Structural, Dielectric, and Thermal Properties of Pb Free Molybdate Based Ultralow Temperature Glass

Varghese, Jobin; Siponkoski, Tuomo; Teirikangas, Merja; Sebastian, Mailadil Thomas; Uusimäki, A.; Jantunen, Heli

doi:10.1021/acssuschemeng.6b00721

Cited by 50 publications

(23 citation statements)

References 71 publications

(108 reference statements)

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“…Microwave dielectric ceramics have been extensively used as key materials in dielectric resonators, filters, antennas, strip lines, and phase shifters for reasons of low cost, stability, efficiency, and ease of use . Recently, to meet the increasing demands for miniaturization and integration, low‐temperature cofired ceramics (LTCC) technology has become crucial due to its ability to integrate a versatile mix of passive microwave components to fabricate highly integrated multichip modules .…”

Section: Introductionmentioning

confidence: 99%

Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity

Yin

Xiang

et al. 2018

J Am Ceram Soc

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A low‐permittivity dielectric ceramic Li2GeO3 was prepared by the solid‐state reaction route. Single‐phase Li2GeO3 crystallized in an orthorhombic structure. Dense ceramics with high relative density and homogeneous microstructure were obtained as sintered at 1000‐1100°C. The optimum microwave dielectric properties were achieved in the sample sintered at 1080°C with a high relative density ~ 96%, a relative permittivity εr ~ 6.36, a quality factor Q × f ~ 29 000 GHz (at 14.5 GHz), and a temperature coefficient of resonance frequency τf ~ −72 ppm/°C. The sintering temperature of Li2GeO3 was successfully lowered via the appropriate addition of B2O3. Only 2 wt.% B2O3 addition contributed to a 21.2% decrease in sintering temperature to 850°C without deteriorating the dielectric properties. The temperature dependence of the resonance frequency was successfully suppressed by the addition of TiO2 to form Li2TiO3 with a positive τf value. These results demonstrate potential applications of Li2GeO3 in low‐temperature cofiring ceramics technology.

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Section: Introductionmentioning

confidence: 99%

Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity

Yin

Xiang

et al. 2018

J Am Ceram Soc

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“…7) By adding alkali oxides, molybdate glasses with ultra-low thermal properties are obtained, as shown in, for example, In the study by Vaghese, There is, however, a practical limit on sealing applications because of their poor chemical durability. 8) We reproduced Varghese's experiments and produced alkali molybdate glass, finding that its surface reacts with atmospheric water vapor. For practical applications, it will be necessary to improve chemical durability of the molybdate glasses, especially their water solubility.…”

Section: )4)mentioning

confidence: 88%

Structural, thermal, and chemical properties of boron oxide-doped molybdate glass for use as a lead-free low-temperature sealing material

Shin

Ryu

2017

J. Ceram. Soc. Japan

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For lead-free low-melting sealing materials, the boron oxide alkali molybdate glass system was investigated with different boron oxide contents between 0 and 8 mol %. The glasses were characterized using differential scanning calorimetry, and infrared spectroscopy, and by their dissolution rates and densities. As the boron oxide contents increase, the glasses maintain their low temperature properties (T g under 175°C), and new network formers of [BO 3 ] triangular units and [BO 4 ] tetrahedral units appear. The glasses possess MoO 4 , MoO 6 , BO 3 and BO 4 groups as basic structural units, and existing weak MoOMo bridge bonds convert into strong MoOB bridge bonds. As a result, chemical durability is improved.©2017 The Ceramic Society of Japan. All rights reserved.Key-words : Lead-free low-melting sealing glass, Molybdenum, Boron oxide, Structure [Received April 26, 2017; Accepted September 8, 2017] Sealing glass has applications in vacuum engineering and in electronics. In the development of optical elements and electronic devices, advanced sealing materials are needed, which do not damage the substrates as a result of their sealing temperatures. 1)4)This has led to specialized research on sealing glasses. Lowtemperature sealing glasses typically involve lead-based glass, but lead presents problems for human health and the environment.2),3) The properties required in sealing glasses are a low transition temperature (T g ), a low softening temperature (T s ), chemical durability, and low cost.2) Molybdate glass systems satisfy these properties, especially the low temperature properties.Molybdates have a high coordination number, favoring crystallization during cooling, and rapid quenching can be used to promote glass formation; However, this is not the only process available, as molybdates are conditioning formers. 5),6) Molybdate glasses also have characteristics that make them candidates for practical applications such as amorphous semiconductors and solid electrolytes. 7) By adding alkali oxides, molybdate glasses with ultra-low thermal properties are obtained, as shown in, for example, In the study by Vaghese, There is, however, a practical limit on sealing applications because of their poor chemical durability. 8) We reproduced Varghese's experiments and produced alkali molybdate glass, finding that its surface reacts with atmospheric water vapor. For practical applications, it will be necessary to improve chemical durability of the molybdate glasses, especially their water solubility.Glass samples with composition of xB 2 O 3 (100 ¹ x)(10Li 2 O 10Na 2 O20K 2 O60MoO 3 ) (x = 0, 2, 4, 6 and 8 mol %) (the abbreviation xBMG designates x mol %B 2 O 3 molybdate glass) were prepared using B 2 O 3 , Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 and MoO 3 obtained from the Junsei Chemical Co. (Japan). Each sample batch was mixed and ground repeatedly for homogenization. The batches were melted at 1200°C in an alumina crucible under normal atmospheric conditions for no more than 10 min to minimize volatilization of the glass...

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“…fluorophosphates glass, barium fluoride-thorium fluoride glass, phosphate glass, boron lead glass and so on [1][2][3][4][5], have been widely used in glass-metal sealing, IC packaging, Phosphor-in-Glass (PiG) host [6][7][8][9]. Specially, the tin fluorophosphates (SnF 2 -P 2 O 5 -SnO) glass, of which the glass transition temperature (Tg) value is generally lower than 200 °C, has been considered to be an excellent host of fluorescent glass in the past two decades.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Tunable white light in trivalent europium single doped tin fluorophosphates ultra-low melting glass

Mao

Cai

Xie

et al. 2019

Journal of Alloys and Compounds

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In recent years, low melting temperature glasses have received wide attention as the hosts of phosphor-converted light emitting diodes (pc-WLED). In this work, a series of trivalent europium doped tin fluorophosphates glasses were prepared by conventional melting method. Under ultraviolet excitation, the blue-green broadband emission from Sn 2+ activation centers in the glass matrix and the red emission of Eu 3+ ions together constituted a cool white luminescence. The spectra analysis was used to demonstrate the energy transfer between Sn 2+ centers and Eu 3+ ions. The results showed that Sn 2+ and Eu 3+ possessed independent intrinsic emission and mutual energy transfer simultaneously. The 5 D 4 and 5 G 2 excited states of Eu 3+ ion favored the energy transfer to Sn 2+ center, the 5 L 6 excited state of Eu 3+ ion would absorb more of the energy by the Sn 2+ ground state excitation to contribute on red emission. Therefore, the fluorescent glass can transform cool white light to warm white light by changing the excitation wavelength. The tunable white light is obtained in the WLED devices built with the glass and commercial UV chips.

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Structural, Dielectric, and Thermal Properties of Pb Free Molybdate Based Ultralow Temperature Glass

Cited by 50 publications

References 71 publications

Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity

Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity

Structural, thermal, and chemical properties of boron oxide-doped molybdate glass for use as a lead-free low-temperature sealing material

Tunable white light in trivalent europium single doped tin fluorophosphates ultra-low melting glass

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Structural, Dielectric, and Thermal Properties of Pb Free Molybdate Based Ultralow Temperature Glass

Cited by 50 publications

References 71 publications

Low‐temperature sintering and thermal stability of Li2GeO3‐based microwave dielectric ceramics with low permittivity

Low‐temperature sintering and thermal stability of Li2GeO3‐based microwave dielectric ceramics with low permittivity

Structural, thermal, and chemical properties of boron oxide-doped molybdate glass for use as a lead-free low-temperature sealing material

Tunable white light in trivalent europium single doped tin fluorophosphates ultra-low melting glass

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Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity

Low‐temperature sintering and thermal stability of Li₂GeO₃‐based microwave dielectric ceramics with low permittivity