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.

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.

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.

Synthesis and processing of nanocrystalline Ag–Fe–Ni for low thermal expansion–high conductivity thermal management applications

2001 ◽  
Vol 16 (2) ◽  
pp. 340-343 ◽  
Author(s):  
J. Stolk ◽  
M. Gross ◽  
D. Stolk ◽  
A. Manthiram
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Metal Ion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Nominal Composition ◽  
Two Phase ◽  
X Ray ◽  
Fine Grained ◽  
Low Thermal Expansion

Nanocrystalline Ag–Fe–Ni powders were produced by a reduction of the aqueous metal ion solutions with sodium borohydride and then converted to fine-grained silver–Invar alloys that offer attractive thermal, electrical, and mechanical properties. The samples were characterized by x-ray diffraction, scanning electron microscopy, wavelength dispersive x-ray spectrometry, thermomechanical analysis, microhardness measurements, and electrical conductivity measurements; thermal conductivity was estimated using the Wiedemann–Franz law. Sintering of a specimen with a nominal composition of 60 wt% Ag–25.6 wt% Fe–14.4 wt.% Ni led to the formation of a two-phase silver–Invar alloy with a grain size of approximately 2 μm, a hardness of 133 HK200g, coefficient of thermal expansion of 12.44 × 10−6 / °C, and electrical conductivity of 2.13 × 105 (Ω cm) −1.

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.

scholarly journals Effect of iron doping on structural and optical properties of TiO2 thin film by sol–gel routed spin coating technique

2017 ◽  
Vol 07 (04) ◽  
pp. 1750024 ◽  
Author(s):  
Stephen Lourduraj ◽  
Rayar Victor Williams
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Sol Gel ◽  
Visible Region ◽  
Spin Coating Technique ◽  
Optical Measurements ◽  
Structural And Optical Properties ◽  
Coating Technique

Thin films of iron (Fe)-doped titanium dioxide (Fe:TiO[Formula: see text] were prepared by sol–gel spin coating technique and further calcined at 450[Formula: see text]C. The structural and optical properties of Fe-doped TiO2 thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV–vis) and atomic force microscopic (AFM) techniques. The XRD results confirm the nanostructured TiO2 thin films having crystalline nature with anatase phase. The characterization results show that the calcined thin films having high crystallinity and the effect of iron substitution lead to decreased crystallinity. The SEM investigations of Fe-doped TiO2 films also gave evidence that the films were continuous spherical shaped particles with a nanometric range of grain size and film was porous in nature. AFM analysis establishes that the uniformity of the TiO2 thin film with average roughness values. The optical measurements show that the films having high transparency in the visible region and the optical band gap energy of Fe-doped TiO2 film with iron (Fe) decrease with increase in iron content. These important requirements for the Fe:TiO2 films are to be used as window layers in solar cells.

EFFECT OF ANNEALING TEMPERATURE ON OPTICAL PROPERTIES OF TITANIUM DIOXIDE THIN FILMS PREPARED BY SOL-GEL METHOD

2011 ◽  
Vol 25 (31) ◽  
pp. 4163-4166 ◽  
Author(s):  
M. T. SARODE ◽  
P. N. SHELKE ◽  
Y. B. KHOLLAM ◽  
S. R. JADKAR ◽  
B. B. KALE ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Annealing Temperature ◽  
Anatase Phase ◽  
Sol Gel ◽  
Nanocrystalline Structure ◽  
Dip Coating ◽  
Optical Measurements ◽  
Crystallite Sizes

TiO 2 sol-gel thin films were deposited on glass substrates by dip coating method. Nanocrystalline TiO 2 thin films were prepared at 300°C. The effect of annealing temperature on optical properties of nanocrystalline TiO 2 thin films was studied. The films were characterized by different techniques: XRD, UV-visible spectroscopy, FTIR spectroscopy and FESEM. The characterization studies revealed that the films are crystallized as anatase phase and are nano-structured. The optical measurements were showed the indirect band gap between 3.31 and 3.35 eV with corresponding crystallite sizes between 8.9 and 3.7 nm at the temperatures 300, 400 and 500°C. The FESEM images of film were showed spherical nanocrystalline structure of TiO 2 particles with the crystallite sizes between 30 and 100 nm. It is also observed that refractive index of the film increases with increasing the annealing temperature. The smaller crystallite size gives larger band gap due to quantum size effects.

Optical properties of Mg0.05Zn0.95O/SiO2 nanocomposite films prepared by sol–gel technique

2005 ◽  
Vol 7 (2-3) ◽  
pp. 195-201 ◽  
Author(s):  
A. Dev ◽  
S. Chakrabarti ◽  
S. Kar ◽  
S. Chaudhuri
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Nanocomposite Films ◽  
Gel Technique

The role of mechanical, chemical and physical bonds in metal-ceramic bond strength

2018 ◽  
Vol 1 (92) ◽  
pp. 5-14 ◽  
Author(s):  
W. Czepułkowska ◽  
E. Wołowiec-Korecka ◽  
L. Klimek
Keyword(s):  
Thermal Expansion ◽  
Bond Strength ◽  
Coefficient Of Thermal Expansion ◽  
Bending Test ◽  
Dental Ceramic ◽  
Ceramic Bond ◽  
Metal Ceramic ◽  
Ceramic Crowns ◽  
The Impact

Purpose: A review regarding the mechanisms of metal-ceramic join is presented. Design/methodology/approach: The impact of the air-abrasion parameters on the mechanical bond strength of the ceramic crowns was discussed. The presence of opaque on the chemical bond was analysed. Research of the influence of the difference in the coefficient of thermal expansion values on the metal-ceramic bond was included. The methods of testing the bond strength were analysed. Findings: The metal substructure-dental ceramic bond strength is affected by all types of bond. In bond strength, 3-point bending test and shear test are mainly used. Created samples simulate the ceramic crowns veneered on one side. The role of physical bond on ceramic crowns veneered around metal substructure is unknown. Research limitations/implications: The prosthetic restorations with the ceramic surrounding whole the metal substructure are commonly used. The impact of shrinkage in the cylindrical deposition of the ceramic on metal substructure should be analysed. Practical implications: Numerical analysis and FEM simulation can be helpful in the analysis of the physical bond between the metal substructure and the dental ceramic around it. Originality/value: The impact of the type of the bond to metal-ceramic bond strength is presented, taking into account the cognitive gap in the influence of the coefficient of thermal expansion on the cylindrical placement of ceramic on the substructure.

Pore size and concentration effect of mesoporous silica nanoparticles on the coefficient of thermal expansion and optical transparency of poly(ether sulfone) films

2017 ◽  
Vol 19 (3) ◽  
pp. 1937-1944 ◽  
Author(s):  
Nhat Tri Vo ◽  
Astam K. Patra ◽  
Dukjoon Kim
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Optical Properties ◽  
Mesoporous Silica ◽  
Pore Size ◽  
Silica Nanoparticles ◽  
Coefficient Of Thermal Expansion ◽  
Mesoporous Silica Nanoparticles ◽  
Silica Nanoparticle ◽  
Mesoporous Silica Nanoparticle

A mesoporous silica nanoparticle filler that drastically enhances the dimensional thermal stability without sacrificing the optical properties of poly(ether sulfone) films was reported.

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