Sintering of Cordierite–borosilicate Glass Composites

2000 ◽  
Vol 15 (8) ◽  
pp. 1759-1765 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Jui-Kai Wang
Keyword(s):  
Thermal Expansion ◽  
Borosilicate Glass ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
High Viscosity ◽  
Glass Composites ◽  
Density Reduction ◽  
Low Viscosity ◽  
The Difference ◽  
Typical Range

The sintering and properties of cordierite–borosilicate glass composites were investigated. For the composites with ≥35% low-viscosity glass, the sintered densities decreased with the increasing sintering temperature above 850 °C. No crystallization of the glass was found. For the composites with 50–90 wt% high-viscosity glass, the sintered densities remained nearly constant (>95%) in a wide sintering temperature range. However, cristobalite crystallized from the glass phase, resulting in an undesirably high coefficient of thermal expansion. Presintering processing and a lower heating rate improved the densification of the composites with low-viscosity glass while limiting that of the composites with high-viscosity glass. This result is explained by the difference in crystallizability between these two glasses. As low- and high-viscosity glass powders were simultaneously added, the density reduction was reduced and the coefficient of thermal expansion was closer to that of Si because of the absence of cristobalite phase. The dielectric constant of all the composites was in the typical range of 4.9–5.7 at 1 MHz.

Sintering and properties of Li2O · Al2O3 · 4SiO2-borosilicate glass composites

1996 ◽  
Vol 11 (10) ◽  
pp. 2518-2527 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Ching-Tang Wang
Keyword(s):  
Dielectric Constant ◽  
Loss Tangent ◽  
Borosilicate Glass ◽  
High Viscosity ◽  
Silica Content ◽  
Glass Crystallization ◽  
Major Phase ◽  
Glass Composites ◽  
Density Reduction ◽  
Low Viscosity

Sintering, glass crystallization, microstructure, and the resulting properties of spodumene-borosilicate glass composites were investigated. Densities >90% could be obtained for samples sintered below 1000 °C. Samples that contained more low-viscosity glass densified at lower temperatures, and significant density reduction was observed at higher temperatures. Samples that contained high-viscosity glass densified only at higher temperatures. When glasses of different viscosity were added, the densification of the composites was improved. There was interdiffusion between spodumene and glass. Cristobalite crystallized from the pure glasses. Addition of spodumene changed the major phase crystallized to anorthite or α-quartz as a result of dissolution of spodumene into glass. Composites that contained glass of higher silica content showed more crystallization. As sintering temperatures increased, the amount of crystallization decreased, due to dissolution of glass into spodumene. The spodumene particles showed angular shape with smooth and straight sides. The spodumene-glass composites showed a dielectric constant in the range of 5–6, a loss tangent generally <1%, and a CTE value in the range of 2–5.6 × 10–6 K–1. Codoping of glasses with different viscosity effectively improved the densification and properties of the composites.

Microstructure and Properties of Calcium Borosilicate and Borosilicate Glass-Ceramic Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1422-1425 ◽  
Author(s):  
An Guo Lu ◽  
Tai Qiu
Keyword(s):  
Borosilicate Glass ◽  
Glass Ceramic ◽  
Mass Fraction ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Ceramic Composites ◽  
Glass Content ◽  
Microstructure And Properties ◽  
Calcium Borosilicate ◽  
Crystal Phases

Calcium borosilicate (CaO-B2O3-SiO2, CBS) glass based glass-ceramic composites were prepared by introducing borosilicate glass. The effects of borosilicate glass and firing temperature on the microstructure and properties of the glass-ceramic composites were investigated. The results showed that the composites containing 0~40% (in mass fraction, the same below) borosilicate glass can be sintered at 850°C. The dielectric constant (εr) decreases with the increase of borosilicate glass content and can be adjusted in the range of 5.6~6.6. The coefficient of thermal expansion (CTE) increases with the increase of borosilicate glass content. Increasing sintering temperature favors the precipitations of crystal phases, which have lower εr than CBS glass, resulting in the decrease of εr for the composites.

Bilayer graded Al/B4C/rice husk ash composite: Wettability behavior, thermo-mechanical, and electrical properties

2018 ◽  
Vol 52 (27) ◽  
pp. 3745-3758 ◽  
Author(s):  
Amin Bahrami ◽  
Niloofar Soltani ◽  
Martin I Pech-Canul ◽  
Shaghayegh Soltani ◽  
Luis A González ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Aluminum Alloys ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Expansion Coefficients ◽  
One Step ◽  
The Difference

In this study, wettability behavior of B4C substrate as well as B4C/crystalline rice husk ash and B4C/amorphous rice husk ash substrates with two aluminum alloys were studied. The electrical resistivity, thermal expansion coefficients, and thermal diffusivity of bilayer Al/B4C/rice husk ash composite fabricated by one-step pressureless infiltration were measured and the obtained data were systemically analyzed using the Taguchi method and analysis of variance. Boron carbide substrates after addition of amorphous or crystalline rice husk ash display good wettability with molten aluminum alloys. The results show that, electrical resistivity of Al/B4C/rice husk ash composites is mainly influenced by initial preform porosity, while the coefficient of thermal expansion of composites is determined by the chemical composition of infiltrated alloys. The measured values for coefficient of thermal expansion (10.5 × 10−6/℃) and electrical resistivity (0.60 × 10−5 Ω.m) of Al/B4C/rice husk ash composites, fabricated according to analysis of variance's optimal conditions are in good agreement with those of the projected values (11.02 × 10−6/℃ and 0.65 × 10−5 Ω.m, respectively). The difference between the corresponding values obtained from verification tests and projected values, for electrical resistivity and coefficient of thermal expansion are less than 5%. Finally, as a material selection approach, the strengths and weaknesses of the composites have been graphed in the form of radar diagrams.

Modification of Porous Cordierite Ceramic

2016 ◽  
Vol 721 ◽  
pp. 322-326
Author(s):  
Ruta Švinka ◽  
Visvaldis Svinka ◽  
Julija Bobrovik
Keyword(s):  
Compressive Strength ◽  
Thermal Expansion ◽  
Large Scale ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Slip Casting ◽  
Concentrated Suspension ◽  
Cordierite Ceramic ◽  
Silica Additive ◽  
Porous Cordierite

Highly porous cordierite ceramic by using of talcum, kaolinite and γ-alumina was obtained by method of slip casting of concentrated suspension. Additives of amorphous silica and non-stabilized zirconia in the amount of 5 wt% were used. Sintering temperature of dried samples was in range of 1250 – 1450°C. All the samples contain crystalline phases of cordierite, mullite and corundum but, depending on the additives, as a result of sintering in addition forms spinel, cristobalite or zircon (ZrSiO4). Porosity of obtained materials changes in large scale from 42 to 59 per cent; it is influenced by both sintering temperature and composition. Compressive strength increases with the addition of zirconia. In comparison, compressive strength of samples without additives or with silica additive does not exceed 3.5 MPa. The increase of coefficient of thermal expansion depends both on the composition and sintering temperature. ZrO2 additive increases the coefficient of thermal expansion considerably.

Coefficient of Thermal Expansion of Polymer Concrete with Different Polymeric Binders

2015 ◽  
Vol 1129 ◽  
pp. 139-144
Author(s):  
Kyu Seok Yeon ◽  
Kwan Kyu Kim ◽  
Chul Young Kim ◽  
Jae Heum Yeon
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Polymer Concrete ◽  
Extensive Literature ◽  
Polymeric Binder ◽  
Factors Affecting ◽  
Concrete Members ◽  
Different Types ◽  
Polymeric Binders ◽  
Typical Range

The coefficient of thermal expansion (CTE) is one of the material factors affecting the behavior of concrete structures. This study reports the typical range of CTE for polymer concrete with different types of polymeric binder based on extensive literature surveys. The results revealed the CTE of polymer concrete generally fell between 12.5 and 28.6 x 10-6/°C, which is about twice or three times higher than that of ordinary cement concrete, because the CTE of polymeric binder is much larger than that of cementitious binders. The findings of this study will provide useful information for the design and analysis of polymer concrete members and repair components.

scholarly journals Thermal analysis of metal-ceramic bonding using finite element method

2014 ◽  
Vol 3 (2) ◽  
pp. 216 ◽  
Author(s):  
S. Gopinath ◽  
R Sabarish ◽  
R. Sasidharan
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Bonding Strength ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Processing Temperature ◽  
Element Analysis ◽  
Metal Ceramic ◽  
The Difference

This paper reports a finite element study of effect of bonding strength between metal and ceramic. The bonding strength is evaluated with different processing temperature and holding time. The difference between the coefficients of linear thermal expansion (CTEs) of the metal and ceramic induces thermal stress at the interface. The mismatch thermal stress at the interface region plays an important role in improving bonding strength. Hence, it is essential to evaluate the interface bonding in metal-ceramics joints. The Al/SiC bonding was modeled and analyzed using finite element analysis in ANSYS (v.10). Keywords: Bonding Strength, Coefficient of Thermal Expansion, Thermal Stress, Interface, Al/Sic, FEA.

Effects of Hybrid Structures on the Stress Reduction and Thermal Properties of Joints in Electronics Devices

2016 ◽  
Vol 879 ◽  
pp. 1258-1264
Author(s):  
Michiya Matsushima ◽  
Noriyasu Nakashima ◽  
Satoshi Nishioka ◽  
Shinji Fukumoto ◽  
Kozo Fujimoto
Keyword(s):  
Thermal Expansion ◽  
Epoxy Resin ◽  
Stress Reduction ◽  
Analytical Study ◽  
Coefficient Of Thermal Expansion ◽  
Conductive Adhesives ◽  
Silicon Chips ◽  
Composite Joint ◽  
The Difference ◽  
Reduction Effect

Electronics devices consist of silicon chips, copper leads, resin or ceramics substrates and which are jointed to each other with solder, conductive adhesive or other materials. Each coefficient of thermal expansion is different and it causes strain concentration and cracks. The solder easily deformed by the difference of the thermal expansion and it relieved the stress on the devices however the epoxy resin of the conductive adhesives are harder. So we suggested the composed joint including the relaxation layers of low elastic material. The shear strength and elongation of the epoxy resin joint, silicone rubber joint and the composite joint of the two materials were investigated. The analytical study was carried out to clarify the stress reduction effect of the design of the relaxation layer in the composite joints. The parameters such as the width, height, pitch and the distance of the relaxation layer from the joint edge are investigated. The high relaxation layer close to the joint edge effectively reduced the stress of the joint. The stress reduction effect appeared in the different pitch of the layers.

The Effect of Sintering Temperature on Physical Properties of Leucite Ceramics

2019 ◽  
Vol 891 ◽  
pp. 214-218
Author(s):  
Jirasak Tharajak ◽  
Noppakun Sanpo
Keyword(s):  
Thermal Expansion ◽  
Research Study ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Sol Gel ◽  
Physical Property ◽  
Dental Ceramics ◽  
Ceramic Particles ◽  
Sol Gel Process

Leucite has been widely used as a constituent of dental ceramics to modify the coefficient of thermal expansion. This is most important where the ceramic is to be fused or baked onto metal. However, its physical property was unpredictable since it was sensitive to several parameters such as sintering temperature and concentration of raw materials. In this research study, leucite ceramic particles were synthesized by in-house sol-gel process. The morphology and size of our synthesized leucite particles were analyzed by SEM, vicker hardness and XRD, respectively. It was revealed that the sintering temperature played the important role on several properties of leucite ceramic particles.

Dielectric Properties of LTCC System of Al2O3 and Borosilicate Glass

2007 ◽  
Vol 336-338 ◽  
pp. 783-785 ◽  
Author(s):  
Yang Liu ◽  
Yan Wang ◽  
Ju Sheng Ma
Keyword(s):  
Dielectric Constant ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Dielectric Properties ◽  
Borosilicate Glass ◽  
Coefficient Of Thermal Expansion ◽  
Al2o3 Content ◽  
Powder Size ◽  
Al2o3 Powder ◽  
Low Permittivity

In this paper, three types of Al2O3 powders with different sizes (1.6μm, 0.7μm, and 0.3μm) were used in a LTCC system of Al2O3 and borosilicate glass (BSG). Al2O3 and BSG are selected on account of their coefficient of thermal expansion (CTE) similar to silicon, which can reduce thermal stress. It was found that the dielectric constant, ε, of substrates drops with the decrease of Al2O3 powder size. ε increases with the increase of Al2O3 content for the sample with 1.6 μm Al2O3 powder, but decreases with the increase of Al2O3 content for the samples with 0.7 μm and 0.3 μm Al2O3 powders. SEM observations revealed that more pores with low permittivity appeared for the samples with smaller Al2O3 powders, resulting in the drop of dielectric constant of the sample finally.

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