Surface Free Energy of Cubic Boron Nitride Films Deposited on Nanodiamond (original) (raw)
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Surface Chemistry, Microstructure, and Tribological Properties of Cubic Boron Nitride Films
This report deals with the surface chemistry, microstructure, bonding state, morphology, and friction and wear properties of cubic boron nitride (c-BN) films that were synthesized by magnetically enhanced plasma ion plating. Several analytical techniques-x-ray photoelectron spectroscopy, transmission electron microscopy and electron diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, and surface profilometry-were used to characterize the films. Sliding friction experiments using a ball-on-disk configuration were conducted for the c-BN films in sliding contact with 440C stainless-steel balls at room temperature in ultrahigh vacuum (pressure, 10 -6 Pa), in ambient air, and under water lubrication. Results indicate that the boron-to-nitrogen ratio on the surface of the as-deposited c-BN film is greater than 1 and that not all the boron is present as boron nitride but a small percentage is present as an oxide. Carbon, oxygen, tungsten, and argon contaminants can be introduced to the surface of the as-deposited c-BN film during the reactive ion-plating process.
Formation of cubic boron nitride films by r.f. magnetron sputtering
Surface and Interface Analysis, 2002
Boron nitride thin films have been deposited on silicon by tuned substrate r.f. magnetron sputtering from a sintered hexagonal BN target using a mixture of Ar (90%) and N 2 (10%) as sputtering gas at different substrate bias conditions. The deposited films have been characterized by Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). Both FTIR and XPS results show that the formation of nearly pure cubic boron nitride films were achieved when the films were deposited by a two-step process at a lower substrate bias voltage after the initial formation of the cubic boron nitride layer. Also, as indicated by FTIR measurements, this two-step process caused a reduction of the residual stress in the deposited films and no re-sputtering effects were present during the cubic BN growing process.
Structural and elastic properties of cubic boron nitride films
Surface and Coatings Technology, 2002
A thick, cubic phase, boron nitride film was deposited on a (100) Si wafer kept slightly above room temperature, by radio frequency (rf) magnetron sputtering. The rf target power was 150 W and the substrate bias voltage was y100 V. The film composition was checked by Auger electron spectroscopy (AES); the short-range order was investigated by Fourier transform infrared spectroscopy (FTIR) and micro-Raman spectroscopy. The film structure was assessed by glancing angle X-ray diffraction (GXRD). The elastic constants of the film were measured by surface Brillouin spectroscopy (SBS). To improve the visibility of Raman and Brillouin signals from cBN, the film was deposited onto a 600-nm thick titanium interlayer. The observed degradation of Raman features with respect to single crystal cBN is attributed to disorder and phonon confinement in our sample. Reliable values for the Young's modulus E and the shear modulus G of cBN were obtained from SBS. Results from nanoindentation measurements on the same film are compared to SBS results.
Journal of Applied Physics, 2003
The elastic and mechanical properties of high-quality cubic boron nitride ͑cBN͒ films with a few microns thickness and submicron grain size grown on silicon substrates by chemical vapor deposition were determined by measuring the dispersion of surface acoustic waves propagating along the surface of the layered system. The values are compared with those obtained with an ultralow load indenter ͑Triboscope͒. Specifically, the hardness, Young's modulus and density of the film were measured.
Nano-Scale, Multi-Functional, Cubic Boron Nitride Coatings
Nato Science Series, 2006
Protective coatings for tools and components are nowadays required in an increasingly demanding and sophisticated profile with respect to the desired mechanical, tribological, physical or chemical properties. Frequently, the necessary requirements can only be realized by multi-functional coatings through a nano-scale thin film design and the selection of materials with outstanding properties. Cubic boron nitride (c-BN) is superhard, has a chemical stability against ferrous metals at high temperatures, a large thermal conductivity and is a promising protective coating for cutting tools, increasing operation lifetime and cutting speed. It can be produced by physical vapour deposition or by plasma assisted chemical vapour deposition. Up to now, for the formation of the cubic phase ion bombardment is necessary. The nucleation and the subsequent growth of the cubic phase can be described independently of the deposition method by the ion energy, ion current density, angle of incidence of the ions, growth rate, and substrate temperature. The strong ion bombardment generates a high compressive stress, which can be reduced by optimisation of deposition parameters, deposition at high substrate-temperature, post-annealing, post-ion implantation, changing of deposition parameters after nucleation of c-BN, addition of a third element, and nano-composite coatings consisting of c-BN and diamond-like carbon. Based on these general stress reduction mechanisms, different coating concepts are discussed allowing the production of thick c-BN coatings with reduced compressive stress and good adhesion.
Thin films of cubic boron nitride (cBN) were deposited from a mixture of diborane (B 2 H 6 ), nitrogen and argon gas by inductively coupled radio frequency (RF) plasma chemical vapor deposition. Ion bombardment is a necessary condition for the growth of cubic phase. A series of samples were grown by changing the substrate bias voltage and the input RF power. The films were characterized by studying Fourier transformed infrared spectroscopy (FTIR) and the glancing angle X-ray diffraction pattern. XRD spectra showed clear reflection from the cubic phase up to (311). Lattice distortion was observed due to the presence of compressive stress in the films. The threshold of the window of bias voltage for the synthesis of cubic phase was found to decrease when an axial magnetic field of 500 G was applied to the plasma. This red shift of the substrate bias, when the plasma was enhanced magnetically, supported the momentum transfer model for the growth of cubic phase. D
Microstructure and stress investigations of cubic boron nitride thin films
Diamond and Related Materials, 1998
The hypothesis of a stress-induced phase transtbrmation from a basal h-BN (hexagonal boron nitride) layer is one of the most currently accepted to explain the synthesis of c-BN (cubic boron nitride) films deposited under ion bombardmenl. In the present work, an original method has been used to correlate the phase evolution and the in-depth distribution of stress within the film. This method was based on the t~omplementary use of reactive ion etching, quantitative FTIR and substrate curvature measurements. In addition, the structural organization of these fihns was also studied by in situ Reflection Electron Energy Loss Spectroscopy (REELS) analyses and REELS depth-profile. The results showed a layered structure exhibiting a pure c-BN volume lying between an upper zone of 3-4 sp-" bonded monolayers and an h-BN basal layer. The purity of the c-BN volume was confirmed by HRTEM analyses revealing also nanocrystallized grains with (111) planes parallel to the growth direction, indicating a (1101 texture perpendicular to the substrate. The stress distribution within the film emphasized a high, nearly homogeneous stress in the major part of the c-BN volume. In the sp" basal layer, a sharp peak of very high compressive stress is located, while an interfacial zone corresponding to the transition from h-BN to c-BN is lbund to retain a very low stress value. This paper reports a new contribution to the study of the mechanism of the slress-induced nucleation of c-BN films deposited under ionic irradiation, and tends to valid this mechanism proposed by McKenzie. ~ 1998 Elsevier Science S.A.
Constitution of thick oxygen-containing cubic boron nitride films
Surface and Coatings Technology, 2006
A novel method based on reactive magnetron sputtering and specifically devoted for the deposition of thick, adherent cubic boron nitride (c-BN) coatings on silicon substrates was developed. Through controlled incorporation of a small amount of oxygen into the deposition process, the ultrahigh compressive stress usually appearing in c-BN was effectively reduced down to −3 GPa, whereas the c-BN content was nearly unaffected. This allowed consequently 2 μm thick c-BN to be grown on top of a coating system initiated with a boron-rich base layer followed by a nucleation layer with gradient chemical composition.
Surface and Coatings Technology, 2006
Thin films of boron nitride (BN) have been deposited at low temperature (below 300°C) by microwave plasma-enhanced chemical vapor deposition (PECVD), using borane dimethyl amine, as boron precursor. The plasma was composed of a mixture of argon and nitrogen and was excited with a microwave power. In addition, a radiofrequency signal was applied to the substrate holder in order to negatively bias the sample during the deposition process. The characterization has been performed by infrared transmittance spectroscopy, and the influence of the bias on the deposition of the films has been studied. We have observed that the behaviour of the layers is that of an anisotropic uniaxial medium, and that they are composed of a collection of nanocrystallites of the hexagonal phase. These crystallites are textured with the very same orientation of their caxis relative to the normal of the sample. By performing the IR transmittance measurements at oblique incidence, additional bands of absorption related to longitudinal optical vibration modes allow us to determine very easily this texturation. The applied bias is shown to have a direct influence on it, the larger the voltage, the more the crystallites are oriented parallel to the sample surface, until a sputtering regime is reached at an even higher voltage.