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Paul K Chu - One of the best experts on this subject based on the ideXlab platform.
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effects of chromium Ion implantatIon voltage on the corrosIon resistance and cytocompatibility of dual chromium and oxygen plasma Ion implanted biodegradable magnesium
Surface & Coatings Technology, 2013Co-Authors: Xiongbo Yang, Jiang Jiang, Paul K ChuAbstract:Abstract Magnesium is modified by chromium Ion implantatIon at different voltages followed by oxygen Ion implantatIon to improve the corrosIon resistance and cytocompatibility. All the implanted samples exhibit improved corrosIon resistance and the ones implanted at a lower voltage yield better results. The chromium-rich layer with chromium in the metallic state beneath the protective oxide film may undermine the electrochemical stability by inducing galvanic effects which lead to poorer corrosIon resistance. Although dual Cr–O plasma immersIon Ion implantatIon promotes osteoblast adhesIon and proliferatIon on the magnesium samples and produces a more favorable environment for osteoblast growth, optimal results require careful selectIon of the Ion implantatIon voltage.
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Hollow Cathode Glow Discharge for Plasma Ion ImplantatIon
IEEE Conference Record - Abstracts. 2005 IEEE International Conference on Plasma Science, 2005Co-Authors: S. Q.yang, H. F. Jiang, J. T. Cui, X. B. Tian, Ricky K. Y. Fu, Paul K ChuAbstract:Summary form only given. Hollow cathode glow discharge has been investigated and utilized in plasma Ion implantatIon. In this mode, local plasma Ion implantatIon can be performed. The hollow cathode glow discharge is sustained by a radio-frequency source and the discharge behavior is investigated in this work. Argon and nitrogen are utilized in the experiments. The inner diameter of the hollow cathode changes from 1 mm to 6 mm. The excitatIon power of the radio-frequency source varies from 100 W to 400 W and gas flow changes from 5 sccm to 40 sccm. The collector to obtain Ion density is negatively biased to -100 V to -400 V in front of the hollow cathode. The experimental results demonstrate that the plasma density is much dependent on the inner diameter of the hollow cathode, excitatIon power, gas flow, etc. The collected Ion current increases monotonically with the RF power and inner diameter of the cathode but not with the gas flow as observed in our work
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recent developments and applicatIons of plasma immersIon Ion implantatIon
Journal of Vacuum Science & Technology B, 2004Co-Authors: Paul K ChuAbstract:Plasma immersIon Ion implantatIon (PIII) is an established technique in some niche microelectronics applicatIons, such as synthesis of silicon on insulator. In other applicatIons, such as shallow junctIon formatIon by plasma doping, trench doping, and others, PIII possesses unique advantages over conventIonal techniques. In the last few years, there have been significant breakthroughs in these areas. Recent developments in plasma doping, direct-current plasma immersIon Ion implantatIon that excels in planar sample processing, PIII of insulating materials, as well as plasma surface modificatIon of biomaterials are reviewed in this article.
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modeling of incident particle energy distributIon in plasma immersIon Ion implantatIon
Journal of Applied Physics, 2000Co-Authors: Xiubo Tian, Dixon T K Kwok, Paul K ChuAbstract:Plasma immersIon Ion implantatIon is an effective surface modificatIon technique. Unlike conventIonal beam-line Ion implantatIon, it features Ion acceleratIon/implantatIon through a plasma sheath in a pulsed mode and non-line-of-sight operatIon. Consequently, the shape of the sample voltage pulse, especially the finite rise time due to capacitance effects of the hardware, has a large influence on the energy spectra of the incident Ions. In this article, we present a simple and effective analytical model to predict and calculate the energy distributIon of the incident Ions. The validity of the model is corroborated experimentally. Our results indicate that the Ion energy distributIon is determined by the ratio of the total pulse duratIon to the sample voltage rise time but independent of the plasma compositIon, Ion species, and implantatIon voltage, subsequently leading to the simple analytical expressIons. The Ion energy spectrum has basically two superimposed components, a high-energy one for the majorit...
J R Conrad - One of the best experts on this subject based on the ideXlab platform.
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chromium plating pollutIon source reductIon by plasma source Ion implantatIon
Surface & Coatings Technology, 1996Co-Authors: A Che, X Qiu, Kuma Sridhara, W G Horne, R A Dodd, A H Hamdi, Alaa Abdel-azim Elmoursi, G W Malaczynski, J R ConradAbstract:There is growing concern over the environmental and workers' health issues due to the chemical baths and rinse water used in the hard chromium plating process. In this regard the significant hardening response of chromium to nitrogen Ion implantatIon can be environmentally beneficial from the standpoint of decreasing the thickness and the frequency of applicatIon of chromium plating. In this paper the results of a study of nitrogen Ion implantatIon of chrome-plated test flats using the non-line-of-sight plasma source Ion implantatIon (PSII) process are discussed. Auger electron spectroscopy (AES) showed the implanted layer thickness to be about 2000 A. Electron spectroscopy for chemical analysis (ESCA) indicated the formatIon of chromium nitride phase in the implanted layer. The wear resistance improves after implantatIon owing to both surface hardening and a decrease in coefficient of frictIon. CorrosIon resistance in saline solutIon improved moderately after PSII treatment.
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chromium plating pollutIon source reductIon by plasma source Ion implantatIon
International Conference on Plasma Science, 1995Co-Authors: A Che, X Qiu, Kuma Sridhara, W G Horne, R A Dodd, A H Hamdi, Alaa Abdel-azim Elmoursi, G W Malaczynski, J R ConradAbstract:There is growing concern over the environmental toxicity and workers' health issues due to the chemical baths and rinse water used in the hard chromium plating process. In this regard the significant hardening response of chromium to nitrogen Ion implantatIon can be environmentally beneficial from the standpoint of decreasing the thickness and the frequency of applicatIon of chromium plating. In this paper the results of a study of nitrogen Ion implantatIon of chrome plated test flats using the non-line-of-sight Plasma Source Ion ImplantatIon (PSII) process, are discussed. Surface characterizatIon was performed using Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES), and Electron Spectroscopy for Chemical Analysis (ESCA). The surface properties were evaluated using a microhardness tester, a pin-on-disk wear tester, and a corrosIon measurement system. Industrial field testing of nitrogen PSII treated chromium plated parts showed an improvement by a factor of two compared to the unimplanted case.
Jiang Jiang - One of the best experts on this subject based on the ideXlab platform.
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effects of chromium Ion implantatIon voltage on the corrosIon resistance and cytocompatibility of dual chromium and oxygen plasma Ion implanted biodegradable magnesium
Surface & Coatings Technology, 2013Co-Authors: Xiongbo Yang, Jiang Jiang, Paul K ChuAbstract:Abstract Magnesium is modified by chromium Ion implantatIon at different voltages followed by oxygen Ion implantatIon to improve the corrosIon resistance and cytocompatibility. All the implanted samples exhibit improved corrosIon resistance and the ones implanted at a lower voltage yield better results. The chromium-rich layer with chromium in the metallic state beneath the protective oxide film may undermine the electrochemical stability by inducing galvanic effects which lead to poorer corrosIon resistance. Although dual Cr–O plasma immersIon Ion implantatIon promotes osteoblast adhesIon and proliferatIon on the magnesium samples and produces a more favorable environment for osteoblast growth, optimal results require careful selectIon of the Ion implantatIon voltage.
Xiuheng Wang - One of the best experts on this subject based on the ideXlab platform.
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radio frequency plasma nitriding and nitrogen plasma immersIon Ion implantatIon of ti 6a1 4v alloy
Surface & Coatings Technology, 1997Co-Authors: Sai Wang, B Y Tang, Xuchu Zeng, Yanbin Chen, Xiuheng WangAbstract:Abstract Nitrogen Ion implantatIon improves the wear resistance of Ti-6A1-4V alloys by forming a hard TiN superficial passivatIon layer. However, the thickness of the layer formed by traditIonal Ion implantatIon is typically 100–200 nm and may not be adequate for many industrial applicatIons. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersIon Ion implantatIon (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6A1-4V samples, RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The performance of our newly developed inductively coupled RF plasma source which is responsible for the success of the experiments is also described.
Xiongbo Yang - One of the best experts on this subject based on the ideXlab platform.
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effects of chromium Ion implantatIon voltage on the corrosIon resistance and cytocompatibility of dual chromium and oxygen plasma Ion implanted biodegradable magnesium
Surface & Coatings Technology, 2013Co-Authors: Xiongbo Yang, Jiang Jiang, Paul K ChuAbstract:Abstract Magnesium is modified by chromium Ion implantatIon at different voltages followed by oxygen Ion implantatIon to improve the corrosIon resistance and cytocompatibility. All the implanted samples exhibit improved corrosIon resistance and the ones implanted at a lower voltage yield better results. The chromium-rich layer with chromium in the metallic state beneath the protective oxide film may undermine the electrochemical stability by inducing galvanic effects which lead to poorer corrosIon resistance. Although dual Cr–O plasma immersIon Ion implantatIon promotes osteoblast adhesIon and proliferatIon on the magnesium samples and produces a more favorable environment for osteoblast growth, optimal results require careful selectIon of the Ion implantatIon voltage.
