Yves Wouters

Bio: Yves Wouters is an academic researcher from University of Grenoble. The author has contributed to research in topics: Oxide & Chromia. The author has an hindex of 25, co-authored 134 publications receiving 1951 citations. Previous affiliations of Yves Wouters include Saint-Gobain & Grenoble Institute of Technology.

The Kinetic Behaviour of Metals in Water Vapour at High Temperatures: Can General Rules Be Proposed?

Abstract: The thermal oxidation of metals by water vapour and by oxygen is compared and several ideas are advanced to explain the differences often observed. The incorporation of hydroxyl ions in the oxide is shown to be of importance, but possible only if vacancy or interstitial oxide defects are present. The decomposition rate of H 2 O is another key-point and is shown to be correlated with the surface acidity of the oxide. Non-acidic p-type oxides could be very passive in water vapour whereas more acidic n-type oxides may oxidize at the same rate in both atmospheres or even more rapidly provided that rapid OH transport can take place within the formed scales.

Characterization of Chromia Scales Grown on Pure Chromium in Different Oxidizing Atmospheres

Abstract: Scanning electron microscopy, X-ray diffraction, photoelectrochemistry and microphotoelectrochemistry have been used to characterize thin chromia scales, in the micrometer range, grown on pure chromium at 900°C in oxygen and in water vapour. The duplex structure formed, more easily observable in water vapour grows by the opposite transport of chromium and of oxide/hydroxide ions. The external chromia subscale exhibits the usually reported 3.5 eV bandgap whereas the internal subscale presents a reduced gap possibly due to impurity contribution. Imaging the photocurrent generated in this subscale allows the observation of good metal-oxide interface properties of samples grown in H2O, whereas samples grown in O2, (liable to cracking during cooling), exhibit partially disrupted zones.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Efficient photochemical water splitting by a chemically modified n-TiO2.

Abstract: Although n-type titanium dioxide (TiO2) is a promising substrate for photogeneration of hydrogen from water, most attempts at doping this material so that it absorbs light in the visible region of the solar spectrum have met with limited success. We synthesized a chemically modified n-type TiO2 by controlled combustion of Ti metal in a natural gas flame. This material, in which carbon substitutes for some of the lattice oxygen atoms, absorbs light at wavelengths below 535 nanometers and has a lower band-gap energy than rutile (2.32 versus 3.00 electron volts). At an applied potential of 0.3 volt, chemically modified n-type TiO2 performs water splitting with a total conversion efficiency of 11% and a maximum photoconversion efficiency of 8.35% when illuminated at 40 milliwatts per square centimeter. The latter value compares favorably with a maximum photoconversion efficiency of 1% for n-type TiO2 biased at 0.6 volt.

The Oxidation of Metals

Abstract: Oxidation of Metals and Alloys By Dr. O. Kubaschewski and B. E. Hopkins. Pp. xv + 239. (London: Butterworths Scientific Publications, Ltd.; New York: Academic Press, Inc., 1953.) 35s. net.