Browsing by Author "Chou, Chang-Pin"

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A New Technology of Scrape-Applied Method for the Manufacturing of MEA of Fuel-Cell System
(2008)
Wu, Shinn-Dar
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Lee, Chi-Hung
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Chou, Chang-Pin
;
Wang, Yen-Zen
;
機械工程學系
The technical transfer from electrode of lithium battery to MEA of fuel cells (including PEMFC and DMFC) were discussed in this study. There are three common methods for the manufacturing of lithium battery electrode; such as roller-applied method, scrape-applied method and spurt-applied method. The first two methods are the most commonly used method. This study was focused on the development of new scrape-applied equipment for lithium battery electrode. This new method was tested by measure the weight and thickness of dry electrode. The stability and reproducibility on electrode fabrication were also conducted by systematical data analysis. The results can offer an important basis to the future research on academic and commercial field.
Characteristics of Ni-Ir and Pt-Ir hard coatings surface treated by pulsed Nd:YAG laser
(2010-12-25)
Tseng, Shih-Feng
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
;
Chen, Ming-Fei
;
Lee, Chao-Te
The subjects of the presented paper are to develop a laser surface treatment technology for the protective coatings of glass-molding dies and to better understand the interaction between laser beam and materials coated on the die surface. A variety of alloy films, including Ir-25 at.% Pt. Ir-50 at.% Pt, Ir-75 at.% Pt. Ir-25 at.% Ni, Ir-50 at.% Ni, and Ir-75 at.% Ni compositions are deposited by the ion source assisted magnetron sputtering system (ISAMSS). A Cr layer that functioned as a buffer layer is deposited between the alloy film and die surface. After an alloy film and the buffer Cr layer were sequentially coated on tungsten carbide (WC) surface, Nd:YAG laser was directly applied in the writing process. The temperature profile of the film stack structure is simulated by ANSYS software. The surface roughness was analyzed by atomic force microscopy (AFM) to compare the coating surface roughness before and after the laser surface treatments. The treated coatings for oxidation prevention test were examined by energy dispersive x-ray spectrometry (EDS). Nanoindentation instrument was performed to evaluate microhardness and reduced modulus of the coatings. The cross-sectional structures between the hard coating layer and buffer layer were also inspected by a scanning electron microscope (SEM). The Pt-Ir and Ni-Ir film coatings are unable to withstand the working temperature over 1500 degrees C, which is considered for quartz molding process and hot embossing process. The films showed high roughness, low microhardness and low reduced modulus because the film oxidation occurred in a high working temperature process. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
Characterization and properties of infrared NLO crystals: AGeX(3) (A = Rb, Cs; X = Cl, Br)
(2008-06-15)
Lin, Zhi-Guang
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Tang, Li-Chuan
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Chou, Chang-Pin
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機械工程學系
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Department of Mechanical Engineering
innovative infrared nonlinear optical crystals AGeX(3) were synthesized. Their powder X-ray diffraction patterns demonstrated that they had rhombohedral structures with R3m (no. 160) space group symmetry (except RbGeBr3). Their structural distortion increased with Br content, but decreased with Rb content. The Kurtz powder methods revealed that the nonlinear optical efficiency of CsGeBr3 is 9.64 times that of rhombohedral CsGeCl3 and 28.29 times that of KDP; most importantly, AGeX(3) is phasematchable (except RbGeBr3). (C) 2008 Elsevier B.V. All rights reserved.
Characterization and properties of novel infrared nonlinear optical crystal CsGe(BrxCl1-x)(3)
(2008-04-07)
Lin, Zhi-Guang
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Tang, Li-Chuan
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Chou, Chang-Pin
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機械工程學系
;
Department of Mechanical Engineering
Innovative infrared nonlinear optical crystals CsGe(BrxCl(1-x))(3) were synthesized. Their powder X-ray diffraction patterns indicated that they had rhombohedral structures with (R3m, No. 160) space group symmetry. Their structural distortion increased with x The Kurtz powder techniques revealed that the nonlinear optical efficiency of CsGeBr3 is about 9.64 times larger than that of rhombohedral CsGeCl3 and 28.29 times larger than that of KH2PO4 (KDP); most importantly, CsGe(BrCl1-x)(3) is phase-matchable. The transparent infrared spectrum of rhombohedral CsGe(BrxCl1-x)(3) was extended to over 30 mu m and demonstrated its potential in the field of nonlinear optics and applicability in the infrared region.
Development of a Novel Rapid Manufacturing Process for Micro-Cylindrical Lens Array
(2011)
Huang, Chien-Yao
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Huang, Kuo-Cheng
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Chen, Jun-Cheng
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Chang, Keng-Souo
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Tseng, Shih-Feng
This paper proposed a novel method to fabricate micro-cylindrical lens array (mu-CLA) by using wire electrical discharge machining (WEDM) and precision glass molding (PGM) technique. Micro slits fabricated on the surface of tungsten carbide mold material with outline dimensions from 0.3mm to 2.1mm, the width and depth of 1 mm. The PGM processing parameters including width of slits, molding temperature, molding force and stroke were discussed. Moreover, the characteristics of mu-CLA were measured by contact profilometer. In addition, the relationship between the dimensions of the slit on tungsten carbide mold and the characteristics of mu-CLA also discussed.
Effect of activated TIG flux on performance of dissimilar welds between mild steel and stainless steel
(2011)
Kuo, Cheng-Hsien
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Tseng, Kuang-Hung
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Chou, Chang-Pin
;
機械工程學系
;
Department of Mechanical Engineering
The purpose of the present work was to investigate the effect of oxide fluxes on surface appearance, weld morphology, angular distortion, and weld defect obtained with activated tungsten inert gas (TIG) process applied to the welding of 6 mm thick dissimilar metal plates between JIS G3131mild steel and SUS 316L stainless steel. The CaO, Fe2O3, Cr2O3, and SiO2 fluxes used were packed in powdered form. The results indicated that the surface appearance of TIG welds produced with oxide flux formed residual slag. TIG welding with SiO2 powder can increase joint penetration and weld depth-to-width ratio, and therefore the angular distortion of the dissimilar weldment can be reduced. Furthermore, the defects susceptibility of the as-welded can also be reduced.
Effect of annealing treatment and nanomechanical properties for multilayer Si(0.8)Ge(0.2)-Si films
(2010-06-01)
He, Bo-Ching
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Wen, Hua-Chiang
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Lin, Meng-Hung
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Lai, Yi-Shao
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Wu, Wen-Fa
Multilayered silicon-germanium (SiGe) films consisting of alternating sublayers with different mechanical properties have been epitaxially deposited by an ultra-high vacuum chemical vapor deposition (UHV/CVD) system. We report engineering of the mechanical properties of SiGe multilayer films by a commercial nanoindenter. From annealing treatment, it consists of an ex situ thermal treatments in furnace (600 degrees C) and rapid thermal annealing (800 degrees C) system. Subsequent roughness and microstructure of SiGe multilayer films were characterized by means of atomic force microscope (AFM) and transmission electron microscopy (TEM). The annealing treatment not only produced misfit dislocations as a significant role in the critical pile-up event but also promoted hardness. The hardness of the films increased slightly and then gradually achieved a maximum value (from 12.6 +/- 0 4 GPa to 14.2 +/- 0.7 GPa) with increasing annealing temperature. This may be due to the relaxation effect from thermal annealing and is potential to provide the reliability behaviours to design periodical SiGe multilayer structure in further. (C) 2010 Published by Elsevier Ltd
Effect of dissimilar welding on mechanical properties of A7050 and A2024 aluminum alloy
(2011)
Chang, Chin-Chun
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Yang, Ji-Gang
;
Qi-Ling
;
Chou, Chang-Pin
;
機械工程學系
The effect of dissimilar welding of 7050/2024 aluminum alloy on mechanical properties and microstructure were analyzed and investigated. The post-welding heat treatments of weldments were carried out and recorded for microstructure, tensile test, hardness and fracture surface in different conditions. The experimental results indicate that the post-welding heat treatment, filler metal chose can increase the mechanical properties. The microstructure and fracture surface of dissimilar welding can evaluate the distribution of precipitation strengthening phase in fusion zone, heat: affected zone and its fracture type.
Effect of lath microstructure on the mechanical properties of flow-formed C-250 maraging steels
(2007-04-25)
Lee, Yen-Jung
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Kung, Ming-Chueh
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Lee, I-Kang
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Chou, Chang-Pin
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機械工程學系
A solution treated C-250 maraging steel tubing pre-form was cold forward flow-formed into a seamless tube to attain a 79% wall thickness reduction. Various heat treatments were then conducted on the tube to strengthen the material. This study found that although direct aging treatment could generate the tensile strength exceeded the specification's requirement in all the heat treatment attempts, the C-250 steel suffered loss of ductility in percentage elongation. Through "solution + aging" treatment, the steel's ductility was much improved and tensile properties can still meet the specification. The pre-treatment of high homogenization temperature could produce coarse lath martensitic microstructure and result in a decrease of the tensile strength of the C-250 steel. Furthermore, the C-250 steel also showed the presence of seemingly globular precipitates within the lath structure. Detailed discussion of mechanical properties obtained for each of the heat-treated steels in terms of microstructures and metallographic works was presented. (c) 2006 Elsevier B.V. All rights reserved.
Effect of repetition nanoindentation of GaN epilayers on a-axis sapphire substrates
(2011-05-01)
Lin, Meng-Hung
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Wen, Hua-Chiang
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Chang, Zue-Chin
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Wu, Shyh-Chi
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Wu, Wen-Fa
In this work, gallium nitride (GaN) epilayers were deposited on a-axis sapphire substrate by means of metal organic chemical vapor deposition (MOCVD). Berkovich nanoindentation was used to explore the repetition pressure-induced impairment of the GaN film. The observation of load-displacement vs stress-strain curves concludes that basal slip is implicated in the deformation on the A plane GaN. The increase in the hardness (H) and elasticmodulus (E) was determined from cyclic nanoindentation, and resulted in a crack due to the formation of incipient slip bands and/or the to-and-fro motion of mobile dislocation. It is indicated that the generation of individual dislocation and residual deformation of the GaN films are showed by CL mapping analysis. From the morphological studies, it is revealed that the crack was found by means of atomic force microscope (AFM) technique at nine loading/reloading cycles even after the indentation beyond the critical depth on the residual indentation impression. Copyright (C) 2010 John Wiley & Sons, Ltd.
Effect of strain relaxation of oxidation-treated SiGe epitaxial thin films and its nanomechanical characteristics
(2010-03-01)
He, Bo-Ching
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Wen, Hua-Chiang
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Chinag, Tun-Yuan
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Chang, Zue-Chin
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Lian, Derming
In this study, we examined the effect of high-temperature oxidation treatment on the SiGe epitaxial thin films deposited on Si substrates. The X-ray diffraction (XRD), atomic force microscopy (AFM), and nanoindentation techniques were employed to investigate the crystallographic structure, surface roughness, and hardness (H) of the SiGe thin films, respectively. The high-temperature oxidation treatment led to Ge pileup at the surface of the SiGe thin films. In addition, strain relaxation occurred through the propagation of misfit dislocations and could be observed through the cross-hatch pattern (800-900 degrees C) and SiGe islands (1000 degrees C) at the surface of the SiGe thin films. Subsequent hardness (H) measurement on the SiGe thin films by continuous penetration depth method indicated that the phenomenon of Ge pileup caused a slightly reduced H (below 50 nm penetration depth), while relaxation-induced defects caused an enhanced H (above 50 nm penetration depth). This reveals the influence of composition and defects on the structure strength of high-temperature oxidation-treated SiGe thin films. (C) 2009 Elsevier B.V. All rights reserved.
Evaluating nanotribological behavior of annealing Si(0.8)Ge(0.2)/Si films
(2011-12-01)
Wu, Ming-Jhang
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Wen, Hua-Chiang
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Wu, Shyh-Chi
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Yang, Ping-Feng
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Lai, Yi-Shao
In this study, the SiGe epilayers were created on silicon substrate by using ultra-high vacuum chemical vapor deposition (UHV/CVD) and followed by annealing procedures. The frictional behaviors of SiGe epilayers were subjected to nanoscratch techniques under a ramping load. Damage caused by scratching was examined by atomic force microscopy (AFM); the results showed that the pile-up phenomena were significant on both sides of the scratch in the case of SiGe epilayers, suggesting that the dynamic deformation behavior was dominated by cracking as ploughing occurred during scratching. In addition, the SiGe epilayers films with different annealed conditions exhibited the decrease in coefficient of friction (COF), indicating the higher shear resistance exist in annealed SiGe epilayers, which probably affect the film uniformity and device yield under IC process integration. (C) 2011 Elsevier Ltd. All rights reserved.
Evaluating nanotribological behavior of annealing Si0.8Ge0.2/Si films
(2011-12-01)
Wu, Ming-Jhang
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Wen, Hua-Chiang
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Wu, Shyh-Chi
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Yang, Ping-Feng
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Lai, Yi-Shao
In this study, the SiGe epilayers were created on silicon substrate by using ultra-high vacuum chemical vapor deposition (UHV/CVD) and followed by annealing procedures. The frictional behaviors of SiGe epilayers were subjected to nanoscratch techniques under a ramping load. Damage caused by scratching was examined by atomic force microscopy (AFM); the results showed that the pile-up phenomena were significant on both sides of the scratch in the case of SiGe epilayers, suggesting that the dynamic deformation behavior was dominated by cracking as ploughing occurred during scratching. In addition, the SiGe epilayers films with different annealed conditions exhibited the decrease in coefficient of friction (COF), indicating the higher shear resistance exist in annealed SiGe epilayers, which probably affect the film uniformity and device yield under IC process integration. (C) 2011 Elsevier Ltd. All rights reserved.
Evaluating the abrasive wear of Zn(1-x)Mn(x)O heteroepitaxial layers using a nanoscratch technique
(2010-08-01)
Chang, Yu-Ming
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Wen, Hua-Chiang
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Yang, Chu-Shou
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Lian, Derming
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Tsai, Chien-Huang
In this study, we used nanoscratch techniques under a ramping load to evaluate the abrasive wear of Zn(1-x)Mn(x)O epilayers (0 <= x <= 0.16) grown through molecular beam epitaxy (MBE) on sapphire substrates. We analyzed the surface roughness and damage using atomic force microscopy (AFM) and nano-indenter techniques. The scratched surfaces of the Zn(1-x)Mn(x)O epilayers were significantly different for the various Mn compositions. AFM imaging of the Zn(1-x)Mn(x)O films revealed that pileup phenomena were important on both sides of each scratch. During the scratching process, we found that cracking dominated in the case of Zn(1-x)Mn(x)O films while ploughing; also we observed lower values of the coefficient of friction and shallower penetration depths for the films upon increasing the Mn content (x) from 0 to 0.16, suggesting that higher Mn contents provided the Zn(1-x)Mn(x)O epilayers with higher shear resistances, enhanced by the presence of MnO bonds. (C) 2010 Elsevier Ltd. All rights reserved.
Evaluating the abrasive wear of Zn1-xMnxO heteroepitaxial layers using a nanoscratch technique
(2010-08-01)
Chang, Yu-Ming
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Wen, Hua-Chiang
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Yang, Chu-Shou
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Lian, Derming
;
Tsai, Chien-Huang
In this study, we used nanoscratch techniques under a ramping load to evaluate the abrasive wear of Zn1-xMnxO epilayers (0 <= x <= 0.16) grown through molecular beam epitaxy (MBE) on sapphire substrates. We analyzed the surface roughness and damage using atomic force microscopy (AFM) and nano-indenter techniques. The scratched surfaces of the Zn1-xMnxO epilayers were significantly different for the various Mn compositions. AFM imaging of the Zn1-xMnxO films revealed that pileup phenomena were important on both sides of each scratch. During the scratching process, we found that cracking dominated in the case of Zn1-xMnxO films while ploughing; also we observed lower values of the coefficient of friction and shallower penetration depths for the films upon increasing the Mn content (x) from 0 to 0.16, suggesting that higher Mn contents provided the Zn1-xMnxO epilayers with higher shear resistances, enhanced by the presence of MnO bonds. (C) 2010 Elsevier Ltd. All rights reserved.
Evaluation of the nanoindentation behaviors of SiGe epitaxial layer on Si substrate
(2010-01-01)
He, Bo-Ching
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Cheng, Chun-Hu
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Wen, Hua-Chiang
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Lai, Yi-Shao
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Yang, Ping-Feng
In this paper, ultra-high vacuum chemical vapor deposition (UHV/CVD) was employed to synthesize silicon-germanium (SiGe), and sequence to endure annealing treatment. Morphological characterization, roughness, and microstructural morphology were observed by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The elements distribution, crystallographic, and nanomechanical behavior were carried out using energy-dispersive Xray spectroscopy (EDS) mapping technique, X-ray diffraction (XRD), and nanoindentation technique. The annealing treated SiGe leads to the 2D germanium segregation on the surface. The phenomenon is interpreted in terms of dislocation-induced structural changes in annealing treatment, Thus, the dislocation propagation in the microstructure was observed. Subsequently hardness and elastic modulus were increased because of a comparatively unstable microstructure after annealing treatment. (C) 2009 Elsevier Ltd. All rights reserved.
Fabrication of a double-sided micro-lens array by a glass molding technique
(2011-08-01)
Huang, Chien-Yao
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Hsiao, Wen-Tse
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Huang, Kuo-Cheng
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Chang, Keng-Souo
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Chou, Hsiao-Yu
In recent years, micro-lens arrays (MLAs) have become important elements of optical systems. One function of MLAs is to create a uniform intensity of light. Compared with one-sided MLAs, the uniformity of light intensity increases with double-sided MLAs. MLAs fabricated by glass can be used in higher temperature environments or in high-energy systems. Glass-based MLAs can be fabricated by laser machining, photolithography, precision diamond grinding process and precision glass molding (PGM) technologies, but laser machining, photolithography and precision diamond grinding process technologies are not the perfect approach for mass production. Therefore, this paper proposes a method to fabricate a mold by laser micro-machining and a double-sided MLA by a PGM process. First, a micro-hole array was fabricated on the surface of a silicon carbide mold. A double-sided MLA using two molds was then formed by a PGM process. In this paper, the PGM process parameters including molding temperature and molding force are discussed. Moreover, the profile of a double-sided MLA is discussed. Finally, a double-sided MLA with a diameter of 20 mm, and lenses with a height of 52 mu m, a radius of 851 mu m and a pitch of 700 mu m were formed on glass.
Fabrication of fresnel lens by glass molding technique
(2013-03-01)
Huang, Chien-Yao
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Chen, Chun-Chieh
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Chou, Hsiao-Yu
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Chou, Chang-Pin
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機械工程學系
In this paper, we describe the fabrication of a Fresnel lens with a diameter of 15mm by a glass molding technique. Tungsten carbide and K-CSK120 were used as the materials of the mold and lens, respectively. The optimal parameters determined for the molding process included a molding temperature of 560 A degrees C, a molding force of 300 N, a temperature holding time of 180 s, and a cooling rate of 18.5 A degrees C/min.
Field emission characteristics of carbon nanotubes post-treated with high-density Ar plasma
(2010-01-15)
Wang, Wen-Pin
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Wen, Hua-Chiang
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Jian, Sheng-Rui
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Cheng, Huy-Zu
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Jang, Jason Shian-Ching
The field emission characteristics of carbon nanotubes (CNTs) grown by thermal chemical vapor deposition (CVD) and subsequently surface treated by high-density Ar plasma in an inductively coupled plasma reactive ion etching (ICP-RIE) with the various plasma powers were measured. Results indicate that, after treated by Ar plasma with power between 250 and 500 W, the emission current density of the CNTs is enhanced by nearly two orders of magnitude (increased from 0.65 to 48 mA/cm(2)) as compared to that of the as-grown ones. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to investigate the structural features relevant to the modified field emission properties of CNTs. The SEM images of CNTs subjected to a 500 W Ar plasma treatment exhibit obvious damages to the CNTs. Nevertheless, the turn-on fields decreased from 3.6 to 2.2V/mu m, indicating a remarkable field emission enhancement. Our results further suggest that the primary effect of Ar plasma treatment might be to modify the geometrical structures of the local emission region in CNTs. In any case, the Ar plasma treatment appears to be an efficient method to enhance the site density for electron emission and, hence markedly improving the electric characteristics of the CNTs. (C) 2009 Elsevier B.V. All rights reserved.
Fracture responses of microstructures of electron beam-welded D6AC
(2012-07-20)
Wu, Shyh-Chi
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Wen, Hua-Chiang
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Wu, Ming-Jhang
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Chou, Chang-Pin
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機械工程學系
In this study, D6AC steel was produced from flow forming (wall thickness reduction: 67%) and then it was subjected to electron beam welding and tempering treated. We characterized the specimens in terms of their microstructures and nanotribological properties. After tempering treatment at 315 degrees C, the yield strength increased from 381 to 1334 MPa and the percentage elongation increased remarkably from 0.5 to 7.8%. We performed these mechanical studies for the samples subjected to each set of experimental conditions, and determined the tribological characteristics from the heat-affected zone and the fusion zone. Lower degrees of adhesion reflected the presence of interlinks and rearrangements of indenter tip at lateral force that have been responsible for fluctuations in the coefficients of friction. (C) 2012 Elsevier Ltd. All rights reserved.