scholarly journals Genesis of Structure and Properties of the Zeolite-Like Cement Matrices of the System Na(K)-Al2O3-SiO2-H2O within a Temperature Range of 20–1200°C

2021 ◽  
Author(s):  
Pavel Krivenko ◽  
Volodymyr Kyrychok
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Performance ◽  
Cement Matrix ◽  
Structure And Properties ◽  
Curing Conditions ◽  
Temperature Range ◽  
Intumescent Coatings ◽  
Alkaline Component ◽  
Cement Matrices

The chapter deals with a genesis of structure and properties of the zeolite-like cement matrices of the Na(K)-Al2O3-SiO2-H2O system within a temperature range of 20–1200°С. Due to the fact that zeolite-like structures and their characteristics vary within wide ranges, materials with high-performance properties can be obtained through regulation of the structure formation processes. This can be provided by a proper choice of type of an aluminosilicate component, cation of an alkaline component and additives, including Ca-containing ones, and curing conditions. When the cement matrix formation process is appropriately directed, the zeolite-like products (hydrosodalite, analcime, chabasite, faujasite etc.) dominate in the microstructure that is formed. The ability of some zeolites to recrystallize with temperature increase into stable feldspar-like aluminosilicates without destroying the basic skeleton opens a pathway that is worth to explore in the production of materials similar to low temperature ceramics, intumescent coatings, high temperature and corrosion resistant structures, etc. The examples are given on how to use the above cement matrices for making some of the above listed materials.

Basic Experiment on Lithium Removal Technique

2012 ◽  
Author(s):  
Tomohiro Furukawa ◽  
Yasushi Hirakawa
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Dissolution Rate ◽  
Chemical Reaction ◽  
Pure Water ◽  
Preliminary Investigation ◽  
Testing Temperature ◽  
Temperature Range ◽  
Removal Technique ◽  
Good Agreement

As a preliminary investigation into the establishment of a lithium removal technique for the components used at the International Fusion Materials Irradiation Facility (IFMIF), experiments were performed on the dissolution of lithium in three solvents: ethanol, pure water, and ethanol–water. In these experiments, hemispherical lithium was immersed in the solvents at constant temperatures, and the degree of dissolution was measured continuously from the height of the sample. From the obtained data, the average dissolution rate in the solvents at each testing temperature (10–90 °C) and the amount of hydrogen generated by the chemical reaction were calculated. The average dissolution rates in ethanol, pure water, and ethanol–water at 30 °C were 0.01, 1.6, and 0.43 mm/min, respectively. Although the average dissolution rate increased with the testing temperature in the low-temperature range (10–50 °C) for all solvents, this increase was saturated in the high-temperature range (50–90 °C) in experiments with pure water and ethanol–water as solvents. The volume of gas collected during each experiment was in good agreement with the volume of hydrogen assumed to be generated from the chemical reaction of lithium with the solvents.

scholarly journals A Study of Isothermal Curing of PMI Using DMA

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Jing Zhang ◽  
Rui Ye ◽  
Jun Zou ◽  
Jijun Tang ◽  
Hongliang Wang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Nonequilibrium Thermodynamic ◽  
Fluctuation Theory ◽  
Avrami Equation ◽  
High Temperature Range ◽  
Dynamic Mechanical ◽  
Temperature Range ◽  
Thermodynamic Fluctuation ◽  
Relative Conversion

The isothermal curing of polymethacrylimide (PMI) is studied through the use of dynamic mechanical analysis (DMA). Based on the growth rate of measured dynamic mechanical property, the relative conversion is defined to investigate the evolution of storage modulusE′at different curing temperatures. Hsich’s nonequilibrium thermodynamic fluctuation theory, Avrami equation, and isoconversional methods are used to analyze isothermal cure kinetics of PMI. The results show that there are different increase modes ofE′at low temperature range and high temperature range, respectively. In low temperature range, the relative conversion curves include a transitional stage which is found to be strongly frequency-dependent, but this stage is not observed in the relative conversion curve in high temperature range. During the isothermal curing process, the relative evolution ofE′can be described by Hsich’s nonequilibrium thermodynamic fluctuation theory and Avrami equation. Moreover, the values and evolutions of activation energy are different in two temperature ranges, which suggest that the curing mechanism probably has changed.

Study on the Thermodynamics and Kinetics in the Combustion Reaction between Titanium and Boron Powders

2007 ◽  
Vol 351 ◽  
pp. 189-194 ◽  
Author(s):  
K. Wang ◽  
Zheng Yi Fu ◽  
Wei Min Wang ◽  
Yu Cheng Wang ◽  
H. Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Low Temperature ◽  
Experimental Analysis ◽  
Combustion Temperature ◽  
Raw Materials ◽  
Temperature Range ◽  
Thermodynamics And Kinetics ◽  
Diffusion Controlled ◽  
Calculated Activation

Combustion synthesis of titanium diboride(TiB2) from titanium(Ti) and boron(B) powders was studied by theoretical calculation and experimental analysis. In high temperature range or in low temperature range, the calculated activation energies are 140KJ/mol or 355KJ/mol respectively, which is described by a change from dissolution-precipitation controlled process to diffusion-controlled process. With the increase of particle size of the raw materials, combustion temperature and propagating rate will both reduce. The propagating rate decreases with the addition of diluents. Further increase of diluents may result in a stop of the combustion wave halfway or even a failure of ignition.

Linear red/green ratiometric thermometry of Ho3+/Cr3+ co-doped red up-conversion tungstate materials

2021 ◽  
Author(s):  
Yan Zhao ◽  
Xusheng Wang ◽  
Rui Hu ◽  
Yanxia Li
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Sensitivity ◽  
Temperature Sensing ◽  
High Temperature Range ◽  
Temperature Range ◽  
Co Doped ◽  
Sensing Performance

Existing optical thermometers are faced with the challenges of high sensitivity limited to a very narrow high temperature range, while also lacking low temperature sensing performance. A new linear up-conversion...

HIGH-TEMPERATURE THERMOPLASTIC ELASTOMERS FROM RUBBER–PLASTIC BLENDS: A STATE-OF-THE-ART REVIEW

2017 ◽  
Vol 90 (1) ◽  
pp. 1-36 ◽  
Author(s):  
Shib Shankar Banerjee ◽  
Anil K. Bhowmick
Keyword(s):  
High Temperature ◽  
Automotive Industry ◽  
High Performance ◽  
State Of The Art ◽  
Thermoplastic Elastomers ◽  
Structure And Properties ◽  
Temperature Performance ◽  
Thermoplastic Vulcanizates ◽  
Different Types

ABSTRACT This article reviews different types of high-temperature thermoplastic elastomers and thermoplastic vulcanizates from rubber-plastic blends. Preparation, structure, and properties of these materials are discussed briefly. Strategies to further improve the high-temperature performance of these materials are presented herein. A synopsis of the applications of these high-performance materials in the automotive industry is reported, pointing out the gaps to motivate potential research in this field.

scholarly journals Study on Performance Optimization of Composite Natural Asphalt Modified Gussasphalt Mix

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Huadong Sun ◽  
Peng Jiang ◽  
Yongling Ding ◽  
Laixue Pang ◽  
Yinbin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Performance Optimization ◽  
Temperature Stability ◽  
Superior Performance ◽  
Engineering Properties ◽  
High Temperature Stability ◽  
Temperature Range ◽  
Natural Asphalt ◽  
Modified Binder

In order to systematically study and develop a type of gussasphalt (GA) mix with superior performance, namely GA-10; the effect of Qingchuan Rock Asphalt (QRA) and Trinidad Lake asphalt (TLA) on the GA-10 mix was assessed based on the study of composite natural asphalt modified gussasphalt (CNAMGA) binder. Various analytical tests were used to evaluate the engineering properties, thermal stability and microstructure of CNAMGA mix. The results indicate that the stability of QRA modified binder and TLA modified binder in the normal temperature range and the high temperature range have been improved, and the temperature susceptibility is reduced. The optimal asphalt–aggregate ratio of the GA mix is determined to be 9.7%, which has good high-temperature stability, low-temperature crack resistance and construction workability. The QRA mix has better high-temperature stability than the TLA mix, whereas the low-temperature cracking resistance of the TLA mix is better than that of the QRA mix. The two kinds of GA-10 mix have similar construction workability. The fact that the abundant fine aggregates wrapped in binder fill the coarse aggregates surface contributes to the better adhesion of the GA asphalt concrete. The distribution of aggregate and binder is relatively uniform with fewer pores, and the overall proportion of the binder is greater than that of aggregate.

Low Temperature, Fast Sintering of Micro-Scale Silver Paste for Die Attach for 300°C Applications

2015 ◽  
Vol 2015 (1) ◽  
pp. 000654-000660 ◽  
Author(s):  
Fang Yu ◽  
R. Wayne Johnson ◽  
Michael C. Hamilton
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Performance ◽  
High Reliability ◽  
Sintering Process ◽  
Power Devices ◽  
C Storage ◽  
Die Attach ◽  
Increasing Demand ◽  
High Lead

With an increasing demand for SiC and GaN high power devices that operate at high temperature, traditional solder materials are reaching their limitations in performance. In addition, there is a strong desire to eliminate high lead containing solders in Si power device packaging for use over conventional temperature range. Low temperature Ag sintering technology is a promising method for high performance lead-free die attachment. In a previous study, a pressureless sintering process and suitable metallization were demonstrated to provide high reliability die attach by using micro-size Ag sintering. The resulting die attach layer had approximately 30% porosity. In this work, a low temperature pressure-assisted fast sintering process was examined. The porosity was decreased from 30% to 15% with application of a low pressure (7.6MPa) during a one minute sintering process. The shear strength for a 3 mm × 3 mm die was 70 MPa and the 8 mm × 8 mm die could not be sheared off due to a 100 kg shear module force limit. Both the Ag and Au metallization (die and substrate) were studied. Furthermore, a new substrate metallization combination was found that allows the use of Au thick film metallized substrates. High temperature (300 °C) storage tests for up to 2000 hours aging were conducted and results are presented.

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