The Coefficient of Thermal Expansion of a Super Invar-Ta16W18O94 Composite

1986 ◽  
Vol 108 (3) ◽  
pp. 270-274 ◽  
Author(s):  
C. N. Chu ◽  
N. Saka ◽  
N. P. Suh
Keyword(s):  
Thermal Expansion ◽  
Powder Metallurgy ◽  
Coefficient Of Thermal Expansion ◽  
Ceramic Composites ◽  
Volume Percent ◽  
Temperature Range ◽  
Metal Ceramic

The coefficient of thermal expansion (CTE) of a hot pressed Ta16W18O94 which was produced from Ta2O5 and WO3 powders was found to be −1.52×10−6 K−1 in the temperature range 180–330 K. Using the Ta16W18O94 and Super Invar powders, 50:50 volume percent metal-ceramic composites were made by the powder metallurgy techniques. When the mixture of constituent powders was hot pressed at 1123 K for 10 minutes, a CTE of 1.1 × 10−6 K−1 was obtained in the temperature range 140–420 K.

Magneto-Optical Properties of Ni-MgO and Co-MgO Nanocomposite Films Obtained by Partial Reduction Reactions

1997 ◽  
Vol 475 ◽  
Author(s):  
J. A. Smith ◽  
P. Limthongkul ◽  
L. Hartsuyker ◽  
S. Y. Kim ◽  
S. L. Sass
Keyword(s):  
Thermal Expansion ◽  
Optical Properties ◽  
Magnetic Anisotropy ◽  
Coefficient Of Thermal Expansion ◽  
Sol Gel ◽  
Optical Measurements ◽  
Nanocomposite Films ◽  
Two Phase ◽  
Varying Coefficients ◽  
Metal Ceramic

ABSTRACTA new processing technique was developed to synthesize metal-ceramic films containing nano-sized Ni or Co particles embedded in a MgO matrix. Sol-gel solutions were spun on different substrates with varying coefficients of thermal expansion, oxidized by heating in air and reduced to form a metal-ceramic two phase mixture. This method allows the generation of perpendicular magnetic anisotropy by use of residual stresses arising from a coefficient of thermal expansion difference between the film and substrate. Magneto-optical measurements show that the films can have relatively large Kerr and Faraday rotations, and that the metal particles have sufficient vertical magnetic anisotropy to support perpendicular magnetization. The magneto-optical properties of the films are related to the metal particle size, film thickness and substrate choice.

Fabrication and Characterization of Low Thermal Expansion Cordierite/Spodumene/Mullite Composite Ceramic for Cookware

2018 ◽  
Vol 766 ◽  
pp. 276-281
Author(s):  
Pranee Junlar ◽  
Thanakorn Wasanapiarnpong ◽  
Lada Punsukmtana ◽  
Noppasint Jiraborvornpongsa
Keyword(s):  
Thermal Expansion ◽  
Water Absorption ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Modulus Of Rupture ◽  
Mullite Phase ◽  
Low Thermal Expansion

Ceramic cookware can be taken a direct flame or stove top for the duration without damage. The selected materials must have low thermal expansion coefficient, high strength, low water absorption and high thermal shock resistance, reasonable in cost and easy to be produced. Cordierite and spodumene composite has been interested for ceramic cookware due to their fitted properties. In previous work, study in the cordierite-spodumene composite with low thermal expansion coefficient of 2.60 x 10-6 /°C when sintered at 1250 oC with a ratio of spodumene 60 wt% and cordierite 40 wt% can withstand the pot shape samples. However, the sample showed relatively high water absorption and low strength which was not appropriate for using in this application. In this research, mullite is added in the formula to improve strength and densification of ceramic composites. Spodumene, ball clay, calcined talc and calcined alumina are used as starting raw materials and formed by slip casting. All samples are sintered in a temperature range from 1250-1275 °C in an electric furnace. Water absorption and bulk density were tested by Archimedes method, modulus of rupture was tested by the three-point bending method, microstructure were investigated by SEM and the coefficient of thermal expansion was measured by dilatometer. It was found that the mullite phase was investigated when adding mullite more than 30 wt% in cordierite-spodumene composite.

scholarly journals Тепловое расширение кристаллов Pb-=SUB=-1-x-=/SUB=-Cd-=SUB=-x-=/SUB=-Te

2021 ◽  
Vol 55 (12) ◽  
pp. 1216
Author(s):  
М.К. Шаров
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Solid Solutions ◽  
Coefficient Of Thermal Expansion ◽  
Cadmium Content ◽  
Lattice Period ◽  
Linear Coefficient ◽  
X Ray ◽  
Temperature Range

The values of the lattice period and the linear coefficient of thermal expansion (alfa) of Pb1-xCdxTe solid solutions are determined depending on the cadmium content and temperature using high-temperature X-ray diffractometry. Аn increase in the concentration of cadmium in Pb1-xCdxTe in the range x = 0.02–0.08 leads to a significant increase in the linear coefficient of thermal expansion. A change in temperature range T = 293–673 K leads to decrease in the linear coefficient of thermal expansion. Besides, an increase in temperature does not affect the value alfa of the undoped PbTe in the indicated temperature range.

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.

Analyzing Hysteresis and Thermal Expansion Coefficient of M40/AZ91D during Thermal Cycling

2017 ◽  
Vol 898 ◽  
pp. 890-897
Author(s):  
Mei Hui Song ◽  
Yu Zhang ◽  
Yan Chun Li ◽  
Guo Qin Chen ◽  
Zi Yang Xiu
Keyword(s):  
Thermal Expansion ◽  
Thermal Cycling ◽  
Temperature Change ◽  
Residual Strain ◽  
Coefficient Of Thermal Expansion ◽  
Internal Heat ◽  
Impregnation Method ◽  
Change Rate ◽  
Temperature Range ◽  
Temperature Change Rate

In this work, AZ91D composite reinforced with M40 fiber was prepared by pressure impregnation method. Expansion behaviors of M40/AZ91D composite were studied with thermal expansion instrument in 25-150 °C and 25-150 °C temperature ranges of internal heat circulation, and then analyzed the influence law of hysteresis, residual strain and coefficient of thermal expansion (CTE) by different temperature change rate. The results revealed that residual stress and strain in process of pressure impregnation would lead to strain hysteresis and residual strain of composite in thermal cycling. At the same time, the CTE of the composites decreased with the increase of cycle times. Residual strain of the composite went up with the rise of temperature changed rate of the thermal cycling and CTE decreased with temperature change rate ascending in the 25-150°C temperature range. The CTE of the composites decreased with the increase of temperature during the heating process, which cut down with the increase of temperature in process of heating and cooling in the 25-495°C temperature range.

scholarly journals A comprehensive study of Al-Cu-Mg system reinforced with nano-ZrO2 particles synthesized by powder metallurgy technique

2021 ◽  
Author(s):  
Waheed S. AbuShanab ◽  
Essam B. Moustafa ◽  
E. Ghandourah ◽  
Mohammed Taha
Keyword(s):  
Particle Size ◽  
Thermal Expansion ◽  
Powder Metallurgy ◽  
Coefficient Of Thermal Expansion ◽  
Industrial Applications ◽  
Powder Metallurgy Technique ◽  
Wear And Corrosion ◽  
Particle Size Analyzer ◽  
Matrix Nanocomposites ◽  
Comprehensive Study

Abstract Recently, increasing attention has been devoted to improving the various properties of aluminum alloys such as strength, elastic modulus, and coefficient of thermal expansion (CTE) as well as wear and corrosion by adding different percentages of ceramics for use in various industrial applications. In this sense, powder metallurgy technique has been used to fabricate Al-4.2 wt.% Cu-1.6 wt.% Mg matrix nanocomposites reinforced by different weight percentages of nano-ZrO2 particles. The microstructure and particle size distributions of the prepared powders were examined by SEM, TEM technique and diffraction particle size analyzer. The prepared powders were compacted and sintered in argon to obtain good sinterability. The physical, elastic and mechanical properties of the sintered nanocomposites were measured. Furthermore, thermal expansion, wear and corrosion behavior were also studied. The results showed that the decrease in the particle sizes of the Al-Cu-Mg alloy by adding ZrO2 nanoparticles up to 47.8 nm for the composite containing 16 wt.% ZrO2. With increasing the sintering temperature to 570 °C, the densification of nanocomposites was clearly enhanced. Also, the coefficient of thermal expansion and wear rate were remarkably decreases about 28 and 37.5 % with adding after adding 16 wt. % ZrO2. Moreover, microhardness yield, strength and Young’s modulus were enhanced to 161, 145 and 64%, respectively after adding 16 wt.% ZrO2. In addition, increasing the exposure time was responsible for decreasing the corrosion rate for the same sample.

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