Francis Maury

Bio: Francis Maury is an academic researcher from University of Toulouse. The author has contributed to research in topics: Chemical vapor deposition & Thin film. The author has an hindex of 28, co-authored 194 publications receiving 2621 citations. Previous affiliations of Francis Maury include Centre national de la recherche scientifique & National Polytechnic Institute of Toulouse.

Anisotropy of defect creation in electron-irradiated iron crystals

Abstract: Single crystals of \ensuremath{\alpha}-iron were irradiated perpendicularly to the (100), (110), and (111) planes with electrons in the range 0.35-1.7 MeV and their electrical resistivity change rates were measured. A geometrical model of the threshold-energy surface for atomic displacement in a bcc lattice produces a fit to the experimental data leading to the following values for the threshold energies in the principal crystal directions: ${T}_{d}^{〈100〉}=17\ifmmode\pm\else\textpm\fi{}1$ eV, ${T}_{d}^{〈111〉}=20\ifmmode\pm\else\textpm\fi{}1.5$ eV, and ${T}_{d}^{〈110〉}\ensuremath{\gtrsim}30$ eV. The specific resistivity of a Frenkel pair is deduced to $\ensuremath{\rho}_{F}^{\mathrm{Fe}}=(30\ifmmode\pm\else\textpm\fi{}5)$ \ensuremath{\mu}\ensuremath{\Omega}cm/at.%. From the obtained ${T}_{d}'\mathrm{s}$ we derived an interatomic potential of the Born-Mayer type, valid in the range $1.2\ensuremath{\le}r\ensuremath{\le}2.5$ \AA{}. We propose as a good choice: $V(r)=8900{e}^{\ensuremath{-}4.5r}$ eV. The recovery due to isochronal annealing during stage I, after irradiation at different electron energies, was measured and related to specific recovery mechanisms. Thus, the first important substage, ${I}_{B}$ (\ensuremath{\sim} 66 K), is due to the recovery of close Frenkel pairs created in the $〈100〉$ direction, while a comparison of calculated cross sections suggests that ${I}_{C}$ (\ensuremath{\sim} 87 K) possibly stems from $〈111〉$ close pairs. Substage ${I}_{D}$ (90-110 K) is complex; its first part, below 100 K, originates mostly from defects produced in the $〈100〉$ direction and the second part, above 100 K, together with ${I}_{E}$, principally originates from defects produced in the $〈111〉$ direction.

Copper precipitation in FeCu, FeCuMn, and FeCuNi dilute alloys followed by X-ray absorption spectroscopy

Abstract: Samples of FeCu, FeCuMn, FeCuNi, and FeCuCr alloys containing 1.5 wt% of each solute have been electron irradiated around 290 degrees C or thermally aged at 500 degrees C for various times. It is known that such treatments induce Cu precipitation; the Cu depletion of the matrix is measured by the resistivity decrease of the samples. The crystallographic environment of the solute atoms in the irradiated or aged samples has been studied by XAS (X-ray absorption spectroscopy). The data show that Cr, Mn, and Ni atoms mainly remain in BCC solid solution during the Cu precipitation. The first Cu precipitates are found to be of BCC structure, i.e. coherent with the matrix. At the longest ageing times, they have become of FCC structure. In the electron-irradiated samples, the data show that, up to a fluence of 5 C cm-2, most of the Cu precipitates (>80%) are still of BCC structure. The fraction of BCC precipitates has been estimated from both the X-ray-absorption near-edge structure (XANES) and extended X-ray-absorption fine-structure (EXAFS) data. It appears that, for both FeCu and FeCuMn samples, similarly aged, the FCC fraction is larger in cold-rolled samples than in pre-annealed and quenched ones. The results obtained are consistent, in the FeCu case, with a simple linear correspondence between fluence and time, 1 C cm-2 at 300 degrees C being equivalent to approximately 10 h at 500 degrees C. The Cu precipitation is found to be accelerated, at least in its first stages, by the presence of Mn in the alloy.

A review of additive manufacturing of ceramics by powder bed selective laser processing (sintering / melting): Calcium phosphate, silicon carbide, zirconia, alumina, and their composites

Abstract: This review offers an overview on the latest advances in the powder bed selective laser processing, known as selective laser sintering/melting, of calcium phosphate, silicon carbide, zirconia, alumina, and some of their composites. A number of published studies between 1991 and August 2020 was collected, analyzed and an inclusive state of the art was created for this review. The paper focuses on the process description, feedstock criteria and process parameters and strategy. A comparison is made between direct and indirect powder bed selective laser processing of each ceramic, regarding the present achievements, limitations and solutions. In addition, technical aspects and challenges about how to address these issues are presented.

A review on the visible light active titanium dioxide photocatalysts for environmental applications

Abstract: Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

Handbook of Chemistry and Physics

Abstract: There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate