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In this study, pseudo-elastic Ni 50.8 at.%-Ti alloy sheets of 1000 μm thickness were coated with 10 μm thick refractory metal thin films (Mo, Ta and Nb thin films, respectively), by nonreactive d.c. magnetron sputtering. These thin films were characterized with regard to their microstructure, morphology and selected mechanical properties. Microstructural characterization of the thin films included X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. SEM images show, that Mo thin films grow in a densely packed structure with columnar grains. Pole figure analyses reveal a distinct (110) texture of the deposited Mo thin films on the NiTi substrate. The Mo thin films exhibit relatively large crystallite sizes, 290–300 nm. Ta and Nb thin films show XRD reflections of various lattice planes, i.e. polycrystalline b.c.c. structures, with preferential (110) orientation. Both of these thin films grow with much smaller crystallite size in comparison to the Mo thin films, 30–40 nm. The Young's Modulus of both the thin films and thin film/substrate composites were investigated on various scales. For this purpose, indentation experiments were performed using both nano- and microindentation techniques. A comparison of the values of the Young's Modulus of the thin film materials (in bulk, literature data) and the results obtained from nanoindentation shows a very good agreement between the measured data and bulk data. Progressive scratch tests were used to evaluate the adhesion of the thin film materials on the NiTi substrate. These scratch tests suggest that the metallic thin films undergo plastic deformation at larger normal forces. However, no thin film delamination is observed, independent of the material combinations and testing conditions applied. [ABSTRACT FROM AUTHOR]

To improve the electrochemical properties of Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 (NMC) like Lithium-diffusion rate or rate capability one way is to increase the surface between the cathode and electrolyte. By sputter etching of stainless steel substrates the surface topography is varied. Lithium-rich Li-Ni-Mn-Co-O thin film cathodes are deposited onto these modified stainless steel substrates by non-reactive r.f. magnetron sputtering from a ceramic Li 1.14 (Ni 0.37 Mn 0.18 Co 0.32 )O 1.19 target. Microstructure and electrical properties were characterized by X-ray diffraction (GIXRD), Raman spectroscopy, Atomic-force microscopy (AFM) and impedance spectroscopy (IS). The substrate roughness was increased from R a = 4 nm to R a = 63 nm after 180 min of sputter etching. The crystal orientation wasn’t influenced significant by the pre deposition surface topography modification. The results show that the activation energy E A of the conductivity mechanism is 0.23 eV, independent of the pre-deposition sputter etching treatment. Also the pre-deposition sputter etching increases the conductivity from 1.49·10 −11 Scm −1 to 1.75·10 −10 Scm −1 at 20 °C. Correlations between process parameters, microstructure and electrical behaviour are discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract: For the application in high-frequency micromagnetic devices, the permeability and resonance frequency of ferromagnetic components is of high interest. It is dominantly influenced by different factors, the external field and direction and the domain distribution, shape and orientation. By the use of micromagnetic simulation, the domain pattern in films was determined and the effective permeability was calculated. The results of the calculations were compared with the domain shape of patterned microstructures of thin FeCoTaN-films, which were deposited onto oxidised silicon substrates by reactive r.f.-magnetron sputtering by employing 6-in Fe37Co46Ta17 targets. To achieve a high-frequency suitability, the films have to be annealed in a static magnetic field of 50mT between 400 and 500°C, which are typical temperatures used in CMOS processes, to induce an in-plane uniaxial anisotropy needed for the high-frequency performance. Magnetic softness was obtained by producing amorphous or nanocrystalline films, and additionally, by aspiring low magnetocrystalline anisotropies for, e.g., certain Fe/Co fractions. The unpatterned films with a lateral dimension of 5×5mm2 were measured in a strip line permeameter in a frequency range up to 5GHz and exhibited ferromagnetic resonance frequencies between 2 and 2.5GHz within a low-loss permeability spectrum (low width of imaginary part of permeability). For possible integrations in passive microelectronic components the films were patterned to a few tenths of micrometers by near ultra-violet lithography and plasma beam etching, and then consequently annealed to obtain the static and dynamic magnetic properties. To influence the amount of closure domains, designs were conceived to influence the domain formation by creating additional internal boundaries. As a result, the ferromagnetic resonance frequency and the effective permeability are strongly driven by internal and external boundaries. [Copyright &y& Elsevier]

Abstract: Ferromagnetic Fe–Co–Hf–N nanocomposite films were investigated concerning their microstructure-dependent frequency behaviour. To modify the composition, the films were deposited by reactive RF magnetron sputtering by using three different 6in. targets with various Hf fractions. The films were post-annealed up to 600°C in a static magnetic field to induce an in-plane uniaxial anisotropy and to obtain different crystal sizes. Depending on the annealing temperature, high-frequency losses were investigated by considering the full-width at half-maximum (FWHM) Δf eff of the imaginary part of the frequency-dependent permeability which showed a resonance frequency f FMR of 2.3GHz for an in-plane uniaxial anisotropy field H u of 4mT. The FWHM in correlation with the damping parameter α eff is discussed, e.g., in terms of two-magnon scattering. Damping occurs due to film inhomogeneity in magnetisation and uniaxial anisotropy caused by a magnetocrystalline anisotropy H a and/or non-magnetic phases. This will result in homogenous or even inhomogeneous resonance line broadening if additional and resonance as well as precession frequencies of independent grains arise. [Copyright &y& Elsevier]

Abstract: The design and synthesis of Al–Cr–O–N thin films in a metastable solid solution strengthened α-(Al1−x,Crx)2+δ(O1−y,Ny)3 microstructure are described. The deposition experiments were carried out by reactive r.f. magnetron sputtering in an argon–oxygen–nitrogen atmosphere for the sputtering from a segmented target, composed of an Al half plate and a Cr half plate. The constitution, microstructure and Vickers micro hardness of the coatings are discussed in dependence of the deposition parameters and the elemental composition. The range of α-(Al1−x,Crx)2+δ(O1−y,Ny)3 phase formation is shifted to higher Cr/(Al+Cr) ratios with increasing nitrogen gas flow. A γ-Al–Cr–O–N phase is formed at high total gas pressures and low Cr/(Al+Cr) ratios. The solid solution strengthening in the quaternary material system leads to a significant Vickers micro hardness increase compared to α-(Al1−x,Crx)2O3 coatings deposited in the same PVD machine under corresponding process parameters. The α-(Al1−x,Crx)2+δ(O1−y,Ny)3 thin films offer an additional restraint of the lattice by the incorporation of nitrogen and therefore higher Vickers micro hardness values are measured compared to the Al–Cr–O material system. [Copyright &y& Elsevier]

Abstract: Nanocrystalline hard coatings of the system V–Al–C–N with an f.c.c. metastable solid solution (V,Al)(N,C) microstructure were deposited by non-reactive r.f.-magnetron sputtering of a ceramic compound target (composition: 60mol.% VC and 40mol.% AIN) in a pure argon discharge at 1.1Pa. The chemical composition of the as-deposited coatings was determined by electron probe micro analysis (EPMA). The microstructure of the thin films was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The influence of a moderate argon ion bombardment during thin film deposition, realized through the variation of the argon ion energy in the range 20eV–170eV, as a means to adjust the adatom surface mobility and surface diffusion processes, on the microstructure evolution and on the Vickers micro-hardness is discussed. The conditions for the formation of a metastable solid solution f.c.c. (V,AI)(C,N) thin film microstructure are described in terms of surface processes during film growth and thermodynamic considerations. It was demonstrated, that a metastable phase formation in the quaternary material system V–Al–C–N can easily be adjusted in magnetron sputter deposition. [Copyright &y& Elsevier]

Abstract: Technological challenges in future surface engineering applications demand continuously new material solutions offering superior properties and performance. Concepts for the design of such advanced multifunctional materials can be systematically evolved and verified by means of physical vapour deposition. The classical multilayer coating concept today is well established and widely used for the design of protective thin films for wear and tribological applications. It has proven great potential for the development of novel thin film materials with tailored properties. In the past decade, the emerging new class of nanoscale coatings has offered to the material scientists an even more powerful toolbox for the engineering thin film design through a combination of the multilayer concept with new nano-coatings. Some examples are the use and integration of low friction carbon-based nanocomposites in advanced multilayer structures or the stabilization of a specific coating in another structure in a nanolaminated multilayer composite. This paper reviews the latest developments in hard, wear-resistant thin films based on the multilayer coating concept. It describes the integration of nanocrystalline, amorphous and nanocrystalline/amorphous composite materials in multilayers and covers various phenomena such as the superlattice effect, stabilization of materials in another, foreign structure, and effects related to coherent and epitaxial growth. Innovative concepts for future, smart multilayer designs based on an extremely fine structural ordering at the nanoscale are presented as well. [Copyright &y& Elsevier]

Abstract: The design and synthesis of advanced wear resistant coatings combining metallic or covalent bonded hard materials and oxide phases in a novel metastable or nanocomposite thin film structure is an emerging new field of materials research. In this paper, the phase formation, microstructure evolution and correlation between the constitution, microstructure and growth conditions of magnetron-sputtered hard Cr–Al–N–O thin films are described. The deposition experiments were carried out with a Leybold Z 550 PVD machine following a combinatorial materials science based approach for the sputtering from a segmented target, composed of bulk ceramic CrAlN and Al2O3 pieces. In each experiment, six coatings of different composition, constitution and microstructure were obtained simultaneously by placing six substrate samples in individual positions relative to the target. Both non-reactive and reactive deposition processes (in a nitrogen/argon atmosphere) were applied. No substrate bias was used and the substrate temperature was kept constant below 200 °C. The constitution, microstructure and Vickers microhardness of the coatings is discussed in dependence of their chemical composition. While non-reactive deposition processes resulted in the growth of nanocrystalline thin films of moderate hardness but brittle character, the reactive deposition led to the growth of nanocrystalline coatings with high hardness (up to 2500 HV0.05) and toughness. [Copyright &y& Elsevier]

Abstract: Thin ferromagnetic Fe–Co–Al–N films deposited by r.f. reactive magnetron sputtering were investigated with regard to the application as magnetic cores for h.f. micro-inductors. After deposition, the films were vacuum field annealed to induce a marked uniaxial anisotropy necessary for application in the gigahertz frequency range. Due to the nanocrystalline microstructure, the films exhibit good soft magnetic properties and an excellent thermal stability. The influence of the film thickness and domain structure on the high-frequency permeability and on the micro-inductor''s performance were analysed. [Copyright &y& Elsevier]

Superhard hexagonal TiB2 coatings with Vickers hardness up to 5000 HV0.015 were deposited on cemented tungsten carbide and silicon substrates by means of d.c. magnetron sputtering. Their microstructure has been studied through X-ray diffraction, X-ray reflectivity and scanning electron microscopy, in relation to the influence of substrate bias during deposition. Combined with an evaluation of mechanical properties of the deposited coatings like residual stress and Vickers hardness, the effects of plasma ion bombardment are presented and discussed. The ion impact during deposition is shown to produce structural densification and crystalline modification. A strongly (0 0 1)-ordered texture is considered as the dominant factor for hardness enhancement. [Copyright &y& Elsevier]

The synthesis of ternary metal diboride thin films as solid solution with potentially enhanced properties is recently attracting large interest. This study reports on Al-containing TiB 2 thin films grown in single-phase solid solution (Ti,Al)B 2 structure at substrate temperatures below 200 °C on cemented carbide substrates. The thin films were synthesized by non-reactive magnetron co-sputtering of a TiB 2 and an Al target. The Al content of the (Ti,Al)B 2 thin films was systematically varied between 10 and 16% metal fraction via tuning the power supplied to the Al target, while all other process parameters were kept constant. Thereby also the boron:metal ratio reduces, approaching the 2:1 stoichiometry at an Al metal-fraction of 16% (Ti 0.84 Al 0.16 B 2.00). High resolution transmission electron microscopy show that growth and microstructure is clearly impacted by the Al content and changes from (00 l) oriented growth of TiB 2.33 coatings towards various crystalline orientations of the solid solution (Ti,Al)B 2 lattice. For low Al concentration, the films exhibit moderate boron excess at grain boundaries, whereas at higher Al concentration, the (Ti,Al)B 2 thin films exhibit a microstructure with only few defects, and nearly no excess boron at boundaries (being in-line with the change in boron:metal ratio). In agreement with this observation, the Vickers microhardness of the thin films decreases slightly with increasing Al content. However, all films exhibit hardness values above 2908 HV 0.05 (30.8 GPa). • Magnetron sputtering of TiB 2 thin films with 10–16% Al (metal fraction) content • Binary TiB 2.33 reference coating • Ti 0.90 Al 0.10 B 2.22 , Ti 0.87 Al 0.13 B 2.13 , Ti 0.85 Al 0.15 B 2.04 , Ti 0.84 Al 0.16 B 2.00 films • All films grow in single-phase solid solution structure (Ti,Al)B 2 • Al content has strong impact on thin film morphology. [ABSTRACT FROM AUTHOR]