Effects of the deep traps on the thermal-stability property of CaAl2 O4 : Eu2+ phosphor

2018 ◽  
Vol 101 (8) ◽  
pp. 3480-3488 ◽  
Author(s):  
Zhichao Liu ◽  
Lei Zhao ◽  
Wenbo Chen ◽  
Shuangyu Xin ◽  
Xiaotong Fan ◽  
...  
2010 ◽  
Vol 150-151 ◽  
pp. 951-955
Author(s):  
Dan Dan Yang ◽  
Hai Ping Xu ◽  
Lu Ping Zhu ◽  
Yi Hua Wu

Nanocomposites of polyacrylonitrile (PAN) and Organophilic alpha-zirconium phosphate (OZrP) were prepared by gelation/crystallization. OZrP was prepared using cetyl trimethyl ammonium bromide (CTAB). The structure of PAN/OZrP nanocomposites was characterized by X-ray diffractometry (XRD) and high resolution transmission electron microscopy (HRTEM). The results showed that an intercalated or exfoliated structure was formed. Thermogravimetric analysis (TGA) was applied to characterize thermal stability property, which indicated that the thermal stability of PAN/OZrP nanocomposites was improved compared with that of pure PAN. HRTEM and Laser Raman spectroscopy were used to analyze the microstructure of the chars of PAN/OZrP nanocomposites.


2016 ◽  
Vol 36 (8) ◽  
pp. 805-811 ◽  
Author(s):  
Rui Li ◽  
Cheng Zhou ◽  
Lin Yu ◽  
Yang Chen ◽  
Huawei Zou ◽  
...  

Abstract The thermal stability and ablation properties of silicone rubber composites filled with Fe2O3, SnO2, CuO, MgO, and Al2O3 were researched using thermogravimetric analysis (TGA) and the oxyacetylene torch test. The effecting laws of metallic oxide on the thermal stability and ablation properties of silicone rubber composites were analyzed by uniform design method. TGA indicated that the thermal degradation process of silicone rubber composites took a two mass loss steps. The effecting order of metallic oxide on enhancing thermal stability property of silicone rubber composites in step 1 was MgO>SnO2> Fe2O3>Al2O3>CuO, whereas the order in step 2 was CuO> SnO2>MgO>Fe2O3>Al2O3. Furthermore, Fe2O3 and SnO2 had an evident synergistic effect on enhancing the thermal stability property and residual carbon of silicone rubber composites. The oxyacetylene torch test showed that the effecting order of metallic oxide on increasing ablation resistance property of silicone rubber composites in ablation process was CuO>MgO>Fe2O3>SnO2>Al2O3. Moreover, the line ablation rate of specimen 2 was 0.0499, which indicated that it had the best ablation resistance among all uniform samples. Furthermore, scanning electron microscopy also showed that the porous ceramic layer became much denser after the ablation process, and this will significantly improve the ablation resistance property.


2021 ◽  
Vol 317 ◽  
pp. 300-304
Author(s):  
Mazlina Mustafa Kamal

In recent years, automotive hose and belt specifications have changed, requiring longer product life in terms of swelling, wear and heat ageing. Diene-based rubbers, such as natural rubber (NR) and styrene-butadiene rubber (SBR), have been widely used in diverse industries. However, some apparent defects such as limited ageing resistance and large compression set, have been demonstrated in some rubbers cured by sulfur or peroxides. In the making of general and industrial rubber goods, short production and sufficient scorch time is crucial especially by using an injection moulding. In this work, blend of Epoxidised Natural Rubber (ENR 25) and Butadiene was developed with two types of curing systems namely Conventional and Efficient Vulcanisation system. The aim of the study is to produce a satisfactory heat resistance rubber compounds and adequate process safety for rubber manufacturing. Results showed that curing system applied significantly affected thermal stability property of the compounds. Modulus and hardness of the blends appeared to decrease progressively with ageing. However, greater thermal stability especially ageing at 100°C for 200h was observed with compound containing efficient curing system compared to conventional curing system which corresponded to the cross link density attributed by the torque value and dynamic mechanical analysis. The results on stiffness however was effected by the curing system applied. The influence of cure temperature on the chemical crosslink density on both cure systems are being investigated. The network results will be correlated with the technical properties.


Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization


Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.


Author(s):  
J. Liu ◽  
N. D. Theodore ◽  
D. Adams ◽  
S. Russell ◽  
T. L. Alford ◽  
...  

Copper-based metallization has recently attracted extensive research because of its potential application in ultra-large-scale integration (ULSI) of semiconductor devices. The feasibility of copper metallization is, however, limited due to its thermal stability issues. In order to utilize copper in metallization systems diffusion barriers such as titanium nitride and other refractory materials, have been employed to enhance the thermal stability of copper. Titanium nitride layers can be formed by annealing Cu(Ti) alloy film evaporated on thermally grown SiO2 substrates in an ammonia ambient. We report here the microstructural evolution of Cu(Ti)/SiO2 layers during annealing in NH3 flowing ambient.The Cu(Ti) films used in this experiment were prepared by electron beam evaporation onto thermally grown SiO2 substrates. The nominal composition of the Cu(Ti) alloy was Cu73Ti27. Thermal treatments were conducted in NH3 flowing ambient for 30 minutes at temperatures ranging from 450°C to 650°C. Cross-section TEM specimens were prepared by the standard procedure.


2020 ◽  
Author(s):  
Feng Xiao ◽  
Bin Yao ◽  
Pavankumar Challa Sasi ◽  
Svetlana Golovko ◽  
Dana Soli ◽  
...  

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