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Izumi, Japan

Takemiya T.,Kagoshima University | Yoshida M.,Kagoshima University | Kouhara Y.,Yamato Electronics Co.
Kagaku Kogaku Ronbunshu | Year: 2011

Lead-free glasses with low melting point, low thermal expansion, and waterproof durability are desirable for the sealing process in the ceramic and electronic fields. In this study, V 2O 5, Li 2O, and TeO 2 were used to prepare lead-free sealing glasses with low melting temperature. The glass-forming region, glass transition temperature, softening temperature, crystal precipitation temperature, thermal expansion property, and X-ray confirmation were investigated in detail for the ternary (V 2O 5-Li 2O-TeO 2) system. The dependencies of these properties on composition were quantitatively characterized. The ternary system glass (10-40 mol%V 2O 5-0-40 mol%Li 2O-30-70 mol%TeO 2) had a low melting property and an amorphous structure. Addition of a low thermal expansion ceramic filler, Zr 2(WO 4)(PO 4) 2 (ZWP), to the prepared lead-free glasses yielded glasses with a similar coefficient of thermal expansion (7.0-8.0X10× 6°C×1) to plain soda lime glass. In particular, glass prepared with 80 wt% V-Li-Te-12 (10 mol% V 2O 5-20 mol% Li 2O-70 mol%TeO 2) and 20 wt% ZWP had an excellent waterproof durability and adhesion strength of 1.6 kgf/cm 2. © 2011 The Society of Chemical Engineers, Japan. Source


Tsuruda K.,Kagoshima University | Kubo S.,Kagoshima University | Matsuo F.,Kagoshima University | Sonae K.,Kagoshima University | And 4 more authors.
Kagaku Kogaku Ronbunshu | Year: 2015

We prepared and evaluated the heat characteristics, thermal expansion, water durability, transparency, and sealing strength of glasses comprising 30–80 mol%Li2 B4 O7 , 10–40 mol%BaO, and 10–40 mol%P2 O5 . Addition of Al2 O3 to the Li2 B4 O7 –BaO–P2 O5 glasses was found to improve their transparency. In particular, glass comprising 53.0 mol%Li2 B4 O7 , 15.2 mol%BaO, 7.6 mol%P 2 O 5 , 24.2 mol%Al 2 O 3 (LiBaP+24.2Al) had high transparency, high water durability, and a low thermal expansion coefficient equal to that of soda lime glass without the addition of a low thermal expansion ceramic filler. Furthermore, the LiBaP+24.2Al glass had high sealing ability (6.64 kgf/cm 2) compared to lead glass (1.63 kgf/cm2). © 2015, The Society of Chemical Engineers, Japan. Source


Matsuo F.,Kagoshima University | Kubo S.,Kagoshima University | Kouhara Y.,Yamato Electronics Co. | Takei T.,Kagoshima University | Yoshida M.,Kagoshima University
Kagaku Kogaku Ronbunshu | Year: 2015

This study aimed to develop a lead-free sealing glass applicable to sealing of the alkali-free glass included in 4K televisions and organic light-emitting diode digital displays. The sealing glass should ideally possess the following properties: (i) free of alkali metals, (ii) low melting point, (iii) low thermal expansion and (iv) high water durability. To meet these requirements, we prepared glasses with combinations of four different metal oxides (V2O5, ZnO, TeO2and (ZrO)2(HPO4)2) and evaluated their properties. Two types of lead- and alkali metal-free glasses (40 wt% V2O5–10 wt% ZnO–40 wt% TeO2–10 wt% (ZrO)2(HPO4)2and 40 wt% V2O5–8 wt% ZnO–40 wt% TeO2–12 wt% (ZrO)2(HPO4)2) were found to have low melting points, low thermal expansion coefficients and high water durability. However, further reduction of their thermal expansion coefficient was necessary for successful sealing of alkali-free glass. To this end, we incorporated ZWP (Zr2(WO4)(PO4)2), a low thermal expansion ceramic filler, into the sealing glasses. This resulted in reduction of the thermal expansion coefficient and successful sealing of alkali-free glass. These results show that V2O5– ZnO–TeO2–(ZrO)2(HPO4)2 glass is promising for sealing of 4K televisions and organic light-emitting diode digital displays. © 2015 The Society of Chemical Engineers. All rights reserved. Source


Goto S.,Kagoshima University | Kouhara Y.,Yamato Electronics Co. | Takei T.,Kagoshima University | Yoshida M.,Kagoshima University
Kagaku Kogaku Ronbunshu | Year: 2013

Lead-free glasses with a low glass transition temperature, low coefficient of thermal expansion, high fluidity and high durability against water are desirable for sealing of electrical devices. In this study, V2O5, H2WO4, and KPO3 were used to develop a novel sealing glass. We investigated the glass transition temperature, softening temperature, glass crystallization temperature, coefficient of thermal expansion and ratio of weight loss of glasses after waterproof testing. Amorphous glasses were obtained by melting of mixtures of V2O5 (10-60 mol%), H2WO4 (10-50 mol%), and KPO3 (30-70 mol%). Two types of glass (40 mol% V2O5-20 mol% H2WO4-40 mol% KPO3 and 40 mol% V2O5-10 mol% H2WO4-50 mol% KPO3) had low glass transition temperature and good fluidity. Addition of Sb2O3 (2.5, 5 or 10 wt%) to the glasses enhanced their durability against water. The coefcient of thermal expansion of the glass composed of 39.0 mol% V2O5-9.7 mol% H2W O4-48.7 mol% KPO3-2.6 mol% Sb2O3 was lowered by incorporation of Zr2(W O4) (PO4)2, a low-thermal-expansion ceramic fller. Te glass showed comparable bonding strength with a commercial lead glass. © 2013 The Society of Chemical Engineers, Japan. Source


Kubo S.,Kagoshima University | Goto S.,Kagoshima University | Iwata R.,Kagoshima University | Kouhara Y.,Yamato Electronics Co. | And 2 more authors.
Kagaku Kogaku Ronbunshu | Year: 2014

Lead-free sealing glasses possessing low melting temperature, high water durability, low thermal expansion coefficient, and high fluidity are desirable for sealing processes in the ceramics and electronics fields. In this paper, novel sealing glasses composed of metal and non-metal oxides (V2O5, MnO2 and KPO3) were developed, and their thermal properties, water durability, structure by X-ray or FT-IR analysis, fluidity by flow-button test, lightness by the Munsell value, sealing properties, and bonding strength by tension test were examined in detail. The glasses with low melting point and high fluidity were composed of 40 mol% V2O5-10 mol% MnO2-50 mol% KPO3, 30 mol% V2O5-20 mol% MnO2-50 mol% KPO3, or 30 mol% V2O5-10 mol% MnO2-60 mol% KPO3. However, these glasses with high phosphorus content had poor water durability, which could be improved considerably by the addition of CuO. The thermal expansion coefficients of the glasses were much higher than that of a soda lime glass (7-8×10-6°C-1) and were lowered to the level of a soda lime glass by the addition of a low thermal expansion ceramic filler (Zr2(WO4)(PO4)2, ZWP). Glass composed of 40 mol% V2O5-10 mol% MnO2-50 mol% KPO3 containing 20 wt% ZWP had an excellent sealing property comparable to commercial lead glass. © 2014 The Society of Chemical Engineers, Japan. Source

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