Plasma and ion beam methods such as gas and metal ion implantation, plasma immersion ion implantation (PIII), and metal plasma immersion ion implantation and deposition (MePIIID) are introduced as powerful tools to modify the properties of battery electrodes. Three kinds of rechargeable electrochemical cells have been investigated: the lead-acid cell, the nickel alkaline-electrolyte cell, and the lithium cell. It was experimentally shown that (i) metal ion implantation of Ti, V, Cr, Ni, and W into lead and lead-antimony electrodes reduced the corrosion current by more than one order of magnitude, (ii) cobalt ion implantation into nickel electrodes enhanced the interconversion of Ni(OH)2 to NiOOH and the associated cycle life, (iii) nitrogen-PIII resulted in the formation of a nitrided lithium layer on lithium which stabilized the surface against corrosion, (iv) MePIIID with a tungsten plasma reduced the pitting corrosion of aluminum, a current collector for a lithium battery.

Acoustic waves induced by an intensity-modulated focused ion beam (FIB) have been measured. The experiments were performed with Ga+ ions of 35 keV at a current of 3 nA and variable chopping frequency up to 10 MHz. The acoustic signals were detected by means of a piezoelectric sensor with integrated pre-amplifier. In the paper the experimental setup and the results of first measurements are presented. Evidence for FIB induced acoustic waves has been found.

We discuss changes in electronic structure and the topography of a graphite surface undergoing by a single ion impact. Protrusion-like regions (PLRs) found in a scanning tunneling microscope image disappeared in the same view of a noncontact atomic force microscope image. We measured tunneling current versus voltage characteristics to determine the density-of-states change in PLRs. We found that the density of states at the Fermi level of PLRs was greater than that of the intact surface. We therefore concluded that the PLRs were not actual topographical changes, but originated from electronic structural changes in semimetal to metal transition.

We report the results of using sputtering and negative carbon ion sources to prepare thin films of carbon nitride. In this work, we compare the structural, tribological, and optical properties of the carbon nitride films that were prepared by two different ion assisted techniques. In the first approach we used a magnetron gun to sputter deposit carbon in a nitrogen atmosphere. The second method utilized a beam of negatively charged carbon ions of 1 to 5 μA/cm2 current density impinging the substrate simultaneously with a positive nitrogen ion beam produced by a Kaufman source. We were able to synthesize microscopically smooth coatings with the carbon to nitrogen ratio of 1 : 0.47. These films possess wear rates lower than 5×10−7 mm3/Nm and friction coefficients in the range of 0.16 to 0.6. Raman spectroscopy revealed that the magnetron sputtered films are more structurally disordered than those formed with the negative carbon ion gun. FTIR showed the presence of the C≡N stretching mode in both types of films. Finally, spectroscopic ellipsometry produced films with dielectric constants as low as 2.3 in the photon energy range from 1.2 to 5 eV.

The sputter losses during growth of carbon nitride thin films using mass selected ion beam deposition of C+ and N+ ions with energies between 20 eV and 500 eV are studied. Depending on the ion energy 35 – 100 % of C+ but only 3 – 35 % of N+ ions are incorporated in the films. Thus the films are always strongly nitrogen-deficient. To suppress the preferential loss of nitrogen we introduce the concept of continuously growing surface protective layers. Starting from a diamond-like carbon film as substrate, carbon nitride films are deposited using 100 eV 12C+ and 1 keV 14N+ ions, so that the growing films are always covered with a 1–2 rm thick protective layer of amorphous carbon. In this case we observe an increased nitrogen incorporation yielding to films with average film composition of C2N.

Vacuum-arc deposition is used to deposit multilayer carbon films by modulating the sample bias during deposition. The effect of varying the sublayer thickness in multilayer films consisting of alternating layers of “hard” (68.4 GPa, -100 V bias) and “soft” (27.5 GPa, -2000 V bias) was investigated. Films consisting of equal thickness layers of hard and soft material and an individual layer thickness varying from 10 to 35 nm were deposited. Mechanical property measurements were obtained by finite element modeling of nanoindentation load-displacement curves. The film hardness values were about 20% below the average of the component layers and relatively independent of the layer thickness. TEM investigation revealed deterioration of the multilayer structure when the sublayer thickness was below 15 nm due to implantation damage of the hard layers caused by the energetic C+ ions of the soft layers (-2000 V bias) deposited over them. Pin-on-disk wear tests show that the wear rate drops when sublayer thickness is decreased below 20 nm and remains constant with further decreases in the layer thickness.

Amorphous, 700 nm thick, diamond-like carbon coatings containing silicon (Si-DLC), farmed by Ar+ ion beam assisted deposition (IBAD) on silicon substrates, were annealed in air at temperatures ranging from room temperature to 600°C for 30 minutes. RBS analysis showed that the composition of the films remained the same up to 200°C, but at higher temperatures the Si-DLC coatings began to oxidize at the outer surface of the coating, forming a surface layer of SiO2. After in-air annealing at 600°C the coating had been completely converted to SiO2, with no trace of carbon seen by RBS. FTIR spectra of the unannealed coatings showed a very broad mode typical of Si-DLC bonding as well as some absorption features associated with Si and SiO2. Above 200°C the transmission mode shifted to higher frequencies which may be caused by the growth of SiO2 and the decrease of the Si-DLC film thickness. The room temperature ball-on-disk friction coefficient of the coating against a 1/2′′ diameter 440 C steel ball at 1 N load ranged from 0.2 for the original coating up to 0.5 after a 100° anneal and returned to 0.2 after annealing at 200–400°C and fell to 0.12 after a 500°C exposure. The average Knoop microhardness (uncorrected for substrate effects) was 10 GPa (1,000 KHN) for coatings annealed at temperatures as high as 400°C. All coatings up to 500 °C passed the qualitative “Scotch Tape” test.

Thin films of diamond-like carbon have been grown by pulsed laser deposition using a Nd:YAG laser at 532 nm. Time-of-flight mass spectroscopy was used to investigate the effects of laser power density and background gas pressure on the plume characteristics including the species in the plume and the kinetic energy distribution of each species. We found that with increasing laser power density (1) the relative amount of C+ ions increases, (2) the kinetic energy distributions of C+ get broader and can be deconvoluted into fast and slow components, and (3) the kinetic energy of the fast component of C+ ions increases from several to 40 eV. The resistivity and the local carbon bonding in films grown under these same conditions were also characterized. It was found that there is direct correlation between the characteristics of fast part of C+ ions in the plume and the diamond-like properties of the thin films. Under optimal growth conditions diamond-like carbon films with a large fraction of sp3 bonding can be prepared, although the maximum fraction appears to saturate at 70%. The implications of these results are discussed.

Diamond-like carbon films with mechanical properties approaching those of diamond have been consistently produced by cathodic vacuum arc based techniques. These films have been successfully used in applications where enhanced hardness and wear resistance are required Such DLC films have two major drawbacks that prevent their application in other areas: a high level of internal stresses, which promotes failure by spallation of thick films; and the loss of mechanical properties at temperatures higher than 300°C. In this paper we describe the effect of doping elements on the room-temperature mechanical properties and on the thermal stability of DLC films upon annealing in air. The effect of the presence of W and Ti was investigated and compared to pure DLC. The films were produced by dual-source metal plasma immersion ion implantation and deposition with magnetic filtering to remove macroparticles from the plasma; dopant content was controlled by varying the relative pulse duration of the two plasma sources. Microstructural and chemical characterization of the films are presented.

Using a newly developed ion beam apparatus, PANDA (Positive And Negative ions Deposition Apparatus), carbon nitride films were prepared by simultaneous deposition of mass-analyzed low energy positive and negative ions such as C2-, N+, under ultra high vacuum conditions, in the order of 10−6 Pa on silicon wafer. The ion energy was varied from 50 to 400 eV. The film properties as a function of their beam energy were evaluated by Rutherford Backscattering Spectrometry (RBS), Fourier Transform Infrared spectroscopy (FTIR) and Raman scattering. From the results, it is suggested that the C-N triple bond contents in films depends on nitrogen ion energy.

An ultra high vacuum ion beam system, consisting of a 20 cm diameter Rf excilted (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including; infrared windows, silicon nitride, polycrystalline diamond, 304 and 316 stainless steels, 440C and M50 steels, aluminum alloys, and polycarbonates; by depositing different chemical compositions of diamond-like carbon films. The influences of ion energy, Rf power, gas composition (H2/CH4 , Ar/CH4 and O2/CH4/H2), on the diamond-like carbon characteristics has been studied. Particular attention was focused on adhesion, environmental effects, IR(3–12 μm) transmission, coefficient of friction, and wear factors under spacelike environments of diamond-like carbon films on various substrates. A quadrupole mass spectrometer was utilized to monitor the ion beam composition for quality control and process optimization.

We present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.

The surface of Ti-6Al-4V (Ti64) alloy has been modified using beamline implantation of boron. In separate experiments, Ti64 has been implanted with nitrogen using a plasma source ion implantation (PSII) technique utilizing either ammonia (NH 3), nitrogen (N2), or their combinations as the source of nitrogen ions. Beamline experiments have shown the hardness of the N-implanted surface saturates at a dose level of ˜4× 1017 at/cm2 at ˜10 GPa. The present work makes comparisons of hardness and tribological tests of (1) B implantation using beamline techniques, and (2) N implanted samples using ammonia and/or nitrogen gas in a PSII process. The results show that PSII using N2 or NH3 gives similar hardness as N implantation using a beamline process. The presence of H in the Ti alloy surface does not affect the hardness of the implanted surface. Boron implantation increased the surface hardness by as much as 2.5x at the highest dose level. Wear testing by a pin-on-disk method indicated that nitrogen implantation reduced the wear rate by as much as 120x, and boron implantation reduced the wear rate by 6.5x. Increased wear resistance was accompanied by a decreased coefficient of friction.

Fired rails from electromagnetic railguns show severe damage from arcing and tribological mismatch. We have fabricated and studied several different nanoscale multilayered materials as possible routes to improve the thermal transport and thermomechanical properties of the rail and armature materials. A vacuum-arc-based plasma deposition technique with wide control of ion energy was used for the film synthesis, and high-energy high-dose (energy up to ˜ 150 keV, dose up to ˜ 1 × 1017cm−2) metal ion implantation was also used. The multilayered film structures formed and investigated included sublayers of Ti, TiCo, ZrN, TaN and dlc (diamond-like carbon) in the following combinations: (i) ZrN on TiCo on TaN on dlc on a Cu substrate, (ii) ZrN on TiCo on TaN on dlc on an Al substrate, (iii) TiN on TiCo on TaN on a stainless steel substrate, and (iv) Ti on TiCo on a stainless steel substrate. Individual sublayer film thickness was in the range of 400Å-7μ. The surfaces were characterized by SEM, TEM, RBS, high energy electron diffraction, arid microhardness measurements. Significant improvements in the material surface properties were obtained for virtually all of the surface structures investigated. Here we outline the material synthesis and surface modification techniques used and the materials characterization results obtained.

We have used pulsed vacuum arc deposition to prepare TixCy films and multilayer structures of TixCy / diamondlike carbon (DLC) in a dual plasma source set-up. The composition of the monolithic films was controlled by varying the pulse duration of each plasma gun. During the deposition, a repetitively pulsed bias voltage was applied to the substrate in order to improve the adhesion to the substrate and between the individual layers. For the multilayers, the carbon and Ti guns were synchronously pulsed during deposition of the TixCy, and the Ti gun was not operated during the DLC deposition. Multilayers with different periodicities were synthesized. The deposited films were analyzed by various techniques including XPS, AES, TEM, EELS, and XRD to characterize the composition, bonding states, and microstructure. Special attention was given to the interface thickness in relation to the applied bias voltage. Tribological properties such as friction coefficient and wear resistance were measured, and correlated to the composition and microstructure of the films.

Al / AI-N / AIN compositional gradient thin film was deposited on a Si(100) substrate at room temperature by ion-beam assisted deposition method, with a diminishing ion beam current from 1.4 to 0 mA at increments of 0.3 mA in order to gradually decrease the nitrogen to aluminum ratio at the substrate. The gradual Al and AIN variation in composition was shown by the change of the Al / N atomic ratio analysed by the energy dispersive X-ray spectroscopy(EDX) and the X-ray photoelectron spectroscopy (XPS) in the cross section of the film. The formation of crystalline Al metal and AIN ceramic layer on the Si substrate was revealed by X-ray diffraction(XRD). The cross sectional image taken by high resolution transmission electron microscope (HRTEM) showed a nano-sized crystalline AI-N ceramic material and the flat interface between the Si substrate and the AIN film.

Titanium nitride (TiN) film for the bearings and seals used in rotating machinery has been developed by the dynamic-ion-beam-mixing (DM) process, which combines Ti vapor deposition with simultaneous nitrogen ion beam irradiation. In this study, the tribological properties of the DM-TiN film on martensitic stainless steel (SS) were investigated for application on the bearings of submerged pumps. The critical contact pressure for seizure, wear resistance and friction coefficient properties of DM-TiN film paired with cast iron were investigated under practical sliding conditions, and compared with the hard surface materials of nitriding AISI 420 SS and nitriding 41CrAlMo74 (CrAlMo) steel. The results show that DM-TiN film is superior to these nitriding steels in surface contact pressure for seizure and wear resistance.

Mechanical and tribological properties of chromium-nitrogen films deposited by ion beam assisted deposition (IBAD) were investigated. The films were deposited reactively, i.e., via chromium evaporation with concurrent nitrogen ion beam bombardment, on stainless steel substrates at low deposition temperatures (<200°C). Two primary deposition regimes, with differing Cr/N atom-to-ion arrival ratios, were investigated: approximately 0.8–1.0 and 2.5–3.0. Rutherford Backscattering Spectroscopic analysis showed the lower arrival ratio films to be essentially stoichiometric CrN, whereas films deposited at higher arrival ratios were Cr-rich with Cr/N ratios of about 3:1. Both films were fine grained polycrystalline (typically 5–20 nanometer crystal dimension). The stoichiometric films were approximately two times harder than the Cr-rich films., based on nanohardness indentation measurements, and possessed higher residual stress levels. Both film types substantially improved the wear resistance of stainless steel disks, based on the results of ball-ondisk wear tests against ruby balls. The best performance was obtained with Cr-rich films, which exhibited a very low wear rate and lower friction than either the stoichiometric film or the uncoated steel.

The role of aluminum in negating the adverse effect of alkali species on the oxidation resistance of Si3N4 ceramics was investigated by exposing unimplanted and aluminum-implanted (1 and 5 at.%) Si3N4 samples to a sodium nitrate (95 ppm)-dry oxygen gas mixture at 1. atm and at 900°1100°C. Oxidation of unimplanted Si3N4 was rapid and linear with an activation energy of 57 kJ/mol. In contrast, samples implanted with aluminum exhibited a considerably reduced oxide growth which was parabolic in nature with activation energies of 103–112 kJ/mol. The morphological characteristics of the oxide layer also showed marked improvement as the aluminum concentration increased.

The influence of particle bombardment on surface reactivity is examined by using the reaction of CO on the Ni(111) surface as a model system. Thermal desorption studies shows that a large amount of residual CO may be deposited on the surface during ion bombardment. An appreciable amount of oxygen can be produced on the surface by collision-induced CO dissociation. A new dlesorption state of CO is also formed. The activation energy for CO desorption from this new state is estimated to be about 90 kJ/mol, which corresponds to a decrease of the C-Ni bond energy of 25 – 30 kJ/mol as the sample evolves from a smooth to a damaged state. The dipole-dipole repulsion is present between CO molecules adsorbed on the ion-bombarded surface, which causes CO to desorb at a lower temperature for higher CO exposures. Under similar bombardment conditions, the sticking probability of CO on the bombarded surface decreases with decreasing momentum of the impinging particle.