decreases with the increase of SnO amount.Research on the samples of 10SnO-40CaO-50P2O5-xSiO2 system show that with the increase of SiO2 amount,the CTE decreases from 9.8×10?6/℃ to 7.6×10?6/℃ and the volume resistivity increases gradually,while the mass loss decreases gradually in acid and neutral condition and increases in basic condition.