ICMCTF2007 Session GP: Symposium G Poster Session

Thursday, April 26, 2007 5:00 PM in Room Town & Country

Thursday Afternoon

Time Period ThP Sessions | Topic G Sessions | Time Periods | Topics | ICMCTF2007 Schedule

GP-1 Elucidating the Characteristics of Plasma Spraying Boron Carbide Coatings Applied for High-Density Plasma Devices W.H. Liao, W.T. Hsiao (Industrial Technology Research Institute, Taiwan); C.Y. Su (National Taipei University of Technology, Taiwan); F.S. Shieu (National Chung Hsing University, Taiwan); M.S. Leu (Industrial Technology Research Institute, Taiwan) This research attempts to apply boron carbide coatings for the next generation plasma devices, e.g., plasma reactors that are used in semiconductor and thin film transistor liquid crystal display (TFT LCD) industries. Besides, the essential specification of boron carbide coatings onto device in high-density plasma (HDP) environment is necessitated against plasma-induced damage, i.e., radiation and reactive ion etching, etc. In this paper, the boron carbide coatings were deposited on anodized aluminum substrate by plasma spraying deposition and investigated the various properties of as-sprayed coatings including primarily B₄C crystalline phase identified by X-ray diffraction (XRD). Furthermore, predicting the service life of B₄C coatings and simulation experiments have been studied. Results of this study indicate that B₄C coatings reveal a stronger protective effect than established anodized alumina coatings.
GP-2 Microfabrication and Characterization of Metal Embedded Thin-Film Thermomechanical Microsensors for Application in Hostile Manufacturing Environments V.V. Ravi Kiran (Osmania University, India); T. Sri Krishna (CMR College Of Engineering And Technology, India) Effective monitoring and diagnosis of manufacturing process is of critical importance. If critical manufacturing process conditions are continuously monitored, problems can be detected and solved during the processing cycle. But that technology is still not available. Microfabricated thin-film thermocouples and strain gauges are attractive for their small sizes and fast response. It's nothing less than a challenge to fabricate them and embed them into the metals. This paper deals with the fabrication, embedding and characterization of thin-film thermocouples and strain gauges. Thin-film thermocouples on stainless steel substrates were calibrated to elevated temperatures. The behavior of thin-film gauges is also studied. The metal embedded sensors showed good accuracy, sensitivity and linearity that matched the commercial performance required. They are promising for hostile manufacturing.
GP-3 Microstructures and Tribological Characteristics of Cr-Zr-N Thin Film Coatings S.Y. Lee, B.Y. Lee, G.S. Kim (HanKuk Aviation University, Korea) CrN together with TiN has been the most extensively studied and frequently used in various industries due to its high thermal stability and good wear resistance as well as superior corrosion resistance. However, in spite of its excellent properties, CrN still shows inadequate properties for some applications such as high speed machining and high temperature conditions above 700 e system with the addition of other elements into binary system was explored. It is well known that ternary nitride coatings exhibit usually superior mechanical and chemical properties compared with binary nitride films. And recently, extensive reports have been made on various Cr based ternary nitride coatings such as Cr-Ti-N, Cr-Al-N, Cr-W-N and Cr-Si-N. In this work, Cr_1-xZr_xN films were synthesized in order to improve the mechanical properties of CrN coating and their crystalline structure, morphology and mechanical properties as a function of Zr content were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation and wear tests under various humidity conditions. The experimental results reveal that the structure and mechanical properties of films were found to depend strongly on the Zr content. As the Zr content increases, the more dense and compact microstructure is developed and the surface roughness is highly decreased. Also, the mechanical properties including hardness (maximum hardness: 34 GPa) and wear property are largely improved in comparison with CrN film. These CrZrN films showed excellent tribological properties under high humidity conditions, even better than DLC coatings. Detailed analysis results will be presented.
GP-5 The Effect of Inductively Coupled Plasma (ICP) on the Heat Flux to the Substrate During ICP Sputtering J.N. Kim, H.Y. Lee, J.J. Lee (Seoul National University, Korea) The heat flux to the substrate during inductively coupled plasma (ICP) sputtering was determined by a home-made thermal probe. The thermal probe was calibrated by linear fitting of the temperature gradient versus bias curve, which was induced in the thermal probe. The heat flux was approximately 50mW/cm^2 in the absence of ICP, while it was in the range between 100 and 1400mW/cm^2 with ICP, depending on the ICP power and pressure. Under same deposition conditions, the heat flux increased by five times when the ICP power was turned on to 100W. The heat flux increased with increasing the pressure, which indicates that sputtered atoms are not the main source of the heat transfer. In the ICP sputtering system, electrons and ions in ICP is rather the main source for the heat flux. It is supposed that the heat flux is one of the important process parameters by ICP assisted deposition.
GP-7 High Power Laser Diode Surface Treatment of Aluminium Matrix Composites J. Rams (Rey Juan Carlos University, Spain); A. Pardo, R. Arrabal, F. Viejo (Universidad Complutense de Madrid, Spain); A.J. Lopez (Rey Juan Carlos University, Spain); M.C. Merino (Universidad Complutense de Madrid, Spain); A. Ureña (Rey Juan Carlos University, Spain) Aluminium alloys and aluminium matrix composites are interesting materials because of their good mechanical and chemical properties, but when they are obtained by a casting route porosity, particle clustering and intermetallic precipitates degrade their mechanical and chemical properties. Several processing techniques allow enhancing the behaviour of these materials but only those based on surface engineering seem to be competitive. We have used a high power laser diode (HPLD) to treat the surface of A361 aluminium alloys and A360 aluminium matrix composites reinforced with SiC particles. This type of laser is cheaper than other ones for equivalent laser light power, and its compactness, maintenance and energy consumption makes them the best option in industrial applications if suitable material properties are obtained. We have controlled the laser power density, laser energy input and laser speed to produce the melting and rapid solidification of the outer part of the samples to modify their microstructure avoiding the appearance of aluminium carbide in the composites. For the best treatments grain size reduces, intermetallic precipitates dissolve and, in the case of composites, particles get homogeneously distributed. Microhardness measurements show increases in hardness above 50% in the case of composites and about 80% in aluminium alloys. Electrochemical corrosions test show a strong change in their behaviour, and a wide gap of 200 mV appears between the corrosion potential and the pitting one. The origin of this behavior seems to be in the formation of an amorphous layer on the top of the sample, as it has been determined by X-ray diffraction analysis.
GP-8 Secondary Ion Efficiency Enhancement in SIMS by Electron Beam Irradiation W.-C. Lee, C.-C. Lin, J. Hwang (National Tsing Hua University, Taiwan) Electron beam irradiation was demonstrated to be able to enhance the ¹¹B signal for a shallow p/n junction implanted with BF₂⁺ ions, which ionized the sputtered radicals or neutrals in a post-ionization process followed by a traditional secondary ion mass spectrometry (SIMS) operation. Various species were enhanced at a different enhancement factor due to different ionization potentials. When the electron beam current was kept at 100 µA, the ¹⁹F signal was greatly enhanced by 39 times and the ¹¹B signal was slightly enhanced by a factor of ~ 50 %. The enhancement approximately increased with electron beam current. The detection limit of the ¹¹B signal in a shallow p/n junction was lowered from 6.72 x 10¹⁶ to 1.31 x 10¹⁶ atom/cm³ when the electron beam current increased from 0 to 180 µA. A post-ionization mechanism was proposed in explaining the enhancement of SIMS signals.
GP-9 Correlation Between Wetting and Tribological Performance of CrAlN, ZrC_g and WC/C Films with Different Lubricants K. Bobzin, R. Nickel, N. Bagcivan, K. Yilmaz (RWTH Aachen University, Germany) More and more PVD coated components are being utilized in many types of industrial machines. These components are often subjected to work with lubricants and additives, which are only optimised for the metallic surfaces. The interactions between the metallic surfaces and lubricants with additives are different than the PVD coated ones. It is well known that chemical reactions take place between the metallic surfaces and additives, which change the surface function and provide application specific characteristics. Due to the chemically inert behaviour of the most of PVD films, it is not possible to make the same statement. For such PVD films, the surface free energy is the characteristic factor for the interfacial interactions like wetting, adhesion and adsorption. In this research the surface free energy of three different types of lubricants, with and without additives and the PVD coated alloyed Steel 16MnCr5 samples are examined by using drop shape analysis. The lubricants mineral oil, PG (Poly-Glycol), PAO (Poly-Alpha-Olefin), the additives ZDDP (Zinc Dialkyl Dithiophosphates), Mo and the coatings CrAlN, ZrC_g, WC/C are the elements of the research matrix. In order to evaluate how the wetting behaviour of the lubricants correlate with the tribological performance of the PVD films, the spreading coefficient S is calculated for each film-lubricant pair and all these pairs are tested in a Ball-On-Disc Tribometer. The wear rate is determined and the chemical composition on the wear track examined by XPS. The results of the wetting behaviour and tribological performance are compared.
GP-10 Definition of Cavitation Erosion Stages in Surface-Treated Systems using 3d Surface Topography Analyses C. Godoy, R.D. Mancosu, P.J. Modenesi (Universidade Federal de Minas, Brazil); J.C. Avelar-Batista (Tecvac Ltd., Brazil) In a previous investigation into the cavitation erosion resistance of duplex (plasma nitrided + PAPVD Cr-N-coated) and non-duplex (non-nitrided but PAPVD Cr-N-coated) systems, different cavitation erosion stages from those described in the ASTM G32-03 standard could be established through mass loss measurements. Although an incubation period and a final accelerated stage still occurred, some intermediate stages could be associated with cavitational wear of individual modified layers. The cavitation stages were named incubation period, coating erosion period, plasma nitriding erosion period, erosion period of substrate that had been previously surface-modified and a final accelerated stage. In this work, 3D surface topography analyses were used to validate these cavitation stages by plotting several surface roughness parameters, such as amplitude and the Sk set of functional parameters, as a function of the cavitation erosion time. Measurements of surface waviness led to the definition of a crater period that had negligible mass loss and occurred prior to the incubation stage defined in the ASTM G32-03 standard. In this standard, the incubation period is defined as the initial stage of the cumulative erosion rate-time curve in which the erosion rate is zero or negligible in comparison to that of subsequent stages. During the crater stage defined in this work, the amplitude parameters remained constant and, only after this period, craters (pits) could be seen in topographical images of the surface. The results indicated that changes in surface topography occurred before mass variations could be detected using high-precision scales. For the duplex system, the crater stage lasted for longer cavitation times than the incubation period, as material loss initially took place by cohesive failure without generating areas of localised damage. This finding reinforced the fundamental role played by plasma nitriding in improving the cavitation erosion performance.
GP-11 Preparation of BaTiO₃ Films by a PVD and Hydrothermal Duplex Technique P.-H. Chan, F.-H. Lu (National Chung Hsing University, Taiwan) Barium titanate (BaTiO₃) films were prepared using a physical vapor deposition and hydrothermal duplex technique. Titanium films were firstly deposited on Si substrates by D.C. magnetron sputtering. The grain sizes of titanium films ranged from 40 to 80 nm and the thickness was about 350 nm. Bulk titanium with grain sizes of about 50 µm was also used for comparison. Subsequently, titanium-coated Si as well as bulk titanium specimens were soaked in a mixture of Ba(CH₃COO)₂ and NaOH alkaline solution at temperatures below 100°C. The hydrothermal temperature and time were varied to investigate the growth of films. X-ray diffraction results show cubic BaTiO₃ films were successfully formed on titanium-coated substrates. Field-emission scanning electron microscopy revealed that BaTiO₃ films exhibiting a sphere-like morphology with grain sizes ranging from 70 to 300 nm. BaTiO₃ films could not be formed below 55°C. It is noteworthy that the growth rate of BaTiO₃ on titanium-coated substrates is much faster than that on bulk titanium. The dielectric properties of the films were measured. The formation mechanism of BaTiO₃ films were discussed as well.
GP-12 Remote Plasma Etching of Amorphous Silicon using Pin to Plate Dielectric Barrier Discharge S.J. Kyung, J.B. Park (Sungkyunkwan University, Korea); Y.H Lee (Samsung, Korea); J.H. Lee, G.Y. Yeom (Sungkyunkwan University, Korea) An atmospheric pressure plasma was generated with a modified dielectric barrier discharge having the power electrode composed of multi-pins (that is, pin-to-plate type) instead of conventional blank plate (that is, DBD-type) and its discharge characteristics and the amorphous silicon etch characteristics were compared with those by the DBD-type. The etch characteristics of fluorine-based gas such as NF₃, SF₆ and CF₄ have been studied. The pin-to-plate type showed higher discharge current and higher power consumption than the DBD-type at a given voltage , therefore, the pin-to-plate type appeared to be more efficient compared to the conventional DBD-type. Also, when amorphous silicon etch rate was investigated, the pin-to-plate showed higher etch rates compared to the DBD-type in various N₂/NF₃, SF₆, CF₄ mixtures. Using a mixture of 200sccm of NF₃ and 40slm of N₂, the maximum amorphous silicon etch rate of 65nm/sec could be obtained with the pin-to-plate type, at 18kV of AC voltage for the electrode size of 170mm x 100mm.
GP-13 Wear and Fatigue Properties Of Duplex-Treated Ti₆Al₄V Coatings under Conditions Of Reciprocating-Sliding and Rotating-Bending Z. Mohd Rosli, A. Leyland, A. Matthews (University of Sheffield, United Kingdom) Titanium and its alloys are used widely and are known for their many desirable properties such as corrosion resistance, biocompatibility and high specific strength. However, their tribological behaviour is generally poor relative to that of steel. Despite the attractive strength-to-weight ratio, Ti and its alloys are known to exhibit poor wear resistance, yet there is increasing demand for them to be used in moving parts for weight-saving purposes, particularly in the aircraft industry. PVD coatings are potentially beneficial, but the alloys generally provide insufficient load support. Modifying the surface through duplex processing is one of the choices available to improve the wear resistance of Ti-alloys (eg. nitriding + coating). In this study, the wear and fatigue behaviour of duplex-treated Ti₆Al₄V coatings under reciprocating-sliding testing and rotating-bending are investigated. The wear mechanisms are studied based on examination of the worn surfaces (as well as the wear debris) using Optical Microscopy, SEM and EDS and the results and their implications for practical applications are also discussed.
GP-14 Influence of the Heat Treatment Temperature on the Corrosion Resistance of a Ni-P Autocatalytic Coating O.A. León, D. Pacheco, L.E. Gil (Polytechnic Experimental National University (UNEXPO), Venezuela) Dynamic polarization and polarization resistance experiments at room temperature were performed, using a potentiostat, in order to study the corrosion resistance of a Ni-P conventional autocatalytic coating with 10 weight percent of P in as deposited and heat treated conditions (200, 300 and 400°C by a hour). Substrate used for the autocatalytic deposition was AISI 1045 steel. The coating with 10 weight percent of P was obtained by using a sodium hypophosphite based autocatalytic bath with enhanced agitation. Scanning Electron Microscopy and EDX techniques were employed for to study the morphology and chemical composition of the corrosion products. Knoop microhardness, structure, roughness, thickness and corrosion resistance of the coating for all experimental conditions are reported. The results obtained indicate that the coating heat treated at 400°C by a hour presents the lower corrosion resistance with a massive cracking after the corrosion tests.
GP-15 Effects of the Electrodeposition Parameters on Adhesion and Wear Resistance of Tin - Nickel Coatings H. Jimenez (Fundacite Guayana, Venezuela); L.E. Gil (Polytechnic Experimental National University (UNEXPO), Venezuela); E. Puchi (Universidad Central de Venezuela); M.H. Staia (Universidad Central de Venezuela, Veneauela) The present research is performed in order to determine the influence of both the chemical composition of the bath and the current density on the adhesion and wear resistance of the tinâ?"nickel coatings deposited on steel plate substrate. The micro-scratch test method (CSEM) was employed to evaluate the coating adhesion. Three scratches were performed at progressive load and the subsequent observation of the surface damage by means of an optical microscope allowed the determination of the critical load, defined as the smallest load at which some recognizable adhesive failure event occurs. The composite hardness of the system was determined by using Vickers indentation as function of the relative indentation depth and the absolute hardness of the coatings was determined by using a model published previously in the literature. The evaluation of the wear resistance was carried out through a wear accelerated test, without lubricant, under ball-on-disc configuration, using a ball of AISI 52100 steel as a static counterpart. The wear trace morphology was studied by Scanning Electronic Microscopy (SEM) technique coupled with the energy dispersive X-Ray analysis (EDS). The results indicated that the tin-nickel coatings obtained when using the chloride-fluoride bath have a higher adhesion to the steel substrate compared to those coatings which were obtained by using the pyrophosphate bath, irrespective to the current density value employed during deposition. The tribological performance of the former coatings was also higher, and wear volume between 0,03 to 0,05 mm3 was determined for these coatings.
GP-16 Formation and Characterization of Cr-DLC/Cu-DLC Multi-Layers Coating Using Filtered Cathodic Arc Evaporation J.-Y. Jao, L.-S. Chang (National Chung Hsing University, Taiwan); S. Han (National Taichung Institute of Technology, Taiwan); H.C. Shih (National Tsing Hua University, Taiwan) Chromium and copper-doped diamond-like carbon (DLC:Cr:Cu) films were deposited on SKH 51 tool steel. We have prepared multi-layers of DLC:Cr and DLC:Cu by filtered cathodic arc evaporation process using Cr_0.50Cu_0.50-target arc sources to provide Cr and Cu in the DLC. Acetylene reactive gases ware also activated at pressure 10 to 25 mtorr and temperature fixed at 180°C to provide DLC. The resulting DLC:Cr:Cu film contains Cr_xCu_y as well as Cr_xC_y nanoparticles which are vital for the film mechanical propertied. The crystal structure was investigated using x-ray diffraction (XRD) and transmission electron microscopy. While the surface morphology and chemical composition were studied by field emission scanning electron microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy. The process parameters were compared by studying various mechanical properties of the films such as microhardness, adhesion residual stress etc. The result of this process enhances the DLC:Cr:Cu composite coatings for high toughness and lower friction coefficient (0.12). The profiles of I_D/I_G (Raman) and sp³/sp² (XPS) ratios are corresponding to the change of microhardness profile as varying the hydrocarbon gases (C₂H₂) pressure.
GP-17 High-Speed Deposition of Amorphous Carbon Films on Inner Surface of Metal Tube With Surface Wave-Excited High-Density Plasma H. Kousaka, S. Kishine, N. Umehara (Nagoya University, Japan) Recently, diamond-like carbon (DLC) films have been carefully watched owing to their preferable mechanical properties. In particular, thin film coating of DLC has large possibility of wide use in machine parts. However, application of DLC is often rejected in design processes owing to its high coating cost, which is related to plasma/ion processes employed. One of the main reasons for the cost rise is considered to be low coating speed due to the use of conventional low-density plasmas (plasma electron density, n_e<10¹⁰ cm³), which is typically generated by applying either DC or RF bias between a substrate and ground. Therefore, high-speed DLC coating method with high-density plasma (n_e>10¹¹ cm³) is being developed for driving down the coating cost. However, in the case of coating the inner surface of tubular shapes, we often have no choice but to use conventional plasmas, because it is typically difficult to generate high-density plasma in such inner surfaces. Thus, the appearance of high-speed DLC coating method has been strongly desired for the inner surface of tubular shapes such as pipes, injection molds, and tube parts of medical devices. Thus, in this study, we proposed a new method with surface wave-excited high-density plasma, where a quartz tube antenna was employed to deposit DLC film on the inner surface of a stainless-steel pipe. As a result of our experiments, the obtained highest value of average deposition rate was 5.8 µm/h with an input microwave power of 200 W at a total gas pressure of 40 Pa. Here, the gas flow rates of Ar, CH₄, and TMS were 10, 10, and 2 sccm, respectively, and the distance between the quartz surface and the substrate pipe was 19 mm. This work was supported by Industrial Technology Research Grant Program in '03 from New Energy and Industrial Technology Development Organization (NEDO) of Japan [Fund No. 03A27007a].
GP-18 Fabrication and Thermal Analysis of the Cu/Diamond/Cu Thermal Spreading Device T.F. Young (National Sun Yat-Sen University, Taiwan, R.O.C.); J.H. Hsu (National Sun Yat-Sen University, Taiwan) With the excellent thermal conductivity, diamond is the best candidate for the thermal spreader materials. However, due to different thermal expansions the adhesion of metal on diamond is rather poor for applications. In this work we report the experimental results of fabrication and thermal analysis of a new developed copper/diamond/copper device for thermal spreading. A 1.2 µm Cu thin film has been deposited on CVD diamond thin film sample by r. f. sputtering and then electroplating the Cu film to 100 µm thickness. Before deposition a cleaning process with Ar plasma for 30 min has performed. Deposition temperature was studied to optimize the adhesion of Cu on diamond. The adhesion of Cu on diamond was analyzed by scratch and pull off tests. The critical load of Cu on diamond reveals a satisfied adhesion to resist the thermal stress at high temperature of 300°C. A thermal fatigue experiment of 1000 times cyclic heating and cooling treatments between 200 and 80°C, respectively, has been carried out. The adhesion of Cu on diamond did not show significant degradation after the fatigue test. The thermal spreader was performed by removing the backside silicon substrate and sputtering Cu films on diamond again. Thermal conductivity of this device was then measured by using a heat resistor mounted on it. This thermal spreader device reveals an excellent thermal conductivity for larger than 6.5 W/cm². An application for power LED working with 6W has demonstrated.
GP-19 Effect of Surface Modified Carbon Nanotubes and Organic Vehicles on the Dispersion and Emission Properties of the Paste for Display H.-F. Wei, G.-H. Hsiue (National Tsing Hua University, Taiwan); C.-Y. Liu (Industrial Technology Research Institute, Taiwan) The different surface-modified carbon nanotube (CNT) and organic vehicles were used to synthesize CNT paste for back-light unit (BLU). The surface of CNT was modified by the chemical syntheses of a series of alkoxide compounds with acid-treated CNT. These new CNT was characterized by FTIR and XPS. The dispersion, thermal and emission characteristics of the CNT paste with different components were investigated. CNT emitter was fabricated by screen-printing technique. The dispersion effect was maximized by incorporating sodium ethoxide to acid-treated CNT in the PMMA resin. The thermal stability was slightly decreased as the surface of CNT was esterified. The current density increases by 5 times in magnitude when the PMMA was used as the organic vehicle.
GP-20 Synthesis and Electrochemical Properties of High Energy Li-Ion Battery with LiNi_0.8Co_0.15Mn_0.05O₂ as Cathode Material C.-L. Lu, H.C. Shih (National Tsing Hua University, Taiwan); J.M. Chen (Industrial Technology Research Institute, Taiwan) We can successfully synthesize LiNi_0.8Co_0.15Mn_0.05O₂ by heat-treatment of LiOH and Ni_0.8Co_0.15Mn_0.05(OH)₂ from manufacturer. We used different temperatures from 750°C to 850°C to synthesize LiNi_0.8Co_0.15Mn_0.05O₂ and compare all of them and we can find which is the best synthesis conditions for it finally. XRD were used to analyse the phases of LiNi_0.8Co_0.15Mn_0.05O₂ and SEM could help us to see morphologies. Electrochemical properties showed that the LiNi_0.8Co_0.15Mn_0.05O₂ synthesized at 800°C delivered the highest discharge capacity and best cycling performance. DSC test would show us that the LiNi_0.8Co_0.15Mn_0.05O₂ exhibited good thermal stability because of the existence of Manganese.
GP-21 Cutting Performance Through Cutting Temperature Measurement of (Ti, Al, Si)N Coated Tool for High-Speed Ball-End Milling M.C. Kang, J.S. Kim, K.H. Kim, S.H. Shin (Pusan National University, Korea) The demands for cutting tools tend to still longer service life and higher speed in cutting process. To satisfy these demands, hard and wear resistant thin coatings have to be deposited on cutting tools. The functionality of the coating must be ensured at the high temperature reached at the cutting edge during machining. At these temperatures, oxidation of the coatings may lead to problems. To further enhance the oxidation resistance, the (Ti, Al)N and (Ti, Al, Si)N films are compared. The investigated coatings were deposited by reactive DC magnetron sputtering on WC-Co substrate. XRD, GDOES, XPS and scratch test data were provided. In order to evaluate cutting performance, the both films were applied to ball-endmill cutting tool made of WC-Co material. High-speed ball-end milling tests, conducted with both previously mentioned coatings, demonstrated the enhanced cutting performance of the super-hard coatings, especially at elevated cutting temperatures. A K-type thermocouple, implanted in a hole in the work-piece for cutting temperature measurement, was introduced in this work. Nano composite, Oxidation resistance, cutting temperature, (TiAlSi)N coated tool, high-speed ball-end milling.
GP-22 Hydrogen Plasma Immersion Ion Implantation of AZ91 Magnesium Alloy for Biomedical Applications Y. Xin (Tsinghua University, China); C.L. Liu (City University of Hong Kong); M. Xu (Shanghai Jiao Tong University and City University of Hong Kong); P.K. Chu (City University of Hong Kong); G. Tang (Tsinghua University, China) Magnesium and its alloy are potential materials in biodegradable implants. However, the rapid degradation rates of magnesium and magnesium-based alloys in the electrolytic physiological environment may not provide sufficient time for bone tissues to heal. In this work, hydrogen plasma immersion ion implantation is conducted on AZ91 magnesium alloy to improve the corrosion resistance. The corrosion behavior in simulated body fluid (SBF) solution is studied. Our results disclose that the implantation voltage plays a crucial role in the corrosion resistance of treated samples. Potentiodynamic polarization results shows that the corrosion resistance of the sample plasma implanted at 30 kV is enhanced significantly, whereas no improvement is observed from the sample implanted at 20 kV. In the simulated body fluid immersion test, no filiform corrosion is detected on both the untreated and hydrogen implanted samples, but magnesium phosphate and calcium phosphate are observed on the surfaces of both the untreated and treated samples soaked in SBF for 48 h.
GP-23 Alternative Route for the Formation of Organic Thin Films : Inkjet Printing Process and Its Properties M. Chen, H.S. Koo (Ming-Hsin University, Taiwan) A promising alternative approach for fabricating organic polymeric thin films have been significantly investigated in the processing of inkjet printing technology. The as-printed precursor inks were synthesized by chemical route and its physical characteristics is compatible to the performance of the modified inkjet printing-heads. The chemical ingredients of UV curable polymeric inks include nanoparticle colorant pigments, surfactant, and self-synthesized dispersants. The results exhibit superior characteristics of as-printed thin films in optical transmittance, surface morphology, and chromaticity. Here, the performance of inkjet printing system, the characteristics of as-printed precursor inks and its films were demonstrated. This technique have also been applied to the manufacturing of flexible electronics, RFID, large-area sensor for artificial skins, color filters, OLED, and metallic contact electrodes.

Time Period ThP Sessions | Topic G Sessions | Time Periods | Topics | ICMCTF2007 Schedule