Some recent developments in high-strength glasses and ceramics

1964 ◽  
Vol 282 (1388) ◽  
pp. 52-56
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Glass Ceramics ◽  
High Strength ◽  
Fine Grained ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Recent Developments ◽  
Expansion Coefficients ◽  
Mechanical Strengths

Two areas of development in the field of glasses and ceramics have produced new materials with unusual combinations of properties. Glass-ceramics are melted and formed as glasses by conventional glass-forming techniques, but by a subsequent heat treatment, they are converted to fine-grained crystalline structures with new and useful combinations of properties. Products with thermal expansion coefficients approaching zero and flexural strengths ranging from 10 000 to 50 000 Lb./in. 2 have been made though not all combinations of low thermal expansion coefficients and high mechanical strengths are possible. The second area of development is in so-called Chemcor glasses. Such glass products can be preferentially pre-stressed by chemical means so as to produce an outer layer with high compressive stress and a bending strength in the finished product up to 100 000 Lb/in. 2 .

Thermal Expansion of SrZr4-xTix(PO4)6 Ceramics

2018 ◽  
Vol 281 ◽  
pp. 169-174
Author(s):  
Yang Wang ◽  
Yuan Yuan Song ◽  
Yuan Yuan Zhou ◽  
Lu Ping Yang ◽  
Fu Tian Liu
Keyword(s):  
Thermal Expansion ◽  
Relative Density ◽  
Thermophysical Properties ◽  
Sintering Temperature ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
High Relative Density ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Low thermal expansion ceramics have been widely applied in multiple fields. In this paper, a series of low thermal expansion ceramics SrZr4-xTix(PO4)6 was prepared and characterized. The SrZr4-xTix(PO4)6 ceramics could be well sintered in the temperature range of 1400~1500 °C. The effect of the addition of Ti substituting Zr and the sintering temperature was studied. The Ceramic with x =0.1 sintered at 1450 °C, the SrZr4-xTix(PO4)6 had a high relative density. The thermal expansion coefficients were about 3.301×10-6 °C-1. It was demonstrated that the microstructure of the SrZr4-xTix(PO4)6 could be altered by adding varying amount of Ti to tailor the thermophysical properties of the material.

Properties of ZrO2/Glass-Ceramics Composite

2007 ◽  
Vol 280-283 ◽  
pp. 995-998
Author(s):  
Y.M. Zhu ◽  
Xia Wan Wu ◽  
Zhi Hong Li
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Glass Powder ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Glass Content ◽  
Thermal Expansion Coefficients ◽  
Lower Thermal Expansion ◽  
Expansion Coefficients

In order to reduce the raw materials cost, lower the sintering temperature of 3Y-TZP optical fiber ferrules, the 3Y-TZP/ LAS glass ceramics composites were prepared and their properties were investigated in this paper. The results showed that the sintering temperatures and thermal expansion coefficients of the 3Y-TZP/LAS glass ceramics composites were lowered with the increase of glass content. The flexural strength of the composites were decreased with the increase of glass content, but the flexural strength of the composite with 15% weight glass was higher than 400MPa. The LAS glass powder added into the composites was crystallized and b-spodumene s.s was precipitated. during sintering. The b-spodumene s.s. having lower thermal expansion coefficient and higher strength was beneficial to reduce thermal expansion coefficients and keep higher strengths of the composites .

Ultrasonic Torsional Welding of Metal/Glass Ceramics Joints

2019 ◽  
Vol 809 ◽  
pp. 237-244
Author(s):  
Andreas Gester ◽  
Guntram Wagner
Keyword(s):  
Mechanical Characterization ◽  
Glass Ceramics ◽  
Dissimilar Materials ◽  
High Strength ◽  
Tensile Shear ◽  
Shear Tests ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Solid State Joining ◽  
Welding Technique

Ultrasonic welding is a suitable solid-state joining technique for producing high strength joints of similar or dissimilar materials, even of material combinations that were previously considered as not weldable. Several varieties of transmitting the ultrasound into the joining partners exist whereas the investigated torsional welding principle utilizes a ring shaped sonotrode for transmitting ultrasonic vibrations tangentially to the welding force into the workpiece. Due to the specific sonotrode geometry ultrasonic torsional welding is a remarkably gentle welding technique, allowing to join even most sensitive components e.g. sensors or brittle elements. Nevertheless, ultrasonic torsional welded joints show high tensile strengths and helium-tightness. Current investigations focus on the realization of metal/glass ceramics joints. In this project two metals with different thermal expansion coefficients have been utilized as the metal joining partner. The glass joining partner was the commercially available Li2O-Al2O3-SiO2 CERAN. For examining the microstructure light as well as scanning electron microscopy have been performed. Additionally, mechanical characterization has been carried out through tensile shear tests.

Studies of Microdefects, Thermal Expansion and Magnetic Properties of Fe-Ni-Co Invar Alloys

2017 ◽  
Vol 373 ◽  
pp. 146-149
Author(s):  
Wen Deng ◽  
Li Xia Li ◽  
Shou Lei Xu ◽  
Wen Chun Zhang ◽  
Yu Yang Huang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Large Change ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Invar Alloys ◽  
Low Thermal Expansion ◽  
Expansion Coefficients ◽  
Fcc Phase ◽  
Bcc Phase

The microdefects, the thermal expansion coefficients and the magnetization -temperature curves of the Fe64Ni36-xCox (x=1~10) were characterized by means of positron lifetime, X-ray diffraction, Michelson's interferometer and VSM modular on PPMS, respectively. The Fe64Ni30Co6 alloy is a mixture of BCC and FCC structures. With the Co content increasing in Fe64Ni36-xCox alloys, the BCC phase increases, while the FCC phase decreases. In comparison with other Fe64Ni36-xCox alloys, the Fe64Ni31Co5 alloy has a rather high magnetization at temperature lower than Tc, a relatively large change of the magnetization with the temperature near Tc, and a rather low thermal expansion coefficient.

Properties and crystallization of Li2O–CaO–Al2O3–SiO2–TiO2glasses

1993 ◽  
Vol 8 (4) ◽  
pp. 890-898 ◽  
Author(s):  
Moo-Chin Wang ◽  
Min-Hsiung Hon
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Diffraction Analysis ◽  
Crystalline Phase ◽  
Glass Ceramics ◽  
Weight Percent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The addition of CaO to Li2O–Al2O3–SiO2–TiO2(LAST), forming the Li2O–CaO–Al2O3–SiO2–TiO2(LCAST) system, is used in the preparation of low themal expansion coefficient glass-ceramics. By a progressive weight percent substitution of CaO for SiO2, at constant ratios of concentration of Li2O, Al2O3, and TiO2, a number of properties of these glasses have been studied. The results indicated that these thermal properties increased progressively with increasing CaO concentration. X-ray diffraction analysis was utilized to identify the crystalline phase in glass-ceramics of the Li2O–CaO–Al2O3–SiO2-TiO2system. Thed-spacings of the major crystallites were precisely measured and fitted with those of β-spodumene. The minor crystalline phase of titanite, CaO · TiO2· SiO2, was also present. The average thermal expansion coefficients from 25 to 700 °C were 3.50 × 10−6/°C, 3.81 × 10−6/°C, and 3.91 × 10−6/°C for samples A, B, and C, respectively.

Nanoscale Chemical Mapping of Semiconductor Devices and Materials via PiFM

2018 ◽  
Author(s):  
Sung Park ◽  
Derek Nowak ◽  
Tom Albrecht
Keyword(s):  
Thermal Expansion ◽  
Self Assembly ◽  
Chemical Mapping ◽  
Force Microscopy ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Semiconductor Compounds ◽  
High Resolution Images ◽  
Expansion Coefficients ◽  
Microscopy Techniques

Abstract Nanoscale microscopy is an important technique in analyzing current semiconductor processes and devices. Many of the current microscopy techniques can render high resolution images of morphology and, in some cases, elemental information. However, techniques are still needed to give definitive nanoscale mapping of compound materials utilized in semiconductor processes such as Si3N4, SiO2, SiGe, and low-k materials. Photo-induced force microscopy (PiFM) combines IR spectroscopy with atomic force microscopy (AFM) to provide concurrent information on topography and chemical mapping. PiFM measures the attractive dipole-dipole photo-response between the tip and the sample and does not rely on repulsive force arising from absorption-based sample expansion. As such, PiFM works well with many of the inorganic semiconductor compounds (with low thermal expansion coefficients) as well as organic materials (with high thermal expansion coefficients) [1]. In this study, various examples of nanoscale chemical mapping of semiconductor samples (surfaces processed via directed self-assembly (DSA), strain in SiGe/SiO2 structure, photoresist, etc.) will be presented, all demonstrating ~ 10 nm spatial resolution

scholarly journals Epoxy molding compounds with low thermal expansion coefficients.

1989 ◽  
Vol 46 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Masatsugu OGATA ◽  
Hiroshi HOZOJI ◽  
Syunichi NUMATA ◽  
Noriyuki KINJO ◽  
Osamu HORIE
Keyword(s):  
Thermal Expansion ◽  
Molding Compounds ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Highly transparent and flexible silica/cellulose films with a low coefficient of thermal expansion

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 52349-52356 ◽  
Author(s):  
Yuehan Wu ◽  
Xingzhong Zhang ◽  
Bin Li ◽  
Shilin Liu
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Cellulose Films ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Expansion Coefficients

Highly transparent and flexible silica/cellulose films with low thermal expansion coefficients have been prepared by the in situ synthesis of silica in cellulose scaffolds using Na2SiO3 as a precursor.

Preparation and Properties Study of Cu-MoSi2 Composites

2007 ◽  
Vol 534-536 ◽  
pp. 581-584 ◽  
Author(s):  
Xiaoou Yi ◽  
Wei Hao Xiong ◽  
Jian Li
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Mechanical And Thermal Properties ◽  
Matrix Composites ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Powder Metallurgy Process ◽  
Expansion Coefficients ◽  
Metallurgy Process

The particulate dispersive strengthened Cu-MoSi2 composites were prepared by a powder metallurgy process with aim to develop novel copper based composites of reasonable strength, high thermal conductivity and low thermal expansion coefficients. Compacted samples were sintered to over 90% of theoretical density. Microstructure of the composites was investigated by SEM while mechanical properties such as tensile strength, elongation and thermal properties such as thermal conductivity and thermal expansion coefficient (CTE) of the composites were examined as a function of the MoSi2 content and the process of fabrication. A comparative analysis of the mechanical and thermal properties of various Cu-matrix composites currently in use was given and the strengthening mechanisms for the Cu-MoSi2 composites were discussed.

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