Thermoelectric properties of Ti-doped WO3 ceramics

Wang, Haiqing; Gan, Yingjie; Dong, Xiang; Peng, Shujie; Dong, Li Hua; Wang, Yu

doi:10.1007/s10854-012-0775-9

Cited by 18 publications

(8 citation statements)

References 26 publications

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“…The electrochromic materials are the class of materials having ability to modulate the reversible change in optical absorbance or reflectance when electrical voltage is applied to it. In addition to electrochromic, WO 3 thin films are known to have excellent photochromic [6], thermochromic [7], gasochromic [8], thermoelectric [9] and gas sensing [10,11] properties. Because of its electrochromic property, WO 3 has many direct applications in modern devices such as smart windows, large area information displays, rearview mirrors, etc.…”

Section: Introductionmentioning

confidence: 99%

Effect of precursors on the microstructural, optical, electrical and electrochromic properties of WO3 nanocrystalline thin films

Mukherjee

Sahay

2015

J Mater Sci: Mater Electron

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Spray-deposited tungsten oxide (WO 3 ) nanocrystalline thin films were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy in order to study the precursor induced changes in their structural and morphological properties. The crystallite size and the root mean square surface roughness have been found to be minimum for the WO 3 thin films prepared using ammonium tungstate. The optical and spectral studies of the films were carried out using UV-visible spectroscopy and photoluminescence spectroscopy. Electrical transport properties of the films were studied by measuring the film resistivity as a function of temperature. Electrochromic studies of the WO 3 films were carried out from cyclic voltammetry, chronocoulometry and chronoamperometry measurements. The films grown using ammonium tungstate exhibit high electrochromic reversibility (*91 %) and large charge storage capacity. The cyclic voltammograms of the films do not change even after 50 scan cycles, confirming the electrochromic stability in the WO 3 films. Overall, the film prepared using ammonium tungstate may be a suitable candidate for electrochromic devices.

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Section: Introductionmentioning

confidence: 99%

Effect of precursors on the microstructural, optical, electrical and electrochromic properties of WO3 nanocrystalline thin films

Mukherjee

Sahay

2015

J Mater Sci: Mater Electron

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“…It is recognized that electrical discharge machining can be used effectively in machining hard, high-strength, and temperature-resistant materials (Khan, Rahman, Kadirgama, Maleque, & Ishak, 2011c;Najiha, Rahman, Kamal, Yusoff, & Kadirgama, 2012;Yusoff, Mohamed Suffian, & Taib, 2011). EDM is also a process that demands expertise, and the mechanism of metal erosion during sparking is not fully understood due to the complex thermal conduction behaviors in the machining vicinity (Wang et al, 2012). Accordingly, it has been hard to establish models that accurately correlate the process variables and performance.…”

Section: Introductionmentioning

confidence: 99%

Electrode Wear Rate of Graphite Electrodes during Electrical Discharge Machining Processes on Titanium Alloy Ti-5Al-2.5Sn

Khan¹,

Rahman²,

Kadirgama³

2014

Int J Automot Mech Eng

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The proper selection of machining parameters can result in better machining performance in the electrical discharge machining process. However, this job is not always easy since the phenomena occurring between the electrodes in EDM are not yet fully understood. This study reports the development of a comprehensive mathematical model for the electrode wear rate (EWR) of a graphite tool in EDM on Ti-5Al-2.5Sn alloy, which has not yet been presented. Experiments for positive polarity of the graphite electrode, based on design of experiment (DOE), are first conducted. Modeling and analysis are carried out through the response surface methodology, utilizing the experimental results. A confirmation test is also executed to confirm the validity and the accuracy of the mathematical model developed. The confirmation test exhibits an average error of less than 6%. Negative electrode wear is evidenced for particular settings. The combination of 15A peak current, 350µs pulse-on time, 180µs pulse-off time and 95V servo-voltage and positive polarity causes negative tool wear. It is apparent that the developed model can evaluate electrode wear rate accurately and successfully.

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“…It was observed that a high nonlinear coefficient and low breakdown voltage could be obtained by addition of Ta 2 O 5 into the system . Furthermore, the addition of WO 3 would cause the formation of a solid solution with TiO 2 lattice due to ionic similarity, thus influencing the grain growth of TiO 2 (Su et al, 2003;Wang et al, 2012). On the other hand, cobalt (II,III) oxide (Co 3 O 4 ) was reported as one of the effective dopants that promotes densification of TiO 2 , as it creates oxygen vacancies, increases oxygen diffusion at grain boundaries, and promotes densification (Metz et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, cobalt (II,III) oxide (Co 3 O 4 ) was reported as one of the effective dopants that promotes densification of TiO 2 , as it creates oxygen vacancies, increases oxygen diffusion at grain boundaries, and promotes densification (Metz et al, 2007). Meanwhile, the addition of bismuth(III) oxide (Bi 2 O 3 ), should promote the growth of TiO 2 grains and the stability of the nonlinear current-voltage by providing the medium for liquid-phase sintering (Wang et al, 2012;Xu, Cheng, Yuan, Yang, & Lin, 2011 ). There is still a lack of research and study on the effect of the addition of Bi 2 O 3 to a TiO 2 powder based varistor.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Physical and Mechanical Properties of TiO2 Varistor Materials Prepared with Various Dopants

Daud¹,

Begum²,

Rahman³

et al. 2014

Int J Automot Mech Eng

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Varistors are the most efficient devices for the protection of power transmission lines and electronic devices against excessive transient surges. The current trends that require varistors with more functions have led to research to develop new ceramic varistor material and titanium dioxide (TiO 2 ) is the emerging new material. In this research nanosized TiO 2 was taken as the base materials to which a small amount of impurities was added as dopants for enhancing the properties. Ta 2 O 5 , WO 3, Bi 2 O 3 and Co 3 O 4 were used as dopants where the percentage of Bi 2 O 3 and Co 3 O 4 was fixed; 0.5% and 0.2% respectively. Samples were prepared with different weight percentages of dopants and sintered at a constant temperature of 1300˚C with 2 hour's holding time to observe the effect of these dopants on physical and mechanical properties of nanosized TiO 2 . Analysis was undertaken to evaluate the properties of the nanosized TiO 2 , such as green density, fired density, fired strength, axial and radial shrinkage. It was found that with the composition of 98.1% TiO 2 +0.7% Ta 2 O 5 +0.5% WO 3 +0.2%Co 3 O 4 +0.5%Bi 2 O 3 have a significant influence on the physical and mechanical properties, which is anticipated to improve the performance of varistor. With the improvement in the physical and mechanical properties of TiO 2 , the composite material has potential application in low voltage application devices.

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Thermoelectric properties of Ti-doped WO3 ceramics

Cited by 18 publications

References 26 publications

Effect of precursors on the microstructural, optical, electrical and electrochromic properties of WO3 nanocrystalline thin films

Effect of precursors on the microstructural, optical, electrical and electrochromic properties of WO3 nanocrystalline thin films

Electrode Wear Rate of Graphite Electrodes during Electrical Discharge Machining Processes on Titanium Alloy Ti-5Al-2.5Sn

Investigating the Physical and Mechanical Properties of TiO2 Varistor Materials Prepared with Various Dopants

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