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Samala S, Brahma GS, Swain T. Synthesis, characterization, and thermal property of phosphate-based cobalt mixture of non-calcined, calcined, and composite material. MONATSHEFTE FUR CHEMIE 2020. [DOI: 10.1007/s00706-019-02538-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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2
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Fabrication of a Thick Crystalline Al2O3 Coating with Insulation and High Thermal Conductivity via Anodic Oxidation and Subsequent Mic Arc Discharge Treatment. COATINGS 2020. [DOI: 10.3390/coatings10010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Amorphous Al2O3 coating with a thickness of 143 μm was firstly prepared by anodic oxidation, then the amorphous Al2O3 was transformed into crystalline Al2O3 through applying micro arc discharge. The crystal structure of the Al2O3 coatings was analyzed with an X-ray diffractometer. Results indicated that the coating consisted of amorphous and crystalline Al2O3. The microstructure of the coating was characterized by scanning electron microscopy, which showed that the coating had a compact structure. The thermal conductivity of the coating was 23.7 W/m·K, which is significantly higher than that of amorphous Al2O3 coating. The total and specific breakdown voltages of the coating were 3.85 kV and 26.92 kV/mm, which is suitable to apply for high power LED heat sink substrate.
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Choi I, Lee K, Lee CR, Lee JS, Kim SM, Jeong KU, Kim JS. Application of Hexagonal Boron Nitride to a Heat-Transfer Medium of an InGaN/GaN Quantum-Well Green LED. ACS APPLIED MATERIALS & INTERFACES 2019; 11:18876-18884. [PMID: 31037936 DOI: 10.1021/acsami.9b05320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Group III-nitride light-emitting diodes (LEDs) fabricated on sapphire substrates typically suffer from insufficient heat dissipation, largely due to the low thermal conductivities (TCs) of their epitaxial layers and substrates. In the current work, we significantly improved the heat-dissipation characteristics of an InGaN/GaN quantum-well (QW) green LED by using hexagonal boron nitride (hBN) as a heat-transfer medium. Multiple-layer hBN with an average thickness of 11 nm was attached to the back of an InGaN/GaN-QW LED (hBN-LED). As a reference, an LED without the hBN (Ref-LED) was also prepared. After injecting current, heat-transfer characteristics inside each LED were analyzed by measuring temperature distribution throughout the LED as a function of time. For both LED chips, the maximum temperature was measured on the edge n-type electrode brightly shining fabricated on an n-type GaN cladding layer and the minimum temperature was measured at the relatively dark-contrast top surface between the p-type electrodes. The hBN-LED took 6 s to reach its maximum temperature (136.1 °C), whereas the Ref-LED took considerably longer, specifically 11 s. After being switched off, the hBN-LED took 35 s to cool down to 37.5 °C and the Ref-LED took much longer, specifically 265 s. These results confirmed the considerable contribution of the attached hBN to the transfer and dissipation of heat in the LED. The spatial heat-transfer and distribution characteristics along the vertical direction of each LED were theoretically analyzed by carrying out simulations based on the TCs, thicknesses, and thermal resistances of the materials used in the chips. The results of these simulations agreed well with the experimental results.
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Affiliation(s)
| | - Kwanjae Lee
- Department of Physics , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Korea
| | | | - Joo Song Lee
- Institute of Advanced Composite Materials , Korea Institute of Science and Technology (KIST) , Wanju 55324 , Korea
| | - Soo Min Kim
- Institute of Advanced Composite Materials , Korea Institute of Science and Technology (KIST) , Wanju 55324 , Korea
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Hwang M, Chung W. Effects of a Carbon Nanotube Additive on the Corrosion-Resistance and Heat-Dissipation Properties of Plasma Electrolytic Oxidation on AZ31 Magnesium Alloy. MATERIALS 2018; 11:ma11122438. [PMID: 30513832 PMCID: PMC6317174 DOI: 10.3390/ma11122438] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/27/2018] [Accepted: 11/30/2018] [Indexed: 12/05/2022]
Abstract
Plasma electrolytic oxidation (PEO) coating was obtained on AZ31 Mg alloy using a direct current in a sodium silicate-based electrolyte with and without a carbon nanotube (CNT) additive. The surface morphology and phase composition of the PEO coatings were investigated through field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The corrosion-resistance properties of the PEO coatings were evaluated using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. Furthermore, the heat-dissipation property was evaluated by a heat-flux measurement setup using a modified steady-state method and Fourier transform infrared spectroscopy (FT-IR). The results demonstrate that, by increasing the concentration of CNT additive in the electrolyte, the micropores and cracks of the PEO coatings are greatly decreased. In addition, the anticorrosion performance of the PEO coatings that incorporated CNT for the protection of the Mg substrate was improved. Finally, the coating’s heat-dissipation property was improved by the incorporation of CNT with high thermal conductivity and high thermal emissivity.
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Affiliation(s)
- Myungwon Hwang
- Department of Materials Science and Engineering, Pusan National University, Busan 609-735, Korea.
| | - Wonsub Chung
- Department of Materials Science and Engineering, Pusan National University, Busan 609-735, Korea.
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Gao YY, Qiu F, Liu TS, Chu JG, Zhao QL, Jiang QC. Effects of Carbon Source on TiC Particles' Distribution, Tensile, and Abrasive Wear Properties of In Situ TiC/Al-Cu Nanocomposites Prepared in the Al-Ti-C System. NANOMATERIALS 2018; 8:nano8080610. [PMID: 30103408 PMCID: PMC6116243 DOI: 10.3390/nano8080610] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 11/20/2022]
Abstract
The in situ TiC/Al-Cu nanocomposites were fabricated in the Al-Ti-C reaction systems with various carbon sources by the combined method of combustion synthesis, hot pressing, and hot extrusion. The carbon sources used in this paper were the pure C black, hybrid carbon source (50 wt.% C black + 50 wt.% CNTs) and pure CNTs. The average sizes of nano-TiC particles range from 67 nm to 239 nm. The TiC/Al-Cu nanocomposites fabricated by the hybrid carbon source showed more homogenously distributed nano-TiC particles, higher tensile strength and hardness, and better abrasive wear resistance than those of the nanocomposites fabricated by pure C black and pure CNTs. As the nano-TiC particles content increased, the tensile strength, hardness, and the abrasive wear resistance of the nanocomposites increased. The 30 vol.% TiC/Al-Cu nanocomposite fabricated by the hybrid carbon source showed the highest yield strength (531 MPa), tensile strength (656 MPa), hardness (331.2 HV), and the best abrasive wear resistance.
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Affiliation(s)
- Yu-Yang Gao
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
| | - Feng Qiu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Qingdao Automotive Research Institute of Jilin University, No. 1, Loushan Road, Qingdao 266000, China.
| | - Tian-Shu Liu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
| | - Jian-Ge Chu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
| | - Qing-Long Zhao
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
| | - Qi-Chuan Jiang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988, Renmin Street, Changchun 130025, China.
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Han X, Huang Y, Gao Q, Yu M, Chen X. High Thermal Conductivity and Mechanical Properties of Nanotube@Cu/Ag@Graphite/Aluminum Composites. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b01567] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaopeng Han
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, P. R. China
- MOE Key Laboratory of Material Physics and Chemistry under Extrodinary Conditions, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, P. R. China
| | - Ying Huang
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, P. R. China
- MOE Key Laboratory of Material Physics and Chemistry under Extrodinary Conditions, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, P. R. China
| | - Qiao Gao
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, P. R. China
- MOE Key Laboratory of Material Physics and Chemistry under Extrodinary Conditions, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, P. R. China
| | - Meng Yu
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, P. R. China
- MOE Key Laboratory of Material Physics and Chemistry under Extrodinary Conditions, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, P. R. China
| | - Xuefang Chen
- Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, P. R. China
- MOE Key Laboratory of Material Physics and Chemistry under Extrodinary Conditions, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi’an 710072, P. R. China
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Li YC, Chang YH, Singh P, Chang LB, Yeh DH, Chao TY, Jian SY, Li YC, Tan CM, Lai CS, Chow L, Ying SP. RGB-Stack Light Emitting Diode Modules with Transparent Glass Circuit Board and Oil Encapsulation. MATERIALS 2018; 11:ma11030365. [PMID: 29494534 PMCID: PMC5872944 DOI: 10.3390/ma11030365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 11/16/2022]
Abstract
The light emitting diode (LED) is widely used in modern solid-state lighting applications, and its output efficiency is closely related to the submounts' material properties. Most submounts used today, such as low-power printed circuit boards (PCBs) or high-power metal core printed circuit boards (MCPCBs), are not transparent and seriously decrease the output light extraction. To meet the requirements of high light output and better color mixing, a three-dimensional (3-D) stacked flip-chip (FC) LED module is proposed and demonstrated. To realize light penetration and mixing, the mentioned 3-D vertically stacking RGB LEDs use transparent glass as FC package submounts called glass circuit boards (GCB). Light emitted from each GCB stacked LEDs passes through each other and thus exhibits good output efficiency and homogeneous light-mixing characteristics. In this work, the parasitic problem of heat accumulation, which caused by the poor thermal conductivity of GCB and leads to a serious decrease in output efficiency, is solved by a proposed transparent cooling oil encapsulation (OCP) method.
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Affiliation(s)
- Ying-Chang Li
- Green Technology Research Center, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Yuan-Hsiao Chang
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Preetpal Singh
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Liann-Be Chang
- Green Technology Research Center, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
- Department of Otolaryngology, Head and Neck Surgery, Chang Gung Memorial Hospital, Kweishan, Taoyuan 333, Taiwan.
- Department of Materials Engineering, Ming Chi University of Technology, Taishan, New Taipei City 243, Taiwan.
| | - Der-Hwa Yeh
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Ting-Yu Chao
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Si-Yun Jian
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Yu-Chi Li
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
| | - Cher Ming Tan
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
- Department of Materials Engineering, Ming Chi University of Technology, Taishan, New Taipei City 243, Taiwan.
- Department of Urology, Chang Gung Memorial Hospital, Kweishan, Taoyuan 333, Taiwan.
| | - Chao-Sung Lai
- Department of Electronic Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan.
- Department of Materials Engineering, Ming Chi University of Technology, Taishan, New Taipei City 243, Taiwan.
- Department of Nephrology, Chang Gung Memorial Hospital, Kweishan, Taoyuan 333, Taiwan.
| | - Lee Chow
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA.
| | - Shang-Ping Ying
- Department of Opto-Electronic System Engineering, Minghsin University of Science and Technology, Xinfeng Hsinchu 30401, Taiwan.
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