Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2019
Abstract The application of wear resistant metal nitride coatings, typically 2–5 μm thick, is a w... more Abstract The application of wear resistant metal nitride coatings, typically 2–5 μm thick, is a well-established strategy, employed for prolonging service life of cutting tools, twist drills, taps, dies. Although TiN is an established coating for such applications, in recent years attention has focused on a more diverse range of metal nitride coatings. Specifically, modifications to the TiN structure through the addition of C to produce TiCN are well established for improvement in properties such as friction coefficient and wear rates. Further improvements in tribological performance are expected by modifying the surface using ion implantation. In this exploratory study, TiCN coatings were deposited onto polished AISI 316 stainless steel substrates using commercially available physical vapor deposition technology. Coated samples were ion implanted with a range of metal ions to include Mo, Nb, W, Zr and Cr using the metal vapor vacuum arc (MEVVA) technique. Ions were implanted at a constant dose of 4 × 1016 ions/cm2. The range of techniques used to characterize the implanted layers included x-ray diffraction, Rutherford backscattering, and optical and atomic force microscopy. Dry sliding friction and wear behavior of implanted coatings was assessed using pin on disc equipment. The results showed that, with some exceptions, ion implantation generally improved friction and wear; in particular, implantation with Nb reduced stress levels, grain size, surface roughness, friction and wear rates.
The cold plasma techniques for deposition of various types of protective coatings are reviewed. T... more The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.
... substrates. KP Purushotham a , Liam P. Ward Corresponding Author Contact Information , E-mail... more ... substrates. KP Purushotham a , Liam P. Ward Corresponding Author Contact Information , E-mail The Corresponding Author , a , Narelle Brack b , Paul J. Pigram b , Peter Evans c , Hans Noorman c and Rafael R. Manory d , 1. ...
The fluorescence emission spectra from the plasma plume induced by ArF excimer laser irradiation ... more The fluorescence emission spectra from the plasma plume induced by ArF excimer laser irradiation of YBa2Cu3O7‐x was studied and compared to the spectra of Y, YO, Cu, CuO, and YCuO under similar conditions. The only compound detected in the Y‐Ba‐Cu‐O ablated material spectra was YO. Spatially resolved measurements from the plasma plume emanating from the irradiated superconducting material were performed also as a function of distance from the surface.The effect of laser ablation on the morphology and composition of the irradiated YBa2Cu3O7‐x material was studied by SEM and EDAX. It was found that the 1‐2‐3 composition ratio of the near surface region was maintained after ablation. Changes in the morphology were observed in the track region and three distinctive regions could be identified as a function of distance from the beam center.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2002
ABSTRACT Hafnium oxide films were grown by ion beam assisted deposition on water-cooled Si (100) ... more ABSTRACT Hafnium oxide films were grown by ion beam assisted deposition on water-cooled Si (100) substrates, under conditions of oxygen starvation, using hafnium vapor and an oxygen ion beam. The transport ratio (TR), i.e., the ratio between the arrival rate of hafnium to that of oxygen, was varied between 0.5 and 10, and ion energy was varied between 1 and 20 keV. The films were analyzed using x-ray diffraction and x-ray photoelectron spectroscopy. Films having the CaF2 cubic structure with a lattice parameter of about 0.512 nm were repeatedly obtained. In addition, at 20 keV ion energy and TR values of 4 and above, films with a tetragonal structure were obtained. The latter structure, believed to be a distortion of the cubic structure, has a c/a ratio of 1.01 and its space group is considered to be different from the high temperature tetragonal HfO2 structure. The new tetragonal structure also presents high Knoop hardness, with values between 15 and 25 GPa. Substrate rotation speed was found to affect the structure and the orientation of the films. All films exhibit a stoichiometry in the vicinity of HfO1.6, with the tetragonal films apparently being Hf2O3. These structures are attributed to a very fast cooling rate during film formation. Films deposited without substrate water cooling, or with substrate heating up to 500 °C contain a large component of the monoclinic phase. The new cubic and tetragonal structures are stable at room temperature and upon annealing up to 450 °C in vacuum, but convert to the monoclinic structure upon annealing at 500 °C in air, indicating that their low oxygen content is a key factor for their stability.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2019
Abstract The application of wear resistant metal nitride coatings, typically 2–5 μm thick, is a w... more Abstract The application of wear resistant metal nitride coatings, typically 2–5 μm thick, is a well-established strategy, employed for prolonging service life of cutting tools, twist drills, taps, dies. Although TiN is an established coating for such applications, in recent years attention has focused on a more diverse range of metal nitride coatings. Specifically, modifications to the TiN structure through the addition of C to produce TiCN are well established for improvement in properties such as friction coefficient and wear rates. Further improvements in tribological performance are expected by modifying the surface using ion implantation. In this exploratory study, TiCN coatings were deposited onto polished AISI 316 stainless steel substrates using commercially available physical vapor deposition technology. Coated samples were ion implanted with a range of metal ions to include Mo, Nb, W, Zr and Cr using the metal vapor vacuum arc (MEVVA) technique. Ions were implanted at a constant dose of 4 × 1016 ions/cm2. The range of techniques used to characterize the implanted layers included x-ray diffraction, Rutherford backscattering, and optical and atomic force microscopy. Dry sliding friction and wear behavior of implanted coatings was assessed using pin on disc equipment. The results showed that, with some exceptions, ion implantation generally improved friction and wear; in particular, implantation with Nb reduced stress levels, grain size, surface roughness, friction and wear rates.
The cold plasma techniques for deposition of various types of protective coatings are reviewed. T... more The cold plasma techniques for deposition of various types of protective coatings are reviewed. The main advantage of these techniques for deposition of ceramic films is the lower process temperature, which enables heat treating of the metal prior to deposition. In the field of surface hardening of steel, significant reduction of treatment time and energy consumption were obtained. A simple model for the plasma - surface reactions in a cold plasma system is presented, and the plasma deposition techniques are discussed in view of this model.
... substrates. KP Purushotham a , Liam P. Ward Corresponding Author Contact Information , E-mail... more ... substrates. KP Purushotham a , Liam P. Ward Corresponding Author Contact Information , E-mail The Corresponding Author , a , Narelle Brack b , Paul J. Pigram b , Peter Evans c , Hans Noorman c and Rafael R. Manory d , 1. ...
The fluorescence emission spectra from the plasma plume induced by ArF excimer laser irradiation ... more The fluorescence emission spectra from the plasma plume induced by ArF excimer laser irradiation of YBa2Cu3O7‐x was studied and compared to the spectra of Y, YO, Cu, CuO, and YCuO under similar conditions. The only compound detected in the Y‐Ba‐Cu‐O ablated material spectra was YO. Spatially resolved measurements from the plasma plume emanating from the irradiated superconducting material were performed also as a function of distance from the surface.The effect of laser ablation on the morphology and composition of the irradiated YBa2Cu3O7‐x material was studied by SEM and EDAX. It was found that the 1‐2‐3 composition ratio of the near surface region was maintained after ablation. Changes in the morphology were observed in the track region and three distinctive regions could be identified as a function of distance from the beam center.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2002
ABSTRACT Hafnium oxide films were grown by ion beam assisted deposition on water-cooled Si (100) ... more ABSTRACT Hafnium oxide films were grown by ion beam assisted deposition on water-cooled Si (100) substrates, under conditions of oxygen starvation, using hafnium vapor and an oxygen ion beam. The transport ratio (TR), i.e., the ratio between the arrival rate of hafnium to that of oxygen, was varied between 0.5 and 10, and ion energy was varied between 1 and 20 keV. The films were analyzed using x-ray diffraction and x-ray photoelectron spectroscopy. Films having the CaF2 cubic structure with a lattice parameter of about 0.512 nm were repeatedly obtained. In addition, at 20 keV ion energy and TR values of 4 and above, films with a tetragonal structure were obtained. The latter structure, believed to be a distortion of the cubic structure, has a c/a ratio of 1.01 and its space group is considered to be different from the high temperature tetragonal HfO2 structure. The new tetragonal structure also presents high Knoop hardness, with values between 15 and 25 GPa. Substrate rotation speed was found to affect the structure and the orientation of the films. All films exhibit a stoichiometry in the vicinity of HfO1.6, with the tetragonal films apparently being Hf2O3. These structures are attributed to a very fast cooling rate during film formation. Films deposited without substrate water cooling, or with substrate heating up to 500 °C contain a large component of the monoclinic phase. The new cubic and tetragonal structures are stable at room temperature and upon annealing up to 450 °C in vacuum, but convert to the monoclinic structure upon annealing at 500 °C in air, indicating that their low oxygen content is a key factor for their stability.
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Papers by Rafael R Manory