Modern discharge plasma generators generate short pulses of plasma of high power (in megawatt range) and microsecond duration. Neither classical bolometers nor methods based on detection of electric current flow are applicable to power... more
Modern discharge plasma generators generate short pulses of plasma of high power (in megawatt range) and microsecond duration. Neither classical bolometers nor methods based on detection of electric current flow are applicable to power measurements in such machines. In our previous report [Z. Werner, J. Langner, J. Stanislawski, and J. Bialoskórski, J. Tech. Phys. 41, 55 (2000)] we presented several concepts, including differential thermocouple sensors. In this work we present the results of numerical simulations of the operation of such thermocouples, which help to find the limits within which the idea is useful and to optimize the detector design. Results of preliminary experiments are also presented.
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ABSTRACT To elucidate the interaction between defects and transition metal impurities in creating magnetic properties in wide band-gap semiconductors, single crystals of ZnO were irradiated with high-energy electrons, protons and Co ions.... more
ABSTRACT To elucidate the interaction between defects and transition metal impurities in creating magnetic properties in wide band-gap semiconductors, single crystals of ZnO were irradiated with high-energy electrons, protons and Co ions. Magnetization of samples was measured before and after room temperature irradiation. The measurements reveal that only Co implantation creates measurable magnetization, which is related to the simultaneous introduction of defects. Consequences of the experimental results are discussed.
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ABSTRACT Ion implantation was utilized as a pre-treatment method for direct bonding of ceramics with copper. Aluminum nitride samples were implanted with metallic ions (Ti, Cr, Fe, Cu) and/or with oxygen. The choice of implanted species... more
ABSTRACT Ion implantation was utilized as a pre-treatment method for direct bonding of ceramics with copper. Aluminum nitride samples were implanted with metallic ions (Ti, Cr, Fe, Cu) and/or with oxygen. The choice of implanted species was based upon thermodynamic considerations. Direct bonding was performed by a conventional method of furnace annealing in nitrogen atmosphere. Shear strength measurements of the joints were used as a method of joint quality verification. The samples were additionally characterized by RBS measurements and the shear fracture surface was analyzed by optical microscopy.It has been concluded that the joints formed on ion implantation pre-treated aluminum nitride exhibit superior quality with respect to conventionally treated (oxidized) material. It has also been found that the optimum properties are exhibited by material in which thin titanium nitride surface layer is formed by low-fluence Ti implantation and that the presence of oxygen has a detrimental effect upon the joint quality, although oxygen implantation is potentially a promising approach.
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ABSTRACT Silicon samples were implanted with up to 6E+16 cm−2 of 190 keV manganese and next treated with plasma pulses of duration about 1 μs and energy density up to 4 J cm−2. Channelled RBS spectra measured after pulse treatment reveal... more
ABSTRACT Silicon samples were implanted with up to 6E+16 cm−2 of 190 keV manganese and next treated with plasma pulses of duration about 1 μs and energy density up to 4 J cm−2. Channelled RBS spectra measured after pulse treatment reveal nearly perfect recovery of crystalline order with manganese segregated towards the surface and occupying non-substitutional positions. SQUID magnetization measurements show the formation of paramagnetic phase of concentration increasing with the applied manganese fluence.
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ABSTRACT B ions into Mg and Mg ions into B substrates were implanted in triple mode, i.e. each sample was sequentially implanted at three different energies starting from the highest one (80–150 keV range) to the lowest one (40–70 keV... more
ABSTRACT B ions into Mg and Mg ions into B substrates were implanted in triple mode, i.e. each sample was sequentially implanted at three different energies starting from the highest one (80–150 keV range) to the lowest one (40–70 keV range). The energies and fluencies in each particular batch were simulated to yield a possibly large region in which the Mg:B ratio corresponds to stoichiometric MgB2 compound. These structures were next annealed using high intensity hydrogen plasma pulses of energy densities between 1.5 and 4.0 J/cm2, or furnace annealed at 350–600 °C in a stream of flowing Ar-4%H2 mixture. The simulated profiles were in fair agreement with those derived from the RBS measurements. Magnetically modulated microwave absorption (MMMA), magnetization and resistance measurements showed that the superconducting transition onset temperature Tconset shifted from about 13 K in the best magnesium sample implanted with single-energy B ions, to 22–28 K for multi-energy implantation treatments. Respective shift in Mg-implanted boron samples was from about 33.3 K to 36.5 K. However, broadening of the transition to the superconducting state is observed for the multi-energy treatment in both cases. Possible reasons for these effects and proposed means to improve the method are discussed.
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Joining of carbon type ceramics with other materials presents an important challenge, especially in view of ITER technology. The crucial problem in joining is wettability of such ceramics with copper. In our previous works we succeeded in... more
Joining of carbon type ceramics with other materials presents an important challenge, especially in view of ITER technology. The crucial problem in joining is wettability of such ceramics with copper. In our previous works we succeeded in improving wettability using two-steps procedure, i.e.: pre-treatment of the ceramics surface with Ti ions implantation and/or deposition of metallic Ti using high intensity
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A new method for the formation of thin metallic coatings on steel substrates is demonstrated. The method is based on the use of high intensity plasma pulses. Depending on the choice of operational conditions of the plasma pulse generator,... more
A new method for the formation of thin metallic coatings on steel substrates is demonstrated. The method is based on the use of high intensity plasma pulses. Depending on the choice of operational conditions of the plasma pulse generator, it is possible to form pulses containing either both nitrogen and metal plasma or pure metallic plasma. In the present experiments plasma pulses of Ti, Co and W, are used. The feasibility of a two-step process is shown. In the first step there is a mixing of deposit-substrate components induced by melting and mutual diffusion. In the second one, there is a deposition of the metal coating of practically unlimited thickness on the intermediate mixed layer.
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Palladium-alloyed surface layers in titanium were formed by deposition of palladium followed by treatment with high-intensity nitrogen plasma pulses (pulsed implantation doping, PID), capable of melting the substrate, and compared with... more
Palladium-alloyed surface layers in titanium were formed by deposition of palladium followed by treatment with high-intensity nitrogen plasma pulses (pulsed implantation doping, PID), capable of melting the substrate, and compared with those formed by the ...
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This paper presents preliminary results of a new approach to forming a refractory metal (Mo) layer on Si, using intense pulses of Mo-N plasma. The new approach overcomes an inherent difficulty of mixing two materials with dissimilar... more
This paper presents preliminary results of a new approach to forming a refractory metal (Mo) layer on Si, using intense pulses of Mo-N plasma. The new approach overcomes an inherent difficulty of mixing two materials with dissimilar surface tensions in the liquid state when using proton beam pulses for melting the predeposited surface layer of a refractory metal. Previous attempts to mix a refractory metal with Si using the latter pulses were unsuccessful owing to a tendency of the pulse-melted refractory metal layer to collect into droplets and splash off. Since in the new approach the plasma-borne Mo atoms “sink” in the molten Si layer, there is no opportunity for them to form a separate Mo layer and an effective mixing between Mo and Si takes place. This mixing is demonstrated by the Mo in Si profiles obtained by Auger electron spectroscopy.
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The paper describes various types of modifications of the surface properties of solids under the influence of short-duration (10−6s), high-power (several megawatts) pulses of dense (1013–1017ionscm−2) plasma with various elemental... more
The paper describes various types of modifications of the surface properties of solids under the influence of short-duration (10−6s), high-power (several megawatts) pulses of dense (1013–1017ionscm−2) plasma with various elemental compositions, generated by rod-plasma injector-type machines developed at SINS. Depending on the operational conditions, a wide range of elemental compositions in the plasma pulses can be obtained from an almost pure metallic plasma of the discharge electrode material through mixed gaseous–metallic plasmas to a pure plasma of the working gas. Such pulses, apart from depositing plasma material on the substrate surface carry sufficient energy to melt the surface layer. This leads to a number of interesting effects like diffusion in the molten phase, fast epitaxial re-crystallization, rapid re-solidification accompanied by the formation of new phases, mixing (alloying) of the surface layer with the bulk material and others. The peculiar features of pulsed plasma beam interactions with the substrate are discussed for a number of cases, in particular:•formation of photovoltaic p+–n and n+–p junctions and ohmic contacts in Si under the influence of BF3 and PF5 plasma pulses;•nitriding of steels and martensite–austenite transitions under the influence of N plasma pulses;•coating of steel with intermixed (alloyed) layers of Cu using N plasma pulses with controlled content of the appropriate metal; and•transition from deposition to ablation for Cu–N plasma pulses for varying proportions of constituents.The results presented in the paper indicate that intense pulse plasma beams may be an extremely valuable tool in the modification of the surface properties of materials of technological importance.
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The stainless steel substrates AISI321 were irradiated with high intensity pulsed plasma beams containing copper and nitrogen ions at various proportions. The mass change, the total copper content and elemental composition of the surface... more
The stainless steel substrates AISI321 were irradiated with high intensity pulsed plasma beams containing copper and nitrogen ions at various proportions. The mass change, the total copper content and elemental composition of the surface layer were examined. An effective mixing of Cu and N atoms with the substrate material accompanied by mass ablation has been revealed for N rich plasma
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Intense pulses of nitrogen plasma melt the near-surface layer of the substrate and simultaneously dope it with nitrogen. For the number of pulses from 1 to 20 the dose of retained nitrogen in iron and steels ranges from 0.2 to 6 × 1017... more
Intense pulses of nitrogen plasma melt the near-surface layer of the substrate and simultaneously dope it with nitrogen. For the number of pulses from 1 to 20 the dose of retained nitrogen in iron and steels ranges from 0.2 to 6 × 1017 N/cm2, as determined by Nuclear Reaction Analysis (NRA). In 1H18N9T stainless steel investigated in the present work,
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The effect of Cl− ions (0–1M NaCl) on the anodic behaviour of two series of sputter-deposited Al–Ta (11–46at.%) and Al–Nb (13–46at.%) amorphous alloys was investigated in a neutral electrolyte by using electrochemical methods and the... more
The effect of Cl− ions (0–1M NaCl) on the anodic behaviour of two series of sputter-deposited Al–Ta (11–46at.%) and Al–Nb (13–46at.%) amorphous alloys was investigated in a neutral electrolyte by using electrochemical methods and the results were compared with those for Al–Mo and Al–W alloys. In solutions containing Cl− the alloys broke down at and above the pit nucleation potential
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ABSTRACT Anodic layers grown on Al-Ta sputter deposited amorphous alloys were studied by electrochemical methods, AES, and RBS. The alloy composition ranged from Al(9)0Ta(10) to Al(70)Ta(30). It has been found that an increase of... more
ABSTRACT Anodic layers grown on Al-Ta sputter deposited amorphous alloys were studied by electrochemical methods, AES, and RBS. The alloy composition ranged from Al(9)0Ta(10) to Al(70)Ta(30). It has been found that an increase of breakdown potential E,P, caused by refractory metal content extends over a wide concentration range from 0.01 M up to 1 M NaCl. AES measurements have shown that Ta remains in an oxidized state over the whole thickness of the anodic layer thus confirming the model of Ta acting as a passivity promoter rather than a dissolution moderator. RBS results clearly demonstrate that in low Ta content layers a thin alumina film is formed on the top surface of the anodic layer. For higher Ta content only a depletion in Ta is observed on the surface. The latter result differs front those obtained previously by other authors and may be caused by differences in experimental conditions and/or the alloy structure. The role of refractory metals in the passivity of Al-based amorphous alloys is discussed.
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... The pitting potential can be further enhanced by associated additions of silicon, for example, by about 500600 mV with an addition of6at.Si. ... 2. AlSaffar, AH, Ashworth, V., Bairamow. AKO, Chives, DJ. Grant, WA and Procter, RPM... more
... The pitting potential can be further enhanced by associated additions of silicon, for example, by about 500600 mV with an addition of6at.Si. ... 2. AlSaffar, AH, Ashworth, V., Bairamow. AKO, Chives, DJ. Grant, WA and Procter, RPM Corros. ... John Wiley and Sons Ltd. 1985. 15. ...
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Modelling of the similar depth profiles of two different kinds of ions, implanted to WC-Co tools, used in wood-based material machining. An attempt was made to model the similar depth profiles of ions of two commonly used gases, i.e.,... more
Modelling of the similar depth profiles of two different kinds of ions, implanted to WC-Co tools, used in wood-based material machining. An attempt was made to model the similar depth profiles of ions of two commonly used gases, i.e., nitrogen and argon, for the parameter values possible to obtain using classical implanters. Modelling was executed in two stages. Similar profiles were obtained for the acceleration voltage value of 35 kV in the case of nitrogen and the sum of the acceleration voltages of 65+32.5 kV in the case of argon. The difference in the obtained profile parameter values, such as: the peak volume dopant concentration of the implanted element, the projected range and the range straggling, was less than 1%.
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This study explored the effects of nitrogen (N) ion implantation of drills for wood-based materials. Modification of a tool’s surface is a common process of prolonging its lifetime. For the purpose of this study, ion implantation was used... more
This study explored the effects of nitrogen (N) ion implantation of drills for wood-based materials. Modification of a tool’s surface is a common process of prolonging its lifetime. For the purpose of this study, ion implantation was used for modification of drills commonly used in the furniture industry. The rake face of high-speed steel drills was implanted with different doses of nitrogen ions. Durability tests were conducted with the use of a computerized numerical control woodworking machine used for drilling laminated particleboards. The cutting force and drilling torque were measured. The obtained results were presented as wear curves of the examined drill bits. Based on the results, tools implanted with nitrogen ions at different doses had a longer tool life
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We present the preliminary results of the investigations on the detection of high power plasma pulses. Three types of detectors were examined: pyroelectric sensor, plasma-to-IR radiation converter, and thin film differential thermocouple... more
We present the preliminary results of the investigations on the detection of high power plasma pulses. Three types of detectors were examined: pyroelectric sensor, plasma-to-IR radiation converter, and thin film differential thermocouple sensor. The operation of the detectors was studied for microsecond range of the plasma pulse duration. Numerical simulation of the thermal evolution of multi-layer structures was used to optimise the design of the detectors. It is concluded that thermocouple sensors are able to provide the most reliable data. Directions of further development of this kind of sensors are discussed
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ABSTRACT Ion implantation effects on resistance of alloys and ceramic coatings to the high-temperature corrosion have been reviewed. The most significant results on implantation of reactive elements (Y, La, Ce and other rare earth... more
ABSTRACT Ion implantation effects on resistance of alloys and ceramic coatings to the high-temperature corrosion have been reviewed. The most significant results on implantation of reactive elements (Y, La, Ce and other rare earth elements) into alloys and aluminum, boron, silicon, tantalum, and titanium into ceramic coatings have been cited. Ion implantation affects not only the oxide growth rate, but also seems to modify the growth mechanism and the oxide structure.
Research Interests: Materials Science, Metallurgy, Silicon, Corrosion, Boron, and 5 moreCeramic, Ion Implantation, Aluminium, Oxide, and Tantalum
Influence of the ion implantation of nitrogen and selected metals on the lifetime of WC-Co indexable knives during MDF machining. The paper presents the results of durability tests for WC-Co indexable knives during the machining of MDF.... more
Influence of the ion implantation of nitrogen and selected metals on the lifetime of WC-Co indexable knives during MDF machining. The paper presents the results of durability tests for WC-Co indexable knives during the machining of MDF. The knives were implanted with nitrogen, zirconium, molybdenum and tin, using MEVVA type implanter with non-mass separated beam. Additionally, the Monte Carlo simulation results of the main parameters of the depth profiles of the implanted elements are presented in this paper. A higher correlation of tool life with the project range and range straggling than with the parameter of the peak volume dopant concentration was demonstrated.
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Abstract The range-energy relations for protons of energy between 0.8 MeV and 2.0 MeV in Si and Ge were determined. For the measurement of the proton energy a 100 channel pulse-height analyzer and silicon semiconductor detector were used.... more
Abstract The range-energy relations for protons of energy between 0.8 MeV and 2.0 MeV in Si and Ge were determined. For the measurement of the proton energy a 100 channel pulse-height analyzer and silicon semiconductor detector were used. The range energy relations for Si and Ge were assumed to be of the form R ( ω m) = aE χ (MeV) and the parameters a and x were calculated using a least-squares fit. The following analytical expressions in the measured energy range were obtained: R Si ( ω m) = 16.41 E 1.64 (MeV) and R Ge ( μ m) = 7.52 E 2.05 (MeV).
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In the presented work we examined two methods of friction reduction of alumina samples; (i) formation of thin surface layer of reduced hardness (to take advantage of Tabor and Bowden concept of adhesive friction in layered materials) and... more
In the presented work we examined two methods of friction reduction of alumina samples; (i) formation of thin surface layer of reduced hardness (to take advantage of Tabor and Bowden concept of adhesive friction in layered materials) and (ii) introduction of nanometer-sized precipitates of solid lubricants to the surface layer of material. The samples were implanted with various doses of inert ions (Ar) or with soft metal ions (In). Both methods lead to significant friction reduction, the best results being obtained for alumina implanted with In ions when the friction coefficient was reduced more than three times. The measurements of nanohardness revealed substantially lower hardness of the irradiated layers. The sample surface was inspected by Scanning Electron Microscopy (SEM) technique supplemented with the elemental analysis. The results obtained are discussed taking into account the level of radiation damage caused by ion implantation and the presence of impurity atoms. The analysis of the experimental data allowed us to explain the obtained results within the frames of the adhesive friction theory.
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Wetting properties of ceramic materials may be enhanced by treating them with high-intensity plasma pulses carrying a substantial fraction of metallic ions. Rod Plasma Injectors (RPI), developed originally for fusion studies, may generate... more
Wetting properties of ceramic materials may be enhanced by treating them with high-intensity plasma pulses carrying a substantial fraction of metallic ions. Rod Plasma Injectors (RPI), developed originally for fusion studies, may generate such plasma pulses containing the working gas used for discharge initiation and the metal ions eroded from the discharge electrodes. We examined the plasma pulse technology and
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Intense pulsed ion and/or plasma beams can modify the surface properties of materials by melting their near surface region and doping and/or coating with foreign atoms reaching doses in the order of 1017 cm−2 in a single pulse. Such... more
Intense pulsed ion and/or plasma beams can modify the surface properties of materials by melting their near surface region and doping and/or coating with foreign atoms reaching doses in the order of 1017 cm−2 in a single pulse. Such processes can be performed using a Rod Plasma Injector (RPI), where plasma pulses are generated as a result of a low-pressure,
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Cathodoluminescence and reflectivity spectra are studied in homogeneous CdSxSe1−x mixed crystals with x = 0.85, 0.64, 0.47, 0.29 over the temperature range 7 to 110 K. It is found that the luminescence at 7 K is dominated by bound exciton... more
Cathodoluminescence and reflectivity spectra are studied in homogeneous CdSxSe1−x mixed crystals with x = 0.85, 0.64, 0.47, 0.29 over the temperature range 7 to 110 K. It is found that the luminescence at 7 K is dominated by bound exciton emission. The binding energies of exciton complexes are deduced from the spectra and found to decrease linearly with the increase of selenium content in the crystals. It is concluded that excitons in different CdSxSe1−x mixed crystals are bound to the same impurity or defect. Les spectres de cathokoluminescence et de reflectivite des cristaux melanges CdSxSe1−x pour x = 0,85; 0,64;0,47; 0,29 sont ete etudie dans la gamme 7 a 110 K de la temperature. On a trouve que les excitons lies jouent un role dominant dans les spectres de luminescence a 7 K. En tenant compte de les spectres on a dedui l'energie de liaison avec la croissance de contenu de selenium dans le cristal. On a conclu que les excitons pour les differentes cristaux melanges CdSxSe1−x sont lie avec meme defauts.
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ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select... more
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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Annealing of Hall-mobility changes in n-type germanium irradiated with 1 MeV electrons at 85°K was investigated using an isochronal technique. Two annealing stages which have been reported earlier were confirmed and separated. One stage... more
Annealing of Hall-mobility changes in n-type germanium irradiated with 1 MeV electrons at 85°K was investigated using an isochronal technique. Two annealing stages which have been reported earlier were confirmed and separated. One stage at above 100°K is connected with ``contact'' annealing, and a second one close to 140°K is caused by bulk annealing. The latter stage corresponds to the stage found already by J. C. Pigg for gamma irradiation.