β-Spodumene Glass-Ceramic with Anomalous Low Thermal Expansion

2008 ◽  
Vol 39-40 ◽  
pp. 381-386 ◽  
Author(s):  
Akihiko Sakamoto ◽  
Yusuke Himei ◽  
Yoshio Hashibe
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Ceramic Material ◽  
Glass Ceramic ◽  
Silica Glass ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
New Method ◽  
Low Thermal Expansion ◽  
Natural Stones

To survey new method for controlling thermal expansion of glass-ceramic material, we studied the coefficient of thermal expansion (CTE) and the microstructure of β-spodumene glass-ceramics. We found that the CTE of the β-spodumene glass-ceramics is remarkably reduced by introducing interstices at the boundary between the crystalline and glass phases. Despite its relatively low crystallinity (45vol%), a newly developed glass-ceramic showed an anomalous low thermal expansion of 7x10-7 /oC, which compares to that of silica glass. The mechanical strength of this glass-ceramic was at the same level as that of natural stones: marble and granite.

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.

scholarly journals Augite-anorthite glass-ceramics from residues of basalt quarry and ceramic wastes

2015 ◽  
Vol 9 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Gamal Khater ◽  
Safiah Abu ◽  
Esmat Hamzawy
Keyword(s):  
Thermal Expansion ◽  
Glass Ceramic ◽  
Crystallization Process ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Ceramic Samples ◽  
Heat Treated ◽  
Prepared Glass ◽  
Higher Temperature ◽  
Dominant Phase

Dark brown glasses were prepared from residues of basalt quarries and wastes of ceramic factories. Addition of CaF2, Cr2O3 and their mixture CaF2-Cr2O3 were used as nucleation catalysts. Generally, structures with augite and anorthite as major phases and small amount of magnetite and olivine phases were developed through the crystallization process. In the samples heat treated at 900?C the dominant phase is augite, whereas the content of anorthite usually overcomes the augite at higher temperature (1100?C). Fine to medium homogenous microstructures were detected in the prepared glass-ceramic samples. The coefficient of thermal expansion and microhardnessmeasurements of the glass-ceramic samples were from 6.16?10-6 to 8.96?10-6?C-1 (in the 20-500?C) and 5.58 to 7.16GP, respectively.

BaO-Al2O3-SiO2-B2O3 Glass-Ceramic SOFCs Sealant: Effect of ZnO Additive

2017 ◽  
Vol 751 ◽  
pp. 455-460 ◽  
Author(s):  
Nattapol Laorodphan ◽  
Jiratchaya Ayawanna
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Solid Oxide Fuel Cells ◽  
Glass Ceramic ◽  
Coefficient Of Thermal Expansion ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
X Ray ◽  
Barium Aluminosilicate ◽  
Xrd Patterns

The crystallization of planar solid oxide fuel cells (SOFCs) sealant glasses in the systems BaO-Al2O3-SiO2-B2O3 (BaBS) and BaO-Al2O3-SiO2-B2O3-ZnO (BaBS-Zn) was investigated via both X-ray diffractometer and scanning electron microscopy with energy dispersive spectroscopy. The effect of nucleation heat-treatment of the BaBS glass at different temperature for 5 hours, i.e. 550 and 590 °C, on the crystallization behavior was also studied. Thermal expansion profiles of the glasses indicate that both glasses have a low sealing temperature. XRD patterns of all BaBS glass-ceramics, devitrified at 800 °C for 30 hours, show that Ba2Si3O8, BaAl2Si2O8, Ba3B2O6 and some unknown crystalline phases were found. It was also found that crystalline size of unknown barium aluminosilicate with low silicon content depends on the nucleation heat-treatment temperature. For the ZnO-containing glass, ZnO reduces the coefficient of thermal expansion value of glass and causes the devitrification of large needle-like barium zinc silicate phases. The crack at the YSZ/BaBS-Zn glass-ceramic interface was also observed. Two barium silicate phases, which are BaZnSiO4 and BaZn2Si2O7 were devitrified in ZnO-containing glass-ceramic.

scholarly journals Strengthening of the Fe-Ni Invar Alloy Through Chromium

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1297 ◽  
Author(s):  
Qingshuang Sui ◽  
Jun He ◽  
Xin Zhang ◽  
Zhonghua Sun ◽  
Yunfei Zhang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Aging Time ◽  
Power Transmission ◽  
Coefficient Of Thermal Expansion ◽  
High Strength ◽  
Invar Alloy ◽  
Invar Alloys ◽  
Low Thermal Expansion ◽  
Cost Efficient

Invar alloys with both high strength and low thermal expansion are urgently needed in fields such as overhead power transmission, aero-molds, and so on. In this paper, Cr was introduced as a cost-efficient alloying element into the Fe-36Ni binary invar alloy to increase its mechanical strength. Our results confirmed that fine Cr7C3 precipitants, together with some Fe3C, in the invar alloy aged at 425 °C could be obtained with a short aging time. Those precipitants then grew and aggregated at grain or sub-grain boundaries with an increase in aging time. Simultaneously, mechanical strength and coefficient of thermal expansion (CTE) parabolically varied with the increase in aging time. The sample aged at 425 °C for 7 h presented a maximum strength of 644.4 MPa, together with a minimum coefficient of thermal expansion of 3.30 × 10−6 K−1 in the temperature range of 20–100 °C. This optimized result should be primarily attributed to the precipitation of the nanoscaled Cr7C3.

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.

scholarly journals Fabrication and Characterization of the Modified EV31-Based Metal Matrix Nanocomposites

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Structural Effect ◽  
Metal Matrix Nanocomposites ◽  
Mechanical Stirring ◽  
Specific Strength ◽  
The Matrix ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications.

Material and application study for low thermal expansion glass-ceramic CLEARCERAM series

2005 ◽  
Author(s):  
Kousuke Nakajima ◽  
Toshihide Nakajima ◽  
Nobuo Kawasaki ◽  
Yoshiyuki Owari
Keyword(s):  
Thermal Expansion ◽  
Glass Ceramic ◽  
Application Study ◽  
Low Thermal Expansion

Radiation effects on a low‐thermal‐expansion glass ceramic

1987 ◽  
Vol 62 (8) ◽  
pp. 3488-3490 ◽  
Author(s):  
T. E. Tsai ◽  
P. L. Higby ◽  
E. J. Friebele ◽  
D. L. Griscom
Keyword(s):  
Thermal Expansion ◽  
Glass Ceramic ◽  
Radiation Effects ◽  
Low Thermal Expansion

Study of the thermal stability of Zerodur glass ceramics suitable for a scanning probe microscope frame

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Ondřej Číp ◽  
Radek Šmíd ◽  
Martin Čížek ◽  
Zdeněk Buchta ◽  
Josef Lazar
Keyword(s):  
Glass Ceramic ◽  
Coefficient Of Thermal Expansion ◽  
Frequency Comb ◽  
Thermal Characteristic ◽  
Glass Ceramics ◽  
Tunable Laser ◽  
Tunable Laser Diode ◽  
Optical Mixing ◽  
Length Changes ◽  
Set Up

AbstractThe work presents measurements of the length stability of Zerodur glass ceramic with temperature change. Measurement of this thermal characteristic is necessary for determination of the optimal temperature at which the Zerodur glass ceramic has a coefficient of thermal expansion close to zero. The principle of the measurement is to monitor the length changes using an optical resonator with a cavity mirror spacer made from the Zerodur material to be studied. The resonator is placed inside a vacuum chamber with a temperature control. A tunable laser diode is locked to a certain optical mode of the resonator to monitor the optical frequency of this mode. A beat-note signal from optical mixing between the laser and a stabilized femtosecond frequency comb is detected and processed. The temperature dependence of the glass ceramics was determined and analyzed. The resolution of the length measurement of the experimental set-up is on the order of 0.1 nm.

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