Study on Characteristic and Compressive Property of Porous NiTi Alloys Fabricated by Thermal Explosion Method

2010 ◽  
Vol 160-162 ◽  
pp. 644-649 ◽  
Author(s):  
Qiang Li ◽  
Jing Yuan Yu ◽  
Xu Dong Sun
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Heating Rate ◽  
Thermal Explosion ◽  
Compressive Property ◽  
Porous Niti ◽  
Ni Powder ◽  
Explosion Method ◽  
Tini Phase ◽  
Niti Shape Memory Alloys

Porous NiTi shape memory alloys were fabricated by thermal explosion method using different Ti and Ni powder as initial materials. The effect of process parameters including heating rate, and particle size of Ti on pore characteristic and phase composition was analyzed. Microstructure, phase composition, and mechanical properties were studied by SEM, XRD, and compression test, respectively. The mechanism of thermal explosion reaction was studied. The results show higher heating rate and smaller Ti particle size result in higher porosity and bigger pores. The thermal explosion reaction starts with the melting of a eutectic between β-Ti(Ni) and Ti2Ni and the main phases of as-reacted products are TiNi phase which are the desired phases. NiTi2 and TiNi3 phases are also present in small amounts. The content of TiNi phase increases with increasing heating rate or decreasing Ti particle size. The compressive strength and Young’s modulus of compacts decrease with the increase of the porosity.

Study on Effect of Sintering Temperature on Microstructure and Compressive Property of Porous NiTi Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 480-483 ◽  
Author(s):  
Jing Yuan Yu ◽  
Qiang Li
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Compressive Property ◽  
Powder Metallurgy Method ◽  
Niti Alloys ◽  
Porous Niti ◽  
Universal Testing ◽  
Niti Phase

Porous NiTi alloys were prepared by powder metallurgy method using NH4HCO3as space-holder. The effect of sintering temperature on pore characteristic, phase composition and compressive property of porous NiTi alloys was studied by XRD, SEM, EDS and a universal testing machine. The results show with the increase of sintering temperature the porosity of porous NiTi alloys first increases and then decreases, but the content of NiTi phase, compressive strength and modulous of sintered products continuously increase. When sintered at 980°C for 2h, the porous NiTi alloys have higher porosity of 53.6%, better compressive strength of 173.7MPa and elastic modulous of 4.2GPa. The phases of sinter products are mainly composed by TiNi, Ti2Ni, and TiNi3phases.

Study on Preparation of Gradient Porous NiTi Alloys by Powder Metallurgy Method

2011 ◽  
Vol 299-300 ◽  
pp. 671-674
Author(s):  
Qiang Li ◽  
Jing Yuan Yu ◽  
Guo Chao Qi
Keyword(s):  
Phase Composition ◽  
Elastic Modulus ◽  
Powder Metallurgy ◽  
Porous Materials ◽  
Niti Alloy ◽  
Powder Metallurgy Method ◽  
Compressive Properties ◽  
Niti Alloys ◽  
Porous Niti ◽  
Tini Phase

Gradient porous NiTi alloys were fabricated by powder metallurgy method using NH4HCO3as space-holder. The effect of content and distribution of NH4HCO3on pore characteristic, phase composition and compressive properties was studied. The results showed the content of TiNi phase increased with the decrease of the content of NH4HCO3. When the distribution of NH4HCO3varying form 12wt%-12wt%-12wt% to 12wt%-6wt%-12wt% and 12wt%-0wt%-12wt%, the stress and elastic modulus of porous NiTi alloys increased from 228MPa to 321MP and 446MPa, from 4.8GPa to 5.6GPa and 6.8GPa, respectively. Compared with uniform porous materials, gradient porous NiTi alloy exhibited better superelasticity.

Modeling and Analysis of Compressive Properties of Porous NiTi Shape Memory Alloy Using Artificial Neural Network

2008 ◽  
Vol 41-42 ◽  
pp. 135-140 ◽  
Author(s):  
Qiang Li ◽  
Xu Dong Sun ◽  
Jing Yuan Yu ◽  
Zhi Gang Liu ◽  
Kai Duan
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermal Explosion ◽  
Process Parameters ◽  
Niti Shape Memory Alloy ◽  
Compressive Properties ◽  
Porous Niti ◽  
Bp Model

Artificial neural network (ANN) is an intriguing data processing technique. Over the last decade, it was applied widely in the chemistry field, but there were few applications in the porous NiTi shape memory alloy (SMA). In this paper, 32 sets of samples from thermal explosion experiments were used to build a three-layer BP (back propagation) neural network model. According to the registered BP model, the effect of process parameters including heating rate ( ), green density ( ) and particle size of Ti ( d ) on compressive properties of reacted products including ultimate compressive strength ( v D σ ) and ultimate compressive strain (ε ) was analyzed. The predicted results agree with the actual data within reasonable experimental error, which shows that the BP model is a practically very useful tool in the properties analysis and process parameters design of the porous NiTi SMA prepared by thermal explosion method.

Microbial-Induced Mineralization of Zinc Ions Based on the Degradation of Toluene and Its Characterization

2021 ◽  
Vol 13 (4) ◽  
pp. 656-661
Author(s):  
Yiyan Lv ◽  
Qiwei Zhan ◽  
Xiaoniu Yu
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Surface Morphology ◽  
Organic Compounds ◽  
Low Cost ◽  
Zinc Ion ◽  
Zinc Ions ◽  
Quick Response ◽  
Zinc Carbonate ◽  
Carbonate Ions

Microbial-induced degradation of aromatic organic compounds and mineralization of zinc ions have attracted much attention because of its low cost, simple operation and quick response. This research, toluene was decomposed and made the concentration of carbonate ions increased accordingly by the enzymatic pressing of microorganisms, meanwhile carbonate ions mineralized zinc ions into carbonate precipitations. The composition and microstructure were analyzed systematically. The analysis results indicated that carbonate precipitations, basic zinc carbonate, could be successfully prepared by microbial method. The particle size of basic zinc carbonate was nanometer, and its shape was near-spherical. Furthermore, the phase composition, functional groups and surface morphology of the precipitations prepared by different methods were basically the same. This work provided a new method for remediation of zinc ion pollution based on the degradation of toluene.

INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.
Keyword(s):  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Heating Rate ◽  
Degradation Process ◽  
Heating Rates ◽  
Initial Stage ◽  
Poultry Processing ◽  
Effect Of Particle Size ◽  
Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process. 

scholarly journals Study of the properties of Ce3+-doped fluoride nanophosphors: phase composition, morphology, luminescence

2021 ◽  
Vol 2056 (1) ◽  
pp. 012048
Author(s):  
A M Dorokhina ◽  
V V Bakhmetyev ◽  
H Kominami ◽  
A Toru ◽  
M Hisashi
Keyword(s):  
Particle Size ◽  
Photodynamic Therapy ◽  
Phase Composition ◽  
Polyethylene Glycol ◽  
Ethylene Glycol ◽  
Solvothermal Synthesis ◽  
Luminescent Properties ◽  
Optimal Duration ◽  
Oncological Diseases ◽  
Synthesis Medium

Abstract To date, nanophosphors have found application in various fields, one of which is medicine. These phosphors were developed with the aim to become one of the components of a drug for photodynamic therapy of oncological diseases. The aim of this work was to study the effect of the duration, environment, and stabilizers of solvothermal synthesis on the microstructure and luminescent properties of the YF3:Ce nanophosphor. The solvothermal synthesis technique was carried out in three different media: water, ethanol, and ethylene glycol. The optimal duration of the synthesis was also determined (the synthesis was carried out at a temperature of 200°C for 4…20 hours). The dependence of the YF3 luminescence on the phase composition and the solvothermal synthesis medium was studied. Using SEM, the morphology and particle size of YF3:Ce phosphors were studied depending on different stabilizers (polyethylene glycol, polyethyleneimine, polyvinylpyrrolidone). The luminescence intensity of YF3:Ce and Na(Y1,5Na0,5)F6:Ce samples was compared.

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