Synthesis of Cobalt-Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes.

To obtain highly homogeneous cobalt-nickel aluminate spinels with small crystallite sizes, CoNiAl alloy thin films were primarily deposited using Laser-induced Thermionic Vacuum Arc (LTVA) as a versatile method for performing processing of multiple materials, such as alloy/composite thin films, at a nanometric scale. Following thermal annealing in air, the CoNiAl metallic thin films were transformed into ceramic oxidic (Co,Ni)Al2O4 with controlled composition and crystallinity suitable for thermal stability and chemical resistance devices. Structural analysis revealed the formation of (Co,Ni)Al2O4 from the amorphous CoNiAl alloys. The mean crystallite size of the spinels was around 15 nm. Thermal annealing induces a densification process, increasing the film thickness together with the migration process of the aluminum toward the surface of the samples. The sheet resistance changed drastically from 200-240 Ω/sq to more than 106 Ω/sq, revealing a step-by-step conversion of the metallic character of the thin film to a dielectric oxidic structure. These cermet materials can be used as inert anodes for the solid oxide fuel cells (SOFCs), which require not only high stability with respect to oxidizing gases such as oxygen, but also good electrical conductivity. These combination metal-ceramics are known as bi-layer anodes. By controlling the crystallite size and the interplay between the oxide/metal composite, a balance between stability and electrical conductivity can be achieved.

Characterization of Platinum-Based Thin Films Deposited by Thermionic Vacuum Arc (TVA) Method.

The current work aimed to characterize the morphology, chemical, and mechanical properties of Pt and PtTi thin films deposited via thermionic vacuum arc (TVA) method on glass and silicon substrates. The deposited thin films were characterized by means of a scanning electron microscope technique (SEM). The quantitative elemental microanalysis was done using energy-dispersive X-ray spectroscopy (EDS). The tribological properties were studied by a ball-on-disc tribometer, and the mechanical properties were measured using nanoindentation tests. The roughness, as well as the micro and nanoscale features, were characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The wettability of the deposited Pt and PtTi thin films was investigated by the surface free energy evaluation (SFE) method. The purpose of our study was to prove the potential applications of Pt-based thin films in fields, such as nanoelectronics, fuel cells, medicine, and materials science.

Synthesis and Characterization of Complex Nanostructured Thin Films Based on Titanium for Industrial Applications.

Titanium-based composites-titanium and silver (TiAg) and titanium and carbon (TiC)-were synthesized by the Thermionic Vacuum Arc (TVA) method on substrates especially for gear wheels and camshaft coating as mechanical components of irrigation pumps. The films were characterized by surface morphology, microstructure, and roughness through X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Small-Angle Neutron Scattering (SANS). The silver (Ag) films crystallized into a cubic system with lattice a = 4.0833 Å at room temperature, indexed as cubic Ag group Fm3m. The crystallites were oriented in the [111] direction, and mean grain size was 111 = 265 Å. The TiC structure revealed a predominant cubic TiC phase, with a = 0.4098 as a lattice parameter determined by Cohen's method. Average roughness (Ra) was 8 nm for the as-grown 170 nm thick TiAg film, and 1.8 nm for the as-grown 120 nm thick TiC film. Characteristic SANS contribution was detected from the TiAg layer deposited on a substrate of high-quality stainless steel with 0.45% carbon (OLC45) in the range of 0.015 Å-1 ≤ Q ≤ 0.4 Å-1, revealing the presence of sharp surfaces and an averaged triaxial ellipsoidal core-shell object.