Focus Shots Research Articles

Hard TiCx/SiC/a-C:H nanocomposite thin films using pulsed high energy density plasma focus device

Thin films of TiCx/SiC/a-C:H were synthesized on Si substrates using a complex mix of high energy density plasmas and instability accelerated energetic ions of filling gas species, emanated from hot and dense pinched plasma column, in dense plasma focus device. The conventional hollow copper anode of Mather type plasma focus device was replaced by solid titanium anode for synthesis of TiCx/SiC/a-C:H nanocomposite thin films using CH4:Ar admixture of (1:9, 3:7 and 5:5) for fixed 20 focus shots as well as with different number of focus shots with fixed CH4:Ar admixture ratio 3:7. XRD results showed the formation of crystalline TiCx/SiC phases for thin film synthesized using different number of focus shots with CH4:Ar admixture ratio fixed at 3:7. SEM results showed that the synthesized thin films consist of nanoparticle agglomerates and the size of agglomerates depended on the CH4:Ar admixture ratio as well as on the number of focus shots. Raman analysis showed the formation of polycrystalline/amorphous Si, SiC and a-C for different CH4:Ar ratio as well as for different number of focus shots. The XPS analysis confirmed the formation of TiCx/SiC/a-C:H composite thin film. Nanoindentation results showed that the hardness and elastic modulus values of composite thin films increased with increasing number of focus shots. Maximum values of hardness and elastic modulus at the surface of the composite thin film were found to be about 22 and 305GPa, respectively for 30 focus shots confirming the successful synthesis of hard composite TiCx/SiC/a-C:H coatings.

The effect of TiN nanoparticles deposition with different number of shots on SS316L by plasma focus device

In this paper, we present the result of TiN nanocrystalline deposition on SS316L, using a 4 kJ plasma focus (PF) device for 10, 20, and 30 focus shots. The effect of different number of focus shots on micro-structural changes of thin film is characterized by field emission scanning electron microscope. Existence of grains in different size confirms the formation of TiN nanocrystals on the surface of SS316L substrate. X-ray diffraction (XRD) reveals the formation of a nanocrystalline titanium nitride coating on the surface of SS316L samples. The crystalline size of TiN obtained from XRD data is strongly dependent on the number of focus shots. Thickness of the elements found on the surface of the treated sample that obtain by Rutherford backscattering spectroscopy (RBS) analysis is in the range of 150×1015−200×1015 atoms/cm2. All the existence elements in the coated samples are identified by Particle Induced X-ray Emission (PIXE) spectra. Investigation on the corrosion resistance of TiN coatings was performed using an electrochemical potentiodynamic polarization. Our results suggest that TiN nanocrystalline implantation with proper ion fluences using PF can significantly improve the corrosion resistance of SS316L.

Investigation of structural properties of chromium thin films prepared by a plasma focus device

We report the synthesis of chromium thin films on Si(400) substrates by utilizing a low-energy (1.6 kJ) plasma focus device. The films of chromium are deposited with different numbers of focus shots (15, 25 and 35) at a distance of 8 cm and at 0° angular position with respect to the anode axis. The films are investigated structurally by x-ray diffraction analysis and morphologically by atomic force microscopy and scanning electron microscopy. The elemental composition is characterized by energy dispersive x-ray analysis. Furthermore, Vicker's micro hardness is used to study the mechanical properties of the deposited films. The degree of crystallinity of chromium films, the size of the particles and the hardness values of the films increase when the number of focus shots is raised from 15 to 25 and then decrease when the substrate is treated with 35 shots. We discuss the dynamic processes involved in the formation of the chromium films.

Filmic Space and Real Time in Hitchcock’s Rope

FILMIC SPACE AND REAL TIME IN HITCHCOCK'S ROPE "Brandon, how did you feel?""When?""During it?"Philip Morgan to Brandon Shaw IntroductionRope explores some of the fundamental characteristics of the cinematic abstraction of time and space by using the mobile camera as an agent that gives plastic reality to subjective material. In Rope, a synthesis of real time and filmic space forces the viewer to absorb narrative information on multiple, often distastefully ironic levels. At the same time, the viewer is given freedom of selection in terms of how, when, and why his/her attention is split, inviting some comparison with similar choices experienced during depth of focus shots, a spatial configuration that Hitchcock characteristically avoided. The movement of the camera throughout the film places the viewer in the ethically, emotionally, and psychologically uncomfortable position of perceiving perversity in the relationship between image and dialogue. For example, during the...

TiAlN coatings synthesised using a dense plasma focus system and varied focus shots

TiAlN coatings were synthesised by a 2.3 kJ pulsed plasma focus system. The effect of focus shots on crystallography, microstructure, surface morphology, roughness and hardness was investigated. The coating's crystallography and microstructure were investigated using X-ray diffraction (XRD) characterisation. The XRD data showed that TiAlN coatings were crystallised in the cubic NaCl B1 structure with orientations in the (111), (200), (220) and (311) crystallographic planes. Texture coefficients showed a competition between (111) and (200) planes. The coatings surface morphology and thickness analyses were carried out using scanning electron microscopy (SEM). SEM micrographs showed dense and uniformly spread film with fine-grained morphology with hardly any pit, hole and crater. The surface roughness and hardness of TiAlN coatings were investigated by atomic force microscopy and Vickers microhardness tester. Grain size and roughness were found to decrease, whereas thickness and hardness were found to increase, with increasing focus shots.

Deposition of Chromium Thin Films on Stainless Steel-304 Substrates Using a Low Energy Plasma Focus Device

In this paper, we study thin films of chromium deposited on stainless steel-304 substrates using a low energy (1.6 kJ) plasma focus device. The films of chromium are likewise deposited with 25 focus shots each at various axial distances from the top of the anode (3, 5, 7, 9 and 11 cm). We also consider different angular positions with respect to the anode axis (0°, 15° and 30°) at a distance of 5 cm from the anode tip to deposit the chromium films on the stainless steel substrates. To characterize the structural properties of the films, we benefit from X-ray diffraction (XRD) analysis. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) are applied as well to study the surface morphology of these deposited films. Furthermore, we make use of Vicker’s micro-hardness measurements to investigate the mechanical properties of chromium thin films. The XRD results show that the degree of crystallinity of chromium thin films depends on the substrate axial and angular positions. The AFM images illustrate that the film deposited at the distance of 5 cm and the angular position of 0° has quite a uniform surface with homogeneous distribution of grains on the film surface. From the hardness results, we observe that the sample deposited at the axial distance of 5 cm from the anode tip and at the angle of 0° with respect to the anode axis, is harder than the other deposited films.

Synthesis of nanostructured multiphase (Ti,Al)N/a-Si 3N 4 thin films using dense plasma focus device

A 2.3 kJ pulsed plasma focus device was used to prepare thin films of nc-(Ti,Al)N/a-Si 3N 4 at room temperature. The plasma focus device, fitted with copper anode encapsulated with Ti 0.5Al 0.5 anode, was operated with nitrogen as the filling gas. Films were deposited with various number of focus shots, at 90 mm from top of the anode and at zero angular position with respect to anode axis. XRD patterns show the growth of polycrystalline (Ti,Al)N thin films with orientations in the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) crystallographic planes. Behavior of lattice constant, grain size and film roughness of deposited film as a function of variation in number of focus shots is discussed. SEM micrographs of film deposited with 15 number of focus shots exhibit well-developed net like structure of nc-(Ti,Al)N/a-Si 3N 4 and possibly nc-(Ti,Al)N/a-Si 3N 4/a-AlN or nc-TiN/a-Si 3N 4/a-AlN. Surface Roughness ranging 64 nm to 89 nm was also observed.

Deposition of tungsten nitride on stainless steel substrates using plasma focus device

Tungsten nitride (WN) films were deposited on the stainless steel-304 substrate by a 2 kJ Mather-type plasma focus device. The preparation method and characterization data are presented. X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed for the characterization of the samples obtained with different number of focus shots, respectively. The average size of crystallites (from XRD), sub-micro-structures (from SEM) and particles (from AFM images) increase when the number of shots increase from 10 to 20 then 30, then they decrease when the substrate is exposed to 40 shots.

Structural and Morphological Investigations of Deposited Tungsten Nitride Thin Films Using Plasma Focus Device

Tungsten nitride thin films were deposited on the stainless steel-304 substrates by a 2 kJ Mather-type plasma focus device. The preparation method and characterization data are presented. The average size of crystallites, sub-micro structures and size of grains were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) respectively, which increases by increasing the number of focus shots from 10 to 20 then 30 shots.

Role of charge particles irradiation on the deposition of AlN films using plasma focus device

Highly crystalline AlN films are deposited on Si substrate by the bombardment of charge particles emanating from plasma focus device. Deposition of AlN films are carried out for multiple focus shots at room temperature. Numbers of ions (1.3×10 19–5.6×10 19 m −3) are emitted during one focus shot. X-rays diffraction results reveal that an amorphous and crystalline AlN films are obtained for 1 and 3 focus shots, respectively. Crystallinity of AlN film increases up to 5 focus shots while it starts to decrease for 15 and 20 focus shots. The average crystallite size of AlN (1 0 0) phase increases from 33 to 140 nm for 3–5 focus shots, whereas it starts to decrease from 26 to 22 nm for 15–20 focus shots. Raman's spectroscopy exhibits the presence of A 1 (TO) and E 1 (TO) modes at ∼ 611 and ∼ 665 cm −1 positions respectively confirming the formation of AlN film. Fourier's transform infrared spectroscopy indicates the presence of strong absorption peak at ∼ 667 cm −1 position. Field emission scanning electron microscopic investigation reveals that different surface morphologies for different focus shots are observed which are mesh like but uniform for 1 shot, dense microstructure (rounded grains) for 3 shots, rough surface (large particulates) for 5 shots, rounded grains but dense microstructure for 15 shots and multi-layers formation showing rounded grains for 20 shots. Thickness of AlN film deposited for 1 focus shot is uniform and is about 190 nm. Energy dispersive X-ray spectroscopic results show the presence of Al and N elements in AlN film deposited for 5 focus shots.

Deposition of zirconium carbonitride composite films using ion and electron beams emitted from plasma focus device

Abstract Nanocrystalline zirconium carbonitride (ZrCN) composite films were deposited on zirconium substrates for multiple (10, 20, 30, 40 and 50) focus shots. X-ray diffraction analysis shows diffraction peaks corresponding to nitrides (ZrN, Zr 2 N and Zr 3 N 4 ), carbide (ZrC) and carbonitride (Zr 2 CN), confirming the formation of ZrCN composite films. The average crystallite size estimated for ZrN (2 0 0) and Zr 2 CN (1 1 1) planes are found to vary from 10 to 20 nm. Maximum compressive stresses of ∼3.9 GPa in Zr 2 N (0 0 2) plane for 30 focus shots and maximum tensile stresses of ∼6.5 GPa in ZrN (2 0 0) plane for 20 focus shots are observed. Tensile stresses observed in Zr 2 CN (1 1 1) plane are transformed to compressive stresses for higher (40 and 50) focus shots. Raman analysis reveals the emergence of D and G bands related to carbide phases during the film deposition process. Scanning electron microscope analysis exhibits the nanocrystalline microstructure patterns of the composite films. Microstructure patterns showing agglomerates of 30–300 nm dimensions are also observed. Microhardness values of ZrCN composite films increases with increasing number of focus shots and is equal to 5.6 ± 0.45 GPa for 10 g imposed load, which is 4.5 times that of the virgin one.

Low energy repetitive miniature plasma focus device as high deposition rate facility for synthesis of DLC thin films

Diamond-like carbon (DLC) films were deposited on Si (1 0 0) substrate using a low energy (219 J) repetitive (1 Hz) miniature plasma focus device. DLC thin film samples were deposited using 10, 20, 50, 100 and 200 focus shots with hydrogen as filling gas at 0.25 mbar. The deposited samples were analyzed by XRD, Raman Spectroscopy, SEM and XPS. XRD results exhibited the diffraction peaks related to SiO 2, carbon and SiC. Raman studies verified the formation amorphous carbon with D and G peaks. Corresponding variation in the line width (FWHM) of the D and G positions along with change in intensity ratio ( I D/ I G) in DLC films was investigated as a function of number of deposition shots. XPS confirmed the formation sp 2 (graphite like) and sp 3 (diamond like) carbon. The cross-sectional SEM images establish the 220 W repetitive miniature plasma focus device as the high deposition rate facility for DLC with average deposition rate of about 250 nm/min.

Using Mather-type plasma focus device for surface modification of AISI304 Steel

A 2.8 kJ plasma focus device with a nitrogen gas filling and a copper anode capsulated by aluminum was used to modify the surface of AISI304 steel substrate, in order to improve its properties. The treatment was carried out using a various number of nitrogen plasma focus shots at a pressure of 0.5 mbar and at two steel sample distances (20 and 40 mm) from the anode. The plasma diagnostics was made using the voltage and current curves recorded by a voltage divider, Rogowskii coil, accompanied with calculations using a five phase radiative Lee model (RADPF5.15a) to determine the temperature and plasma density. The surface hardness of AISI304 steel was increased by ∼175% after plasma treatment and the thickness of the treated layers was about 1–2 μm. Results show that the surface hardness is increased with increasing shot number and decreased with increasing distance from the anode. Changes in surface morphology and the elemental composition were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).

Dense plasma focus ion-based titanium nitride coating on titanium

We report the synthesis of titanium nitride coating on a titanium substrate by utilizing energetic nitrogen ions emitted from a 2.3kJ dense plasma focus device for 30 focus shots. The number of nitrogen ions transferred to the sample by a single ion pulse of about 140ns duration in the energy interval (40–600keV) is about 1.09×1012 with a mean energy per ion of 58keV. The corresponding energy flux delivered to the titanium surface is estimated to be 6.17×1014keVcm−3ns−1 leading to a transient temperature rise of the top layer of about 5400K which helps layer growth. The coating is investigated on the basis of its morphological, compositional and hardness properties. X-ray diffraction analysis of the sample reveals the formation of a nanocrystalline titanium nitride coating having (111) and (200) plane reflections with an average crystallite size of 40nm. The compressive residual stresses in the nitride coating have been evaluated to be 2.80GPa and 6.81GPa corresponding to (111) and (200) plane orientations. A complete restructuring of the manually polished titanium substrate has been observed with appearance of nano-sized multidimensional granular surface morphologies. The thickness of the nitride coating is about 1μm, whereas the coating has a nitrogen content of 35.35at.% and 13.78±3.57wt.% and a surface hardness of 8.19GPa.

Characterization of carbon film by Raman spectroscopy

The deposition of amorphous carbon films is made on silicon substrates, using a low energy (1.4 kJ) dense plasma focus. The silicon substrates are placed in front of the graphite inserted anode at a 5 cm distance for different angular positions (0°, 8°, and 12°) with respect to the anode axis. The films are deposited using 25 focus shots at an optimum pressure of 0.75 mbar by using argon as working gas. The structural information of the deposited films is obtained by using Raman spectroscopy at room temperature with 785 nm line of a solid-state diode laser at an operating power of 100 mW. The analyses show the deposition of both graphite-type trigonal sp2 and diamond-type tetragonal sp3 films. The surface morphology is studied by using a scanning electron microscope. The irradiation by energetic high-fluence ions results in surface swelling of the substrate, increasing its roughness. With higher fluence, the surface damage is significant as a consequence of the excessive energy deposited on the substrate.

Carbonitriding of silicon using plasma focus device

Carbonitride thin films have been deposited on silicon substrate by the irradiation of energetic nitrogen ions emanated from dense plasma focus device. The carbon ions are ablated by the irradiation of relativistic electrons from the insert material (graphite) placed at the anode tip. The x-ray diffraction analysis demonstrates that a polycrystalline thin film consisting of various compounds such as Si3N4, SiC, and C3N4 is formed on the silicon (100) substrate. Crystallinity of different compounds decreases with the increase in angular positions (0°, 10°, and 20°). Raman spectroscopy shows the appearance of graphitic and disordered bands with silicon nitride and silicon carbide indicating the formation of carbonitride. Raman spectra also indicate that broadening of bands increases with the increase in focus deposition shots, leading to the amorphization of the thin film. The amorphization of the thin films depends on the ion energy flux as well as on the sample angular position. The scanning electron microscopy exhibits the damaging of the substrate surface at 0° angular position. The microstructure shows the tubular shape for higher ion dose (40 focus shots). At 10° angular position, a two phase phenomenon is observed with the ordered phase in the solid solution. A smooth and uniform surface morphology showing a small cluster is observed for the 20° angular position.

Synthesis of nano-crystalline zirconium aluminium oxynitride (ZrAlON) composite films by dense plasma Focus device

Zirconium aluminium oxynitride multiphase composite film is deposited on zirconium substrate using energetic nitrogen ions delivered from dense plasma Focus device. X-ray diffractometer (XRD) results show that five Focus shots are sufficient to initiate the nucleation of ZrN and Al 2O 3 whereas 10 Focus shots are sufficient to initiate the nucleation of AlN. XRD results reveal that crystal growth of nitrides/oxides increases by increasing Focus shots (up to 30 Focus shots) and resputtering of the previously deposited film is taken place by further increase in Focus shots (40 Focus shots). Scanning electron microscopic (SEM) results indicate the uniform distribution of spherical grains (∼35 nm). A smoother surface is observed for 20 Focus shots at 0° angular position. SEM results also show a net-type microstructure (thread like features) of the sample treated for 30 Focus shots whereas rough surface morphology is observed for 40 Focus shots. Energy dispersive spectroscopic profiles show the distribution of different elements present in the deposited composite films. A typical microhardness value of the deposited composite films is 5255 ± 10 MPa for 10 grams imposed load which is 3.3 times than the microhardness values of unexposed sample. The microhardness values of the exposed samples increases with increasing Focus shots (up to 30 Focus shots) and decreases for 40 Focus shots treatment due to resputtering of the previously deposited composite film. The microhardness values of the composite films decreases by increasing the sample's angular position.

Deposition of titanium nitride on Si(1 0 0) wafers using plasma focus

Titanium nitride thin films were deposited on Si(1 0 0) substrates by using a low energy (2.3 KJ) Mather-type plasma focus device. The composition of the deposited films was characterized by X-ray diffraction (XRD). The crystallite size has strong dependence on the numbers of focus shots. The crystallinity of TiN thin films is found to increase with increasing the number of focus shots. The effect of different number of focus shots on micro structural changes of thin films was characterized by Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM). SEM results showed net-like structure for film deposited for 15 numbers of shots, which are elongated grains of Si 3N 4 in amorphous form embedded into TiN crystals. The average surface roughness was calculated from AFM images of the thin films. These results indicated that the average surface roughness increased for films deposited with increased number of focus shots. The least crystallite size and roughness are observed for film deposited with 25 focus shots.

Dense plasma focus-assisted nitriding of AISI-304

Nitrogen ion implantation into AISI-304 stainless steel is carried out using a dense plasma focus device, operated at a charging voltage of 18 kV (discharge energy=1.45 kJ) with nitrogen filling at optimum pressure of 0.75 mbar. AISI-304 stainless steel samples placed axially above the anode tip are exposed to the ions for 10, 20 and 30 focus shots. X-ray diffraction (XRD), Vickers's micro hardness tester, scanning electron microscopy, and energy dispersive X-ray spectroscopy are used to explore the ion induced changes in the crystallographic structures, surface morphology, elemental composition and surface hardness of the ion irradiated samples. The XRD pattern confirms the formation of an expanded austenite phase, owing to nitrogen incorporated into the existing iron lattice. The results of micro hardness tester show that the hardness is increased about three times at an axial distance of 5 cm for 20 shots.

Deposition of titanium nitride on AISI-304 in a plasma focus environment

Polycrystalline, smooth, and hard thin films of TiN are successfully deposited on AISI-304 substrates using a 1.5 kJ Mather-type dense plasma focus device charged at 18 kV. The purpose of this study is to investigate the structural and mechanical properties of the TiN thin films in terms of ion dose and substrate position to establish the optimum deposition conditions. The films are analyzed using XRD, SEM, electron microprobe and micro-hardness testing. XRD confirms the deposition of a polycrystalline TiN thin film together with the emergence of an iron chromium nickel phase. The surface hardness-in comparison to the unexposed substrate-is found to increase up to 250% when a film is deposited using 30 focus shots at an axial distance of 6 cm. SEM micrographs show that the quality of the film is improved with an increasing number of focus shots. The constituent elements of the film are also confirmed by electron microprobe.