The metastable, glasslike solid-state phase of HAlO and its transformation to Al/Al2O3 using a CO2 laser

Veith Michael, Andres Kathrin, Faber Stefan, Blin Joël, Zimmer Michael, Wolf Yan, Schnöckel Hansgeorg, Köppe Ralf, De Masi Remo, Hüfner Stefan. 2003. The metastable, glasslike solid-state phase of HAlO and its transformation to Al/Al2O3 using a CO2 laser. European Journal of Inorganic Chemistry (24) : 4387-4393.

Résumé : Bis(tert-butoxyaluminum dihydride) (tBuOAlH2)2 decomposes on metal surfaces heated to 250 C (Fe, Ni, Cu, Pt) and under reduced pressures of 0.01 0.1 atm with elimination of dihydrogen and isobutene to form a glasslike, amorphous film, which is composed of equimolar parts of hydrogen, aluminum and oxygen (elemental analysis, EDX analysis). The gases eliminated during this process were characterized by mass spectroscopy (H2, isobutene) or by infrared matrix techniques (isobutene). The exclusive binding of hydrogen to aluminum is deduced from IR spectroscopy of the HAlO film and of its deuterated form DAlO. The HAlO layer (which shows no X-ray diffraction pattern), when heated to 450 C or when exposed to a CO2 laser, loses hydrogen and transforms to an almost stoichiometric composite with nanoscale crystalline aluminum and aluminum oxide (Al/Al2O3) as ingredients. This transformation may be followed by IR spectroscopy, by 27Al MAS NMR or by XPS, the latter showing different signals (Al, 2p electrons, Mg-K[alpha], [thêta] = 0 °) for HAlO (74.2 eV) and for the composite (Al: 72.1 eV, Al2O3: 75.3 eV). Microstructures that are characterized by different chemical compositions and different optical contrasts of the ''drawing'', relative to the surrounding matrix, may be generated with an X/Y-table and a CO2 laser.

Classification Agris : 000 - Autres thèmes
K50 - Technologie des produits forestiers

Auteurs et affiliations

• Veith Michael, Universität des Saarlandes (DEU)
• Andres Kathrin, Universität des Saarlandes (DEU)
• Faber Stefan, Universität des Saarlandes (DEU)
• Blin Joël, CIRAD-FORET-BOIS (FRA) ORCID: 0000-0001-6715-2453
• Zimmer Michael, Universität des Saarlandes (DEU)
• Wolf Yan, Universität des Saarlandes (DEU)
• Schnöckel Hansgeorg, Universität Karlsruhe (DEU)
• Köppe Ralf, Universität Karlsruhe (DEU)
• De Masi Remo, Universität des Saarlandes (DEU)
• Hüfner Stefan, Universität des Saarlandes (DEU)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/561647/)

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