Sökning: ".alpha.-Al2O3"

Hittade 4 avhandlingar innehållade ordet .alpha.-Al2O3.

  1. 1. The microstructure and stability of CVD aluminia coatings

    Författare :Mats Halvarsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; .kappa.-Al2O3; SEM; multilayers; TEM; .alpha.-Al2O3; phase transformation; CVD; XRD; microstructure;

    Sammanfattning : This thesis has examined topics of relevance for increasing the understanding of alumina coatings produced by Chemical Vapour Deposition. The work consists of three parts: (i) The microstructure of Al2O3 coatings; (ii) the .kappa.-Al2O3 -> . LÄS MER

  3. 2. Emerging mechanisms of FeCrAl(RE) oxide scale formation and permeation from 1st principles

    Författare :Vedad Babic; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Alumina forming alloys are important for high temperature applications due to the high stability of the alpha-Al2O3 scale which forms above 900 C. FeCrAl(RE) alloys are alumina formers with small additions of reactive elements, RE e.g. Y, Zr, Hf and Ce, added to improve among others oxidation behavior and scale adhesion. LÄS MER

  4. 3. Catalyst Deactivation by Coke Formation in Acetylene Hydrogenation

    Författare :Staffan Asplund; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; preparative liquid chromatography; gross error detection; acetylene hydrogenation; coke deposition; coke formation; catalyst deactivation;

    Sammanfattning : Several aspects of catalyst deactivation have been studied with reference toselective acetylene hydrogenation, a reaction used industrially to purify ethylene from unwanted acetylene. A mathematical model has been developed for an industrial packed-bed reactor, employing a supported Pd catalyst. LÄS MER

  5. 4. Surface studies on α–sapphire for potential use in GaN epitaxial growth

    Författare :Björn Agnarsson; Mats Göthelid; Anders Sandell; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Surfaces and interfaces; Ytor och mellanytor;

    Sammanfattning : This Licentiate thesis summarizes the work carried out by the author the years 2004 to 2008 at the University of Iceland and the Royal Institute of Technology (KTH) in Sweden. The aim of the project was to investigate the structure of sapphire (alpha-Al2O3) surfaces, both for pure scientific reasons and also for potential use as substrate for GaN-growth by molecular beam epitaxy. LÄS MER