The relationship between temperature, mechanical properties, and the coefficient of thermal expansion of steatite and forsterite ceramics

1965 ◽  
Vol 22 (12) ◽  
pp. 794-797
Author(s):  
G. I. Berdov
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
The Relationship

Thermal Expansion and Laser Trim Stability of Ruthenium Based Thick Film Resistors on Alumina and on Multilayer Dielectric

1982 ◽  
Vol 1 (1) ◽  
pp. 24-27 ◽  
Author(s):  
I. Taitl
Keyword(s):  
Thermal Expansion ◽  
Thick Film ◽  
Chemical Structure ◽  
Coefficient Of Thermal Expansion ◽  
Ruthenium Dioxide ◽  
Theoretical Conclusion ◽  
Film Resistor ◽  
Thick Film Resistor ◽  
The Relationship ◽  
Multilayer Dielectric

Fired resistors exhibit variations which are minimised by abrasive and laser trimming. The latter may cause unstable behaviour which is further aggravated by thermal shock. The chemical structure of a thick film resistor is analysed with respect to mechanical stress, and the theoretical conclusion that the coefficient of thermal expansion of the resistor should be equal to or smaller than that of the substrate is verified experimentally. The thermal behaviour of ruthenium dioxide is examined and a range of CTE values are determined for materials of varying chemical composition. The relationship between CTE and post laser trimming stability is demonstrated on four thick film resistors which differ in thermal expansion. It is pointed out that formulations with high metallic content can absorb tensile stress by elastic deformation, thus minimising the formation or propagation of laser induced cracks.

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

Bi-Material Re-Entrant Triangle Cellular Structures Incorporating Tailorable Thermal Expansion and Tunable Poisson's Ratio1

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Xiaobing He ◽  
Jingjun Yu ◽  
Yan Xie
Keyword(s):  
Thermal Expansion ◽  
Cellular Structure ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Planar Lattice ◽  
Lattice Cell ◽  
Thermoelasticity Equation ◽  
Triangle Lattice ◽  
Temperature Load ◽  
The Relationship

Abstract Based on the bi-material triangle lattice cell, a new cellular structure, bi-material re-entrant triangle (BRT) cellular structure, is devised to incorporate tailorable coefficient of thermal expansion (CTE) and tunable Poisson's ratio (PR) properties by replacing the straight base of a triangle with two hypotenuse members. A general thermoelasticity equation to systematically build the relationship among the external force, the temperature load, and the deformation for planar lattice structures with bounded joints is derived and then embedded into a theoretical model for the devised BRT structure. Using assembled thermoelasticity equation, effective PR, Young's modulus, as well as CTE are computed. In order to guide designers to construct initial concepts, the design domain for coupling negative CTE and negative PR properties is plotted. The material-property-combination region that can be achieved by this cellular structure is determined within an Ashby material selection chart of CTE versus PR. Nine available combinations of CTE and PR properties are extracted and demonstrated with abaqus simulation.

Determination of Mechanical Properties of Thin Film on Silicon Wafer

2003 ◽  
Author(s):  
Enboa Wu ◽  
Albert J. D. Yang ◽  
Ching-An Shao ◽  
C. S. Yen
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Silicon Wafer ◽  
Coefficient Of Thermal Expansion ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Bulk State

Nondestructive determination of Young’s modulus, coefficient of thermal expansion, Poisson ratio, and thickness of a thin film has long been a difficult but important issue as the film of micrometer order thick might behave differently from that in the bulk state. In this paper, we have successfully demonstrated the capability of determining all these four parameters at one time. This novel method includes use of the digital phase-shifting reflection moire´ (DPRM) technique to record the slope of wafer warpage under temperature drop condition. In the experiment, 1-um thick aluminum was sputtered on a 6-in silicon wafer. The convolution relationship between the measured data and the mechanical properties was constructed numerically using the conventional 3D finite element code. The genetic algorithm (GA) was adopted as the searching tool for search of the optimal mechanical properties of the film. It was found that the determined data for Young’s modulus (E), Coefficient of Thermal Expansion (CTE), Poisson ratio (ν), and thickness (h) of the 1.00 um thick aluminum film were 104.2Gpa, 38.0 ppm/°C, 0.38, and 0.98 um, respectively, whereas that in the bulk state were measured to be E=71.4 Gpa, CTE=23.0 ppm/°C, and ν=0.34. The significantly larger values on the Young’s modulus and the coefficient of thermal expansion determined by this method might be attributed to the smaller dislocation density due to the thin dimension and formation of the 5-nm layer of Al2O3 formed on top of the 1-um thick sputtered film. The Young’s Modulus and the Poisson ratio of this nano-scale Al2O3 film were then determined. Their values are consistent with the physical intuition of the microstructure.

scholarly journals The Use of Recycled Carpet in Low-Cost Composite Tooling Materials

Recycling ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 12 ◽  
Author(s):  
Kunal Mishra ◽  
Sarat Das ◽  
Ranji Vaidyanathan
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Low Cost ◽  
Value Engineering ◽  
Compressive Properties ◽  
Structural Composites ◽  
Environmental Deterioration ◽  
Composite Tooling

More than 250,000 metric tons (600 million pounds) of carpet are dumped in landfills every year. That creates a significant concern regarding environmental deterioration and economic liability. It is therefore imperative to develop sustainable post-consumer carpet-based products for high-value engineering applications such as composite tooling. To be considered as an acceptable composite tooling material, the composite needs to meet certain required properties such as a low coefficient of thermal expansion, excellent compressive properties, and high a hardness value after repeated exposure to curing cycles. The tooling composites must also exhibit the ability to endure several curing cycles, without deteriorating the mechanical properties. In the present investigation, post-consumer carpet has been recycled in the form of structural composites for tooling applications. The recycled carpet composites have been reinforced with 0.5 wt.% of graphene nanoplatelets to modify the material properties of the carpet composites. The results from compressive and hardness experiments demonstrate that the recycled carpet preserved its mechanical integrity even after several curing cycles. This indicates that recycled carpet composites have the potential to be a low-cost composite tooling alternative for the industry.

Rheological and Thermomechanical Properties of Meso and Non-Porous Silica Filled Epoxy Composites

2015 ◽  
Vol 815 ◽  
pp. 67-71
Author(s):  
Gang Li ◽  
Peng Li Zhu ◽  
Tao Zhao ◽  
Rong Sun ◽  
Daniel Lu
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Glass Transition ◽  
Mesoporous Silica ◽  
Coefficient Of Thermal Expansion ◽  
Porous Silica ◽  
Thermomechanical Properties ◽  
Epoxy Composites ◽  
Silica Microspheres ◽  
Silica Filler

In the present study, epoxy based composite filled with meso and non-porous silica microspheres with similar size were prepared respectively and their rheological and thermo-mechanical properties were studied systematically. The results showed that the mesoporous silica/epoxy composites showed much higher viscosity, storage modulus and glass transition temperature (Tg) while lower coefficient of thermal expansion (CTE) than did epoxy composites with nonporous silica particles, which could be attributed to the stronger interface interaction between the mesoporous silica filler with larger specific surface area (BET) and the epoxy matrix.

Influences of High Temperature Treatment of C/C on the Mechanical Properties of C/C-SiC Composites

2015 ◽  
Vol 816 ◽  
pp. 78-83
Author(s):  
Dong Lin ◽  
Jing Wang ◽  
Chang Rui Zhang ◽  
Ying Bin Cao ◽  
Rong Jun Liu
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
High Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Sic Composites

C/C-SiC composite as low expansion material for space opto-mechanical structures was prepared by gaseous silicon infiltration after high temperature treatment (HTT) on C/C. 2000°C and 2400°C were selected as the treatment temperatures for C/C to study the influences on the properties of C/C-SiC composite. The graphitization level of amorphous C in C/C was improved by HTT. The porosity of C/C increased from 32.88% to 34.25% (2000°C) and 41.06% (2400°C) respectively. In addition, a higher HTT temperature led to a higher density of C/C-SiC composite and a lower SiC content. Furthermore, the mechanical properties and coefficient of thermal expansion (CTE) of the composite decreased as the temperature increased. After 2000°C HTT, the CTE of C/C-SiC composite decreased to-0.055×10-6·K-1 and the mechanical properties (218 MPa) could meet the application demand at the same time.

scholarly journals Technological Relevance, Research Prospect and Applications of Aluminium-Silicon Carbide-Graphite Hybrid Metal Matrix Composites for Thermal Characterization

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
S A Mohan Krishna ◽  
T N Shridhar ◽  
L Krishnamurthy ◽  
K B Vinay ◽  
G V Naveen Prakash
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Thermal Expansion ◽  
Hybrid Composites ◽  
Coefficient Of Thermal Expansion ◽  
Aluminium Matrix ◽  
Matrix Composites ◽  
Aluminium Matrix Composites ◽  
Research Prospect

Aluminium matrix composites belong to the family of materials whose mechanical, tribological, thermal and electrical properties can be customized effectively. Most of the commercial work on MMCs has been highlighted on Aluminium as the matrix material. The combination of light weight, environmental resistance and beneficial mechanical properties has made Aluminium alloys exceedingly popular; these properties also make Aluminium best suited for use as a matrix metal. The thermophysical properties of these composites can be tailor made and have excellent specific mechanical properties. These composites can be fabricated with ease. Aluminium matrix composites reinforced with the particles of Silicon Carbide possess high yield strength, low coefficient of thermal expansion or thermal expansivity, high modulus of elasticity and excellent wear resistance by maintaining volume proportion up to 20%. Aluminium hybrid composites can be customized to provide moderate Coefficient of Thermal Expansion (CTE) and high thermal conductivity that are favorable for the applications pertaining to thermal management equipment. However, it is necessary to evaluate different percentage combinations of reinforcements with matrix Aluminium to check for thermal stability and to measure thermal conductivity and coefficient of thermal expansion. It is expected that, Aluminium-Silicon Carbide-Graphite hybrid composites can be used as load bearing material for the above applications. In this paper, a review about the said hybrid composites to investigate thermal properties for engineering applications have been discussed based on its technological relevance, applications and research prospect.

Investigation on Silicon-Glass Electrostatic Bonding Time Experiment

2011 ◽  
Vol 483 ◽  
pp. 78-82
Author(s):  
Xiao Wei Liu ◽  
Jia Lu Tang ◽  
Rong Yan Chuai ◽  
Hai Feng Zhang ◽  
Xi Lian Wang
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Bonding Process ◽  
Bonding Time ◽  
Relationship Of ◽  
The Mathematical Model ◽  
The Relationship ◽  
Electrostatic Bonding

In this paper, we make a detail analysis of some factors, which affects the electrostatic bonding process. According to the electrical properties of glass, combined with the principle of electrostatic bonding, we analysed the relationship of critical bonding time, voltage and temperature as well as the factors which affect electrostatic bonding. Then we come up with the mathematical model of the intensity and temperature of electrostatic bonding. In accordance with the above-mentioned formula and the experimental data, we can get the following conclusions: the intensity of electrostatic bonding is much greater between 280°C to 370°C; the best temperature for this bonding is about 350°C; however, when the temperature is below 280°C,the intensity of electrostatic bonding is lower due to the great impact of particles under low temperature; but when the temperature is higher than 370°C,the mismatch of coefficient of thermal expansion of silicon and glass gets larger, then as a result, the intensity of this bonding has a significant decrease with the increasing of temperature.

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