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Recently, there has been increasing interest in the use of hot targets to enhance the sputter deposition of materials. However, the actual temperature of the target surface is normally not known. In this work, we directly measured the radial distribution of the surface temperature of a MAK 2 in. Ti water-cooled target using a type K thermocouple during the operation of the sputtering system. Principally, the measurements were made as a function of applied DC power and argon gas pressure. Given the importance of chemical reactions between the gas and the target during reactive sputtering, we have also measured the target temperature as a function of the nitrogen concentration in an argon-nitrogen gas mixture. A few of the reactively sputtered samples were analyzed by x-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Titanium‐Tantalum coatings are deposited by magnetron co‐sputtering technique, using independently driven titanium and tantalum targets. The effect of the Ta content on the structure, mechanical, and wear properties of Ti films is investigated. It is found that the percentage of the added Ta varies linearly from 3.7 to 31.3 at% by increasing the power applied to the Ta target from 10 to 100 W. The XRD results show that the coatings are crystalline, and there is no evidence of the formation of intermetallic phases, instead formation of metastable phases of α″ and β depending on Ta content are observed, though the samples are deposited at low temperature (150 °C). It is shown that the elastic strain to failure (H/Er; hardness to reduced elastic moduli ratio) can be increased by 40% through the formation of crystalline phases with a lower E, while the hardness remains constant. The tribological study shows that increasing the Ta content up to 14.9 at% causes a significant improvement in adhesion of the coating to a soft metallic substrate. [ABSTRACT FROM AUTHOR]

There are many polymorphs of Nb2O5, each with interesting properties that have been explored for biomedical, photocatalytic, and optical applications. However, Nb2O5 is not generally used for mechanical applications owing to its low hardness (8GPa). The objective of this work was to evaluate the effects resulting from the addition of silicon (Si) into the Nb2O5 structure, with the aim of increasing its hardness through the formation of a nanostructured composite coating. In this paper, the authors report the structure and mechanical properties of Nb2O5 as a function of the silicon content (0-5.5 at. %). The coatings were deposited on silicon and D2 steel substrates using a confocal-dual magnetron sputtering system using a mixture of argon and oxygen (80:20) with each magnetron (Nb and Si targets) independently driven. The coatings were annealed at 550°C to obtain a crystalline structure. However, analysis of the optical properties indicated the persistence of a substoichiometric amorphous phase. Despite the contribution of the amorphous phase, the mechanical-tribological properties were slightly improved after Si incorporation. The hardness reached a maximum of 17.6GPa for the samples deposited at 50W in the Si target, coupled with a reduction in both the coefficients of friction and wear. [ABSTRACT FROM AUTHOR]

In this paper, we report the stabilization of the δ-phase of Bi2O3 thin films from room temperature (RT) to 500°C by the addition of tantalum ions. The δ-Bi2O3 phase is the material presenting the highest ionic conductivity; as bulk it is stable in a reduced temperature range from 730 to 825°C, while the α-phase is the RT stable phase. However, when produced by atomic aggregation methods as a nanometric thin film, the delta-phase can be maintained at atmospheric conditions and it actually reverts to the alpha-phase only after thermal annealing, such transformation usually occurs around 250–350°Cby passing through the β-phase. In this work, we report that tantalum addition during the deposition of the Bi2O3 films by magnetron sputtering allows the maintenance of the delta phase up to 500°C upon thermal annealing in air. [ABSTRACT FROM AUTHOR]