Effect of Bi2O3 on Thermal Properties of Barium-Free Glass-Ceramic Sealants in the CaO-MgO-B2O3-Al2O3-SiO2 System

2015 ◽  
Vol 659 ◽  
pp. 180-184 ◽  
Author(s):  
Pornchanok Lawita ◽  
Apirat Theerapapvisetpong ◽  
Sirithan Jiemsirilers
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Thermal Treatment ◽  
Glass Ceramic ◽  
Mechanical Stability ◽  
Coefficient Of Thermal Expansion ◽  
Softening Temperature ◽  
X Ray Diffraction ◽  
Free Glass

Barium-free glass-ceramic sealants for the planar solid oxide fuel cell (pSOFC) have attracted considerable attention to avoid the crystallization of the high coefficient of thermal expansion (CTE) BaCrO4; reaction product at the interface between barium-containing glass-ceramic sealants and Crofer22 APU interconnect, which decreases the long-term mechanical stability of the sealant. In this study, Barium-free glass-ceramic sealants in the CaO-MgO-B2O3-Al2O3-SiO2 system with varying amounts of Bi2O3 from 0 to 10 wt. % were prepared by conventional melting and their thermal properties were investigated. The glass transition temperature (Tg), dilatometric softening temperature, and coefficient of thermal expansion (CTE) were determined by a dilatometer. The Tg, onset of crystallization (Tx) and crystallization temperature (Tc) were obtained from DTA. Results of phase analysis by X–ray diffraction of glasses after thermal treatment at 900 oC for 2 h indicated that the major phase of all glasses was diopside (MgCaSi2O6) and minor phases were åkermanite (Ca2MgSi2O7) and forsterite (Mg2SiO4). The Tg of the fabricated glasses tended to decrease with increasing Bi2O3 content while the CTE of glasses increased after the thermal treatment and was in the range of requirement for SOFC sealant.

Influence of Bi2O3 on Crystalline Phase Content and Thermal Properties of Åkermanite and Diopside Based Glass-Ceramic Sealant for SOFCs

2017 ◽  
Vol 751 ◽  
pp. 483-488
Author(s):  
Pornchanok Lawita ◽  
Apirat Theerapapvisetpong ◽  
Sirithan Jiemsirilers
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Glass Ceramic ◽  
Crystalline Phase ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Clean Energy ◽  
Softening Temperature ◽  
Quantitative Phase Analysis ◽  
Clean Energy Source

Solid oxide fuel cell (SOFC) is an electrochemical energy conversion device which is considered as clean energy source generator with reliability and relatively inexpensive production cost. One of the most important components for planar design SOFC is the hermetic seal that prevents fuel from leaking out of between the stack of fuel cells. Glass-ceramics are attractive materials as sealing materials for this device. The expected coefficient of thermal expansion (CTE) of the glass-ceramic sealants should be between 9 and 12 x 10−6 K−1. Glass – ceramics based on åkermanite (Ca2MgSi2O7) crystalline phase were reported their high CTE value from about 10 to 11.3 x 10−6 K−1. In this study, glass compositions in the CaO-MgO-B2O3-Al2O3-SiO2 system with varying amounts of Bi2O3 from 0 to 10 wt. % were prepared by conventional melting and investigated their properties. The selected compositions were derived from ternary åkermanite–forsterite–anorthite phase diagram. Phase composition and quantitative phase analysis of glass–ceramics were examined by X-ray diffractometer. The onset of crystallization (Tx) and crystallization temperature (Tc) were measured by DTA. The thermal properties of bulk glass samples and heat treated samples at 900 oC for 2 h which were glass transition temperature (Tg), dilatometric softening temperature (Ts), and coefficient of thermal expansion (CTE) were determined by dilatometer. Furthermore, the long-term stability of their CTE was investigated. The samples were continued to soak at 800 °C for 100 h and observed their change in CTE value. The results found that the åkermanite phase tended to increase with increasing amount of Bi2O3 content.

The Effect of Li2O and B2O3 on Thermal Properties and Chemical Solubility of Low-Fusing Dental Porcelain

2005 ◽  
Vol 284-286 ◽  
pp. 917-920
Author(s):  
Dae Jin Ko ◽  
Kyoung Nam Kim ◽  
Yong Keun Lee ◽  
B.H. Kim ◽  
Kwang Mahn Kim
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Softening Temperature ◽  
Glass Frit ◽  
Dental Porcelain ◽  
Alkali Oxides

Alkali oxides were added to glass frit in order to lower the firing temperature of dental porcelain, and the effects of Li2O and B2O3 on the thermal properties and chemical solubility of low-fusing dental porcelain were investigated. The glass transition temperature(Tg) and softening temperature(Ts) of glass frits were decreased remarkably by adding Li2O, but the coefficient of thermal expansion(CTE) was increased with Li2O. In the case of adding B2O3, the thermal properties were unchanged. Tg of B0L4, B2L4 and B4L4 specimens were lower than 500°C and Ts were lower than 550°C. The chemical solubility of prepared low-fusing dental porcelain with these glass frits were 37.3, 43.9, and 49.2µg·cm-2 respectively. The chemical solubility was increased by adding Li2O and B2O3, but all the results were below 100µg·cm-2 and satisfactory to ISO Standards. Further, the chemical solubility of the commercial low-fusing dental porcelains were 52.6µg·cm-2 for Ceramco Finesse(Clear), 70.8µg·cm-2 for Duceram-LFC(TC) and that of conventional dental porcelain, CeraMax(T-C), was 34.8µg·cm-2.

Effect of Interconnectivity of Nickel on Electrical and Thermal Properties of Alumina-Ni Interpenetrating Phase Composite

2011 ◽  
Vol 239-242 ◽  
pp. 2679-2682 ◽  
Author(s):  
Rub Nawaz Shahid ◽  
Bin Awais Hasan ◽  
Fahad Ali ◽  
Naeem Ul Haq Tariq
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Impedance Spectroscopy ◽  
Electron Spectroscopy ◽  
Coefficient Of Thermal Expansion ◽  
Optimal Combination ◽  
Percolation Limit ◽  
Scanning Electron

In this work percolation range for Al2O3-Ni interpenetrating phase composite (IPC) was studied to find the optimal combination of electrical conductivity and coefficient of thermal expansion (CTE). The impedance spectroscopy and scanning electron spectroscopy were used to study the percolation limit.

Synthesis, structure and thermal expansion of the phosphates M0.5+x M′x Zr2−x (PO4)3 (M, M′–metals in oxidation state +2)

2017 ◽  
Vol 89 (4) ◽  
pp. 523-533 ◽  
Author(s):  
Elena Asabina ◽  
Vladimir Pet’kov ◽  
Pavel Mayorov ◽  
Dmitriy Lavrenov ◽  
Igor Schelokov ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Treatment ◽  
Ir Spectroscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Types ◽  
The Difference

AbstractThe phosphates M0.5+x M′x Zr2−x (PO4)3 (M–Ca, Mn, Co, Sr, Cd, Ba, Pb; M′–Mg, Mn, Co) were synthesized by sol-gel method with the following thermal treatment of reaction mixtures. X-ray diffraction, IR spectroscopy and electron microprobe analysis showed that the obtained phosphates crystallized in Sc2(WO4)3 (SW) and NaZr2(PO4)3 (NZP) structural types. Both types of crystal structures are based on a framework comprised of octahedra and tetrahedra, the difference between them is fragments orientation. Thermal expansion of the phosphates was studied in the temperature range 20–800°C. Some compounds were found to belong to low-expanding materials (αav ~2·10−6°C−1).

scholarly journals Solid-state reaction in nanoparticulate alumina/LZSA glass-ceramic composites

Cerâmica ◽  
2018 ◽  
Vol 64 (371) ◽  
pp. 397-402
Author(s):  
O. R. K. Montedo ◽  
F. Raupp-Pereira ◽  
A. P. N. de Oliveira
Keyword(s):  
Solid State ◽  
Glass Ceramic ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Glass Frit ◽  
Ceramic Composites ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Dry Powders ◽  
Xrd Study

Abstract In this work, some properties, such as sinterability, modulus of elasticity (E), coefficient of thermal expansion (CTE) and dielectric constant (εr), of composites constituted by nanoparticulate alumina (27-43 nm, 35 m2.g-1) in different contents (0 to 77 vol%) and a LZSA glass-ceramic composition (17.7Li2O-5.2ZrO2-68.1SiO2-9.0Al2O3, molar basis) were evaluated. Dry powders of the raw materials (alumina and LZSA parent glass, frit) were uniaxially pressed (40 MPa) and the obtained compacts were sintered at 600-950 °C (1 h holding time). X-ray diffraction (XRD) study was performed in order to investigate the solid-state reactions occurred in LZSA-based compositions during sintering. XRD results were correlated to the CTE, E and εr of sintered samples. The CTE of the obtained composites decreased as alumina content increased mainly due to the β-spodumeness (solid solution Li2O.Al2O3.4-10SiO2) formation. The results concerning the E (22.3±1.5 GPa) and εr (3.1±1.3) for the composite with 5.6 vol% addition sintered at 850 °C for 1 h indicated, in a preliminary way, the possibility of development of materials with suitable properties for applications concerning to the low temperature co-fired ceramic (LTCC) technology.

Influence of B2O3 on Dielectric, Mechanical, and Thermal Properties of MgO-Al2O3-SiO2 Glass-Ceramics

2019 ◽  
Vol 821 ◽  
pp. 435-439
Author(s):  
Bo Li ◽  
Ke Jing ◽  
Hai Bo Bian
Keyword(s):  
Activation Energy ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Low Temperature ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Mechanical And Thermal Properties ◽  
Sintering Process ◽  
Low Thermal Expansion

Low temperature sintered MgO-Al2O3-SiO2 glass-ceramic with high mechanical and low thermal expansion was prepared for package. The remarkable influence of B2O3 addition on the electrical, mechanical, and thermal properties was fully investigated. A small amount of B2O3 promoted the sintering process and improved the densification of MAS. The kinetics via Kissinger method indicated that an appropriate B2O3 content decreased the activation energy and helped the occurrence of crystallization. Due to the increase of crystallinity and indialite phase, B2O3 addition significantly enhanced flexural strength and Young’s modulus. MAS doped with 3wt% B2O3 can be sintered at 900 °C and obtained good properties: σ = 229 MPa, φ = 86 GPa, α = 1.66×10-6 /°C, εr = 5.29, and tanδ = 5.9×10-4.

A Novel Wear Resistant Glass-Ceramic Coating Material

2011 ◽  
Vol 686 ◽  
pp. 521-527
Author(s):  
Ye Han ◽  
Shu Yu Yao ◽  
Wei Wei Zhang ◽  
Ming Gu ◽  
Yu Sui Yao
Keyword(s):  
Glass Ceramic ◽  
Ceramic Coating ◽  
Coefficient Of Thermal Expansion ◽  
Xrd Analysis ◽  
Coating Material ◽  
X Ray Diffraction ◽  
Coating Materials ◽  
Wear Resistant ◽  
X Ray ◽  
Glass Ceramic Coating

A novel wear resistant glass-ceramic coating system (based on SiO2-B2O3-Al2O3 glass system) on iron based substrate was developed. Friction coefficient, wear rate and coefficient of thermal expansion of coating material were evaluated using suitable methods. The coating materials and the resultant coatings were characterized using differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM). XRD analysis of the coating materials showed presence of a number of microcrystal. SEM micrographs indicate strong chemical bonding at the iron-ceramic interface. The coating material showed perfect properties for protection the iron substrate from abrasion.

Liquid Crystalline Thermosets As Materials For Microelectronics

1991 ◽  
Vol 227 ◽  
Author(s):  
C. K Ober ◽  
G. G. Barclay
Keyword(s):  
Thermal Expansion ◽  
Liquid Crystalline ◽  
Coefficient Of Thermal Expansion ◽  
High Thermal Stability ◽  
Isotropic Phase ◽  
X Ray Diffraction ◽  
Primary Interest ◽  
Functional Monomers ◽  
X Ray ◽  
Orientation Parameters

ABSTRACTNew liquid crystalline thermosets have been prepared from end-functional monomers and oligomers of varying molecular weight. Both triazine and epoxy networks were explored. Of primary interest was the exploitation of the mesophase properties of these networks for developing polymers with high thermal stability and low coefficients of thermal expansion (CTE). Curing was carried out either within the nematic mesophase or the isotropic phase of the prepolymers. Transition temperatures associated with the mesophase were observed to change after curing under these two sets of conditions. The networks with the highest crosslink density were found to exhibit the lowest CTE values. Crosslinking of these thermosets was also carried out in the presence of a 13.5 Tesla magnetic field to determine the effect of orienting fields on the curing of the LC network. Orientation parameters as measured by wide angle x-ray diffraction were as high as 0.6. Values of the coefficient of thermal expansion as low as 15 ppm were achieved in the aligned direction. Of the two resin types, those with the triazine crosslinks had the lowest thermal expansion coefficient. Other thermal properties of these networks will be discussed.

Fabrication and Properties of W-SiCP/Cu Composites by Hot Pressing Sintering

2016 ◽  
Vol 697 ◽  
pp. 207-210
Author(s):  
Lian Meng Zhang ◽  
Yao Liu ◽  
Cheng Cheng Zhang ◽  
Guo Qiang Luo ◽  
Huang Liu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Hot Press ◽  
X Ray Diffraction ◽  
Ternary Composite ◽  
Hot Pressing Sintering ◽  
Hot Press Sintering ◽  
Structural Characterizations

Abstract. A new ternary composite of W-SiCP/Cu(40vol%) was designed and prepared by low-temperature hot-press sintering. The micro-structural characterizations were evaluated by X-ray diffraction (XRD) and scanning electron microstructure (SEM), coefficient of thermal expansion is measured. When sintered at 950°C-100MPa-2h, the relative density of the W-SiCP/Cu composites as a function of W content all exceeded 97%. Due to the plastic deformation of Cu, higher densification W-SiCP/Cu(40vol%) composites can be achieved at a relatively low temperature. The composites are characterized by the relatively low coefficient of thermal expansion, bending strength and hardness. The values of thermal expansion indicate that thermal expansion can be precisely controlled by adding SiC particles.

Evaluation of Coefficient of Thermal Expansion of Zirconium by Using Dilatometer & Ansys

2018 ◽  
Vol 1148 ◽  
pp. 128-135
Author(s):  
Repalle Jithendra Kumar ◽  
B.V.S. Raghu Vamsi ◽  
T. Siva Krishna ◽  
D. Tarun ◽  
M. Kamal Tej
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
Thermal Properties ◽  
Nuclear Reactors ◽  
Coefficient Of Thermal Expansion ◽  
Zirconium Alloys ◽  
Nuclear Technology ◽  
High Corrosion Resistance ◽  
Weight Percentage ◽  
Water Reactors

Zirconium alloys are solid solutions of zirconium or other metals. Zirconium has very low absorption cross-section of thermal neutrons. Zirconium has high corrosion resistance, ductility and hardness. Zirconium is mainly used as a good refractory metal. Zirconium can be manufactured by using standard fabrication techniques. In the present scenario zirconium alloys are used in water reactors for the cladding of fuel rods in nuclear reactors in nuclear technology. We use the composition of zirconium alloys as more than 94.5 weight percentage of zirconium and less than 2.45 weight percentage of copper which are added to improve mechanical, thermal properties and corrosion resistance. This paper first focuses on the study of thermal properties of Zirconium. And this particularly concentrated on variation of Coefficient of Thermal Expansion by varying temperatures by using Dilatometer and as well as ANSYS

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