| 摘要 |
PURPOSE:To obtain the titled composition capable of sealing mainly illumination glass parts at a low temperature without causing deformation of the parts nor devitrification and discoloration of the sealed part, by compounding powder of PbO-B2O3 type glass with refractive filler powder having low expansion coefficient at a specific ratio. CONSTITUTION:The objective sealing glass composition is composed of (A) 70-95(wt)% PbO-B2O3 type low melting glass powder having softening point of <=370 deg.C (powder having a composition of 75-85% PbO, 5-20% B2O3, 0.5-5% SiO2, 0.5-3% Al2O3 and 0.1-2% one or more components selected from Li2O, Na2O, K2O and F) and (B) 5-30% refractive filler powder having low expansion coefficient (e.g. lead titanate and/or zirconium silicate). The composition can be welded at <=450 deg.C. Especially, glass parts such as bulb or tube of illumination glass can be welded without deformation when used for the sealing of illumination glass. Furthermore, since devitrification nor discoloration takes place at the sealed part, there occurs no deterioration of the brightness of illumination and appearance of the illumination fixture and the glass is extremely suitable for the sealing of illumination glass parts.
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