KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/kmitl/1

Browse

Search Results

Now showing 1 - 6 of 6

Some of the metrics are blocked by your
consent settings
Enhancement of thermoelectric performance and mechanical reliability in electrodeposited chitosan nanofiber-bismuth telluride nanocomposite
(2026-07-01)
Tian, Jianghan
;
Gobpant, Jakrit
;
Van Toan, Nguyen
;
Theekhasuk, Nattharika
;
Pham, Cong Kha
Thermoelectric generators (TEGs) offer a promising route for converting waste heat into electrical energy; however, the practical implementation of high-performance micro-TEGs (μTEGs) is limited by the material performance and mechanical fragility of thick bismuth telluride (Bi<inf>2</inf>Te<inf>3</inf>) films. Although thick thermoelectric layers are required to sustain sufficient temperature gradients, conventional fabrication often induces residual stress, leading to cracking and structural failure. In this work, we introduce a sustainable synthesis strategy by incorporating bio-derived chitosan nanofibers (ChNFs) into the electrodeposition process. The amino and hydroxyl functional groups of ChNFs promote interfacial bonding and nucleation, enabling the rapid growth of dense, crack-free composite films with thicknesses up to 1000 μm. The introduction of ChNFs also creates abundant phonon-scattering interfaces, significantly reducing lattice thermal conductivity from 1.48 to 0.29 W m−1 K−1 and resulting in a 303% increase in the room-temperature figure of merit (ZT), from 0.12 to 0.50. At an optimal loading of 0.0123 wt%, the composite films exhibit a 15% increase in hardness while maintaining structural integrity. These results demonstrate a multifunctional materials design strategy that simultaneously enhances thermoelectric performance, mechanical robustness, and fabrication scalability. The ChNF–Bi<inf>2</inf>Te<inf>3</inf> nanocomposites provide a viable green pathway for developing reliable thick films for next-generation self-powered electronics and compact waste-heat harvesting systems.
1
Some of the metrics are blocked by your
consent settings
The investigation of corrosion behavior of electrodeposited Co-Fe alloys surface with phase and 3D reconstruction of image using TIE and TPE
(2018-01-01)
Srisuwan, Thanthanat
;
Somphonsane, Ratchanok
;
Sutthiruangwong, Sutha
;
Buranasiri, Prathan
In this research, phase retrieval using transport of intensity equation (TIE) and transport of phase equation (TPE) have been used for determine the surface of corrosion behavior of electrodeposited Co-Fe alloys, an important component in hard disk drive. Without interferometer as used in digital holography technique, by using TIE and TPE, our observing setup is simple and compact. The experimental results show the capability of TIE and TPE for observing the pitting corrosion. The pitting corrosion of Co-Fe image results have also shown. The dynamic process of microstructure surface system would be conducted and may be applied to hard disk drive industry in the future.
2
Some of the metrics are blocked by your
consent settings
Corrosion behavior of electrodeposited Co-Fe alloys in aerated solutions
(2017-05-01)
Chansena, A.
;
Sutthiruangwong, S.
Co-Fe alloy is an important component for reader-writer in hard disk drive. The surface of the alloy is exposed to the environment both in gas phase and in liquid phase during manufacturing process. The study of corrosion behavior of Co-Fe alloys can provide useful fundamental data for reader-writer production planning especially when corrosion becomes a major problem. The corrosion study of electrodeposited Co-Fe alloys from cyclic galvanodynamic polarization was performed using potentiodynamic polarization technique. The composition of electrodeposited Co-Fe alloys was determined by X-ray fluorescence spectrometry. The patterns from X-ray diffractometer showed that the crystal structure of electrodeposited Co-Fe alloys was body-centered cubic. A vibrating sample magnetometer was used for magnetic measurements. The saturation magnetization (M<inf>s</inf>) was increased and the intrinsic coercivity (H<inf>ci</inf>) was decreased with increasing Fe content. The corrosion rate study was performed in aerated deionized water and aerated acidic solutions at pH 3, 4 and 5. The corrosion rate diagram for Co-Fe alloys was constructed. It was found that the corrosion rate of Co-Fe alloys was increased with increasing Fe content in both aerated deionized water and aerated acidic solutions. In aerated pH 3 solution, the Co-Fe alloy containing 78.8% Fe showed the highest corrosion rate of 7.7 mm yr−1 with the highest M<inf>s</inf> of 32.0 A m2 kg−1. The corrosion rate of the alloy with 23.8% Fe was at 1.1 mm yr−1 with M<inf>s</inf> of 1.2 A m2 kg−1. In aerated deionized water, the alloy with the highest Fe content of 78.5% still showed the highest corrosion rate of 0.0059 mm yr−1 while the alloy with the lowest Fe content of 20.4% gave the lowest corrosion rate of 0.0045 mm yr−1.
Some of the metrics are blocked by your
consent settings
Optimized manganese oxide nanosheet/manganese oxide thin film/ multiwalled carbon nanotubes as hybrid electrode materials for supercapacitors
(2017-01-01)
Rattanamai, Songsak
;
Dulyaseree, Paweena
;
Wanchaem, Thanthumrong
;
Wongwiriyapan, Winadda
Manganese oxide nanosheet/manganese oxide thin film/multiwalled carbon nanotubes(s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs) were used as hybrid electrode materials for supercapacitor application. Supercapacitor performance based on these hybrid materials was optimized by varying morphologies of s-MnO<inf>x</inf>. Firstly, a MWNT paste was coated onto nickel (Ni) foam and subsequently f-MnO<inf>x</inf> was deposited onto the pre-coated MWNTs/Ni foam by galvanostatic (GS) mode of electrodeposition technique at a constant current of 1 mA/cm2 using 0.1 M KMnO<inf>4</inf> as a precursor with a fix deposited time of 5 min. Finally, s-MnO<inf>x</inf> was deposited onto the prepared f-MnO<inf>x</inf>/MWNTs/Ni foam by GS mode of electrodeposition technique at a constant current of 1 mA/cm2 using 0.1 M KMnO<inf>4</inf> as precursor with different deposited times of 10, 15 and 20 min. Each hybrid s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs electrode was characterized by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs electrode prepared by 15-min-deposited s-MnO<inf>x</inf> shows the highest specific capacitance. The capacitance improvement is attributed to the increase of electrode surface area.
Some of the metrics are blocked by your
consent settings
Facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube by two-step electrodeposition for supercapacitor electrode
(2017-01-01)
Wanchaem, Thanthamrong
;
Rattanamai, Songsak
;
Dulyaseree, Paweena
;
Khanchaitit, Paisan
;
Wongwiriyapan, Winadda
This work presents a facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube (MnO<inf>x</inf>/MWCNT) by two-step electrodeposition technique for supercapacitor electrode application. Firstly, MWCNT was deposited onto SS304 substrate by electrophoretic deposition at a constant voltage of 7 V for 5 min. MWCNT solution was prepared using sodium dodecylbenzenesulfonate (SBDS) as a surfactant. Next, MnO<inf>x</inf> was deposited onto the pre-deposited MWCNT/SS304 substrate by galvanostatic electrodeposition using 0.1 M manganese sulfate (MnSO<inf>4</inf>) solution as a precursor. The electrodeposition condition was set at a constant current of 1 mA/cm2 for 5-15 min. Nanosheet array of MnO<inf>x</inf> was formed uniformly on MWCNT. At the deposition time of 10 min, the thickness of MnO<inf>x</inf> nanosheet was approximately 40 nm. Hybrid MnO<inf>x</inf>/MWCNT was characterized its electrochemical properties by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical Impedance spectroscopy. Hybrid MnO<inf>x</inf>/MWCNT shows an improved specific capacitance of 267.03 F·g-1 with a series resistance of 5.17 Ω, surpassing electrode material with only MnO<inf>x</inf> or MWCNT. The high specific capacitance would be ascribed to the integration of MWCNT and MnO<inf>x</inf> functions. MWCNT may act as a platform for MnO<inf>x</inf> deposition, resulting in an increase in electrochemically active surface area of MnO<inf>x</inf>. The obtained results indicate that this two-step electrodeposition method allows tailor-made hybrid materials with nanoscale control without using harsh and toxic chemicals or high synthesis temperature.
1
Some of the metrics are blocked by your
consent settings
Electrodeposition of manganese oxide nanosheets as supercapacitor electrode materials
(2016-01-01)
Thanthamrong, Wanchaem
;
Songsak, Rattanamai
;
Paweena, Dulyaseree
;
Wirat, Jarernboon
;
Winadda, Wongwiriyapan
Manganese oxide (MnO<inf>x</inf>) thin films were prepared on stainless steel (SS) 304 by galvanostatic (GS) mode of electrodeposition technique using different precursors; 0.1 M potassium permanganate (KMnO<inf>4</inf>) and 0.1 M manganese sulfate (MnSO<inf>4</inf>) solutions. The electrodeposition condition was set at a constant current of 1 mA/cm2. Different precursors provide MnO<inf>x</inf> thin films with different morphologies. Using KMnO<inf>4</inf> as a precursor, the MnO<inf>x</inf> thin film was deposited (MnO<inf>x</inf>-K), while using MnSO<inf>4</inf> as a precursor, the MnO<inf>x</inf> nanosheets with a thickness of approximately 40 nm were formed (MnO<inf>x</inf>-S). XPS results evidence the formation of manganese oxide with different oxidation states composition by different precursors. Electrochemical measurements were carried out in a three-electrode setup using Pt and Ag/AgCl electrodes as counting and reference electrodes, respectively and 1M Na<inf>2</inf>SO<inf>4</inf> aqueous solution as electrolyte. MnO<inf>x</inf>-K at a deposition time of 10 min shows the highest specific capacitance of 233.55±19.01 F/g. The specific capacitance improvement of MnO<inf>x</inf>-K may be attributed to MnO<inf>x</inf> nanosheet structure which increases surface area of electrode.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results