| Study on the Water Durability of Molybdate Glasses with B2O3 as Low Temperature Sealing Materials |
| Jae-Young Shin, Jae-Min Cha, Dae-Sung Kim, Dea-Geol Jeong, Jun-Hyeon Bae, Bong-Ki Ryu |
| Division of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea |
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Received: 8 May 2017; Accepted: 31 July 2017. Published online: 4 December 2017. |
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| ABSTRACT |
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The boron alkali molybdate glass system was investigated as lead-free low-temperature melting sealing materials, with different boron oxide contents between 0 and 8 mol%. The glasses were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared spectroscopy (IR), and by densities. Their chemical properties were measured by their dissolution rates (DR) and by Product Consistency Test (PCT). As the boron oxide contents were increased, the glasses maintained their low temperature properties (Tg under 175 ℃) and new network formers of [BO3] triangular units and [BO4] tetrahedral units appeared. The results confirmed that boron oxide doped molybdate glass is a candidate low-temperature sealing material. The introduction of small amounts of B2O3 causes a change in the amorphous network’s main structural units from molybdate units to a mixture of molybdate and borate units. The glasses possess MoO4, MoO6, BO3 and BO4 groups as basic structural units. In this study, the amount of MoO3 was much higher than that of B2O3, so the boroxol ring structure occurred much less frequently than molybdates as a network former. But addition of B2O3 leads to an increase in the number of bridging oxygens and strengthens the glass network. As a result, the overall glass system becomes more rigid, and chemical durability is improved. |
| Keywords:
lead-free low-melting sealing glass, molybdenum, boron oxide, glass structure |
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