Search results for "Metallurgy"

Friction based Solid State Welding Techniques for Transportation Industry Applications

2014

Abstract Solid bonding based processes represent an effective solution in terms of both joints mechanical performances and sustainability. In the last years, both the academic and the industrial researchers focused their work on two solid-state processes: Friction Stir Welding (FSW) and Linear Friction Welding (LFW). The former, patented in 1991 by TWI, is used to weld sheet metal in different joint morphologies, i.e. butt, lap T and 3D joints. The latter has been known for several years, but a growing interest is observed in the last years due to the enhancement of the welding machines performances. LFW, used to join bulk components, is particularly suited for aeronautical and aerospace ap…

Effect of diamond microdermabrasion on oily skin: a case report

2018

Background: The history of microdermabrasion dates back to ancient Egypt. The first treatment in Europe occurred in 1985 and has since become a popular method of exfoliation of the superficial layers of skin. Microdermabrasion is an effective method of taking care of the skin of the face and body, bringing about immediate effects in the treatment of deep scars and stretch marks. Aim of the study: To determine the effectiveness of diamond microdermabrasion on a person with hyperuricemia of the sebaceous glands. Materials and methods: Based on interviews, a case analysis, and the impact of diamond microdermabrasion on the structure of the skin’s surface, the level of hydration, oiliness and e…

Opportunity of metallic interconnects for ITSOFC : Reactivity and electrical property.

2006

International audience; Iron-base alloys (Fe-Cr) are proposed hereafter as materials for interconnect of planar-type intermediate temperature solid oxide fuel cell (ITSOFC); they are an alternative solution instead of the use of ceramic interconnects. These steels form an oxide layer (chrornia) which protects the interconnect from the exterior environment, but is an electrical insulator. One solution envisaged in this work is the deposition of a reactive element oxide coating, that slows down the formation of the oxide layer and that increases its electric conductivity. The oxide layer, formed at high temperature on the uncoated alloys, is mainly composed of chromia; it grows in accordance …

Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials

2013

Author's version of an article in the journal: Journal of Electronic Materials. Also available from the publisher at: http://dx.doi.org/10.1007/s11664-013-2917-0 Thermoelectric materials, for example skutterudites and magnesium silicides, are being investigated as promising materials for medium-to-high-temperature waste heat recovery in transport and in industry. A crucial aspect of the success of a thermoelectric material is its stability over time when exposed to rapid heating and cooling. In this work different aspects of the degradation of these thermoelectric materials at high temperature were examined. Initial thermal durability was studied, and several candidate coatings were evaluat…

Thermal atomic layer deposition of AlOxNy thin films for surface passivation of nano-textured flexible silicon

2019

Abstract Aluminum oxynitride (AlOxNy) films with different nitrogen concentration are prepared by thermal atomic layer deposition (ALD) for flexible nano-textured silicon (NT-Si) surface passivation. The AlOxNy films are shown to exhibit a homogeneous nitrogen-doping profile and the presence of an adequate amount of hydrogen, which is investigated by Time-of-Fight Elastic Recoil Detection Analysis (ToF-ERDA). The effective minority carrier lifetimes are measured after the NT-Si surface passivation; the minimum surface recombination velocity (SRV) of 5 cm-s−1 is achieved with the AlOxNy film in comparison to the Al2O3 and AlN films (SRV of 7–9 cm-s−1). The better SRV with AlOxNy film is due …

Structural organization of silanol and silicon hydride groups in the amorphous silicon dioxide network

2011

We present a study on the effects of an isothermal annealing treatment on a-SiO 2 having a significant content of silanol hydride groups (Si-H). We examined the properties of the IR absorption bands of silanol (Si-OH) and silicon hydride groups as a function of the duration of the thermal treatment. We showed that the Si-OH and Si-H groups contents decrease in a linearly correlated way. The annealing dynamics suggest that the two species are close to each other in the amorphous network. We showed that the profile of the silanol groups absorption band is the same as that observed in other commercial a-SiO 2 materials, irrespectively of the concomitant presence of nearby Si-H groups, and, mor…

Variation of lattice constant and cluster formation in GaAsBi

2013

We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220–315 C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out o…

Atomic layer deposition of LixTiyOz thin films

2013

Atomic layer deposition (ALD) was employed to deposit ternary films of LixTiyOz. The film growth at a deposition temperature of 225 °C was studied using both titanium tetra-isoropoxide (Ti(OiPr)4) and titanium tetrachloride (TiCl4) as titanium precursors. Lithium tert-butoxide (LiOtBu) was applied as the lithium source and water was used as the oxygen source for all metal precursors. The type of titanium precursor chosen strongly affected film growth: with TiCl4 the resulting LixTiyOz films were highly air-sensitive and the lithium concentration was low, whereas with Ti(OiPr)4 the films were relatively stable in air and with a lithium content which was easily controlled over a wide range. F…

AlN Ceramics from Nanosized Plasma Processed Powder, its Properties and Application

2014

Bioaccessibility of minerals in school meals: Comparison between dialysis and solubility methods

2005

Abstract Determinations have been made of content and bioaccessibility of Ca, Fe, Zn and Cu in 13 dishes collected from a catering service delivering to a school. Bioaccessibility was estimated by measuring the soluble or dialyzable mineral fraction resulting from in vitro gastrointestinal digestion of the meal. The analyzed dishes had mineral contents (μg/g) in the following ranges: Ca (74.1–913), Fe (2.8–17.9), Zn (2.8–13.1), Cu (0.28–1.90). Mineral solubility and dialysis percentages were as follows: Ca (1.7–96.2; 0.75–61.3), Fe (16.0–97.8; 0.23–19.0), Zn (22.6–93; 5.78–31.45), Cu (35.7–92.3; 0.66–25.0). The highest bioaccessible Ca content corresponded to fish-based dishes, while vegeta…