The Experts below are selected from a list of 95799 Experts worldwide ranked by ideXlab platform
Ehsan Toyserkani - One of the best experts on this subject based on the ideXlab platform.
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surface modification of ti 6al 4v alloy using laser assisted Deposition of a ti si compound
Surface & Coatings Technology, 2008Co-Authors: M Alhammad, Shahrzad Esmaeili, Ehsan ToyserkaniAbstract:Abstract Pre-placed laser cladding and a mixture of 80 wt.%Ti–20 wt.%Si powder are used to produce hard coatings, containing Ti 5 Si 3 , on Ti–6Al–4V alloy substrate. The experiments are performed at three different laser scanning speeds for which a pulsed Nd:YAG laser and no shield gas are used. Optical microscopy, SEM, EDS and XRD methods, as well as microhardness measurement are used to examine the microstructural characteristics and hardness of the coating and coating–substrate interface. Crack-free coatings with metallurgical bonding to the substrate are obtained using 0.6 mm initial powder thickness. The coatings demonstrate solidified microstructures containing major dendritic and cellular Ti 5 Si 3 phase with interdendritic/intercellular mixtures containing α-Ti and Ti 3 Al phases. The results indicate that utilizing a higher scanning speed leads to a finer distribution of Ti 5 Si 3 phase and a higher hardness of coating, while a lower laser scanning speed may provide better control of the process. The effect of the laser scanning speed on the mechanisms of atom migration during cladding is discussed.
M Alhammad - One of the best experts on this subject based on the ideXlab platform.
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surface modification of ti 6al 4v alloy using laser assisted Deposition of a ti si compound
Surface & Coatings Technology, 2008Co-Authors: M Alhammad, Shahrzad Esmaeili, Ehsan ToyserkaniAbstract:Abstract Pre-placed laser cladding and a mixture of 80 wt.%Ti–20 wt.%Si powder are used to produce hard coatings, containing Ti 5 Si 3 , on Ti–6Al–4V alloy substrate. The experiments are performed at three different laser scanning speeds for which a pulsed Nd:YAG laser and no shield gas are used. Optical microscopy, SEM, EDS and XRD methods, as well as microhardness measurement are used to examine the microstructural characteristics and hardness of the coating and coating–substrate interface. Crack-free coatings with metallurgical bonding to the substrate are obtained using 0.6 mm initial powder thickness. The coatings demonstrate solidified microstructures containing major dendritic and cellular Ti 5 Si 3 phase with interdendritic/intercellular mixtures containing α-Ti and Ti 3 Al phases. The results indicate that utilizing a higher scanning speed leads to a finer distribution of Ti 5 Si 3 phase and a higher hardness of coating, while a lower laser scanning speed may provide better control of the process. The effect of the laser scanning speed on the mechanisms of atom migration during cladding is discussed.
Geun Young Yeom - One of the best experts on this subject based on the ideXlab platform.
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silicon nitride deposited by laser assisted plasma enhanced chemical vapor Deposition for next generation organic electronic devices
Applied Surface Science, 2021Co-Authors: Kihyun Kim, Ki Seok Kim, Ji Eun Kang, Geun Young YeomAbstract:Abstract Deposition of stoichiometric silicon nitride without damage and stress at low temperature using plasma enhanced chemical vapor Deposition (PECVD) is an important issue in the application to various areas such as microelectronics, micro-electromechanical system (MEMS), etc. In this study, the effects of laser assistance during PECVD (LAPECVD) of silicon nitride on the physical and chemical characteristics of deposited Si3N4 film were investigated. The LAPECVD assisted by 193 nm laser at 80 °C showed higher Deposition rates compared to PECVD due to the enhanced dissociation of the reactant gases. In addition, the stoichiometric ratio of N/Si and the residual stress of the deposited silicon nitride film were improved. When the silicon nitride was directly deposited on the organic light emitting diode (OLED) for thin film passivation, no electrical damage was observed for LAPECVD possibly due to the coverage of a thin silicon nitride layer on the OLED surface by laser assisted Deposition while conventional PECVD showed a damage of the device due to ion bombardment by direct exposure to plasma. We believe the LAPECVD system can be used for various next-generation microelectronic industries where high quality film Deposition with minimized damage during PECVD at low temperature is required.
Ki Seok Kim - One of the best experts on this subject based on the ideXlab platform.
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silicon nitride deposited by laser assisted plasma enhanced chemical vapor Deposition for next generation organic electronic devices
Applied Surface Science, 2021Co-Authors: Kihyun Kim, Ki Seok Kim, Ji Eun Kang, Geun Young YeomAbstract:Abstract Deposition of stoichiometric silicon nitride without damage and stress at low temperature using plasma enhanced chemical vapor Deposition (PECVD) is an important issue in the application to various areas such as microelectronics, micro-electromechanical system (MEMS), etc. In this study, the effects of laser assistance during PECVD (LAPECVD) of silicon nitride on the physical and chemical characteristics of deposited Si3N4 film were investigated. The LAPECVD assisted by 193 nm laser at 80 °C showed higher Deposition rates compared to PECVD due to the enhanced dissociation of the reactant gases. In addition, the stoichiometric ratio of N/Si and the residual stress of the deposited silicon nitride film were improved. When the silicon nitride was directly deposited on the organic light emitting diode (OLED) for thin film passivation, no electrical damage was observed for LAPECVD possibly due to the coverage of a thin silicon nitride layer on the OLED surface by laser assisted Deposition while conventional PECVD showed a damage of the device due to ion bombardment by direct exposure to plasma. We believe the LAPECVD system can be used for various next-generation microelectronic industries where high quality film Deposition with minimized damage during PECVD at low temperature is required.
Shahrzad Esmaeili - One of the best experts on this subject based on the ideXlab platform.
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surface modification of ti 6al 4v alloy using laser assisted Deposition of a ti si compound
Surface & Coatings Technology, 2008Co-Authors: M Alhammad, Shahrzad Esmaeili, Ehsan ToyserkaniAbstract:Abstract Pre-placed laser cladding and a mixture of 80 wt.%Ti–20 wt.%Si powder are used to produce hard coatings, containing Ti 5 Si 3 , on Ti–6Al–4V alloy substrate. The experiments are performed at three different laser scanning speeds for which a pulsed Nd:YAG laser and no shield gas are used. Optical microscopy, SEM, EDS and XRD methods, as well as microhardness measurement are used to examine the microstructural characteristics and hardness of the coating and coating–substrate interface. Crack-free coatings with metallurgical bonding to the substrate are obtained using 0.6 mm initial powder thickness. The coatings demonstrate solidified microstructures containing major dendritic and cellular Ti 5 Si 3 phase with interdendritic/intercellular mixtures containing α-Ti and Ti 3 Al phases. The results indicate that utilizing a higher scanning speed leads to a finer distribution of Ti 5 Si 3 phase and a higher hardness of coating, while a lower laser scanning speed may provide better control of the process. The effect of the laser scanning speed on the mechanisms of atom migration during cladding is discussed.
