Sökning: "Laves-phase"

Visar resultat 1 - 5 av 17 avhandlingar innehållade ordet Laves-phase.

1. 1. Studies of inorganic crystal structures and gas adsorption process in mesoporous crystals : New approach through analysis of electron charge distribution by synchrotron powder X-ray diffraction

   Författare :Norihiro Muroyama; Osamu Terasaki; Clément Sanchez; Stockholms universitet; []
   Nyckelord :XRD; Mesoporous; Gas adsorption; Laves Phase; MEM; strukturkemi; Structural Chemistry;

   Sammanfattning : Using synchrotron powder XRD experiments, I studied (i) structures of silica mesoporous MCM-41 and MCM-48 crystals, (ii) gas adsorption processes of Ar and N2 in the mesopores of the mesoporous crystals, and (iii) bonding features of CaAl2-xZnx crystals through the analysis of electron charge density distributions. In the case of mesoporous crystals, the following two different approaches were taken depending on the number of observed X-ray reflections1. LÄS MER

3. 2. Development of a new generation of creep resistant 12% chromium steels: Microstructure of Z-phase strengthened steels

   Författare :Masoud Rashidi; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; phase transformation; CrNbN; impact toughness; Creep; CrTaN; Laves-phase; atom probe tomography; precipitation hardening; M2N; MX; transmission electron microscopy; coarsening;

   Sammanfattning : Fossil-fuel fired steam power plants provide more than 60% of the electricity generated worldwide, and account for about one third of the global CO2 emissions. Increasing the steam temperature and pressure leads to a higher thermal efficiency of the power plants and thus lower emissions. LÄS MER

4. 3. Alloys in Contact with Molten Salts for Thermal Storage Applications

   Författare :Esraa Hamdy Mohamedin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Phase transition; Molten salts; High-temperature corrosion; Alumina-forming alloys; Carburisation; Thermal energy storage TES ; Laves phase; Concentrated solar power CSP ;

   Sammanfattning : The combination of a concentrated solar power (CSP) plant and a thermal energy storage (TES) system is a promising technology for power generation, in that it overcomes the challenges commonly faced by renewable energy systems, such as intermittency, dispatchability, and the gap between the energy supply and energy demand. The third generation (Gen3) CSP plants are designed to increase plant efficiency by using supercritical carbon dioxide (sCO2) instead of steam for the Brayton cycle gas turbines, requiring a minimum operating temperature of 750°C for the TES materials. LÄS MER

5. 4. Precipitation Reactions at High Temperatures in 9-12% Chromium Steels

   Författare :Mats Hättestrand; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermo-dynamical simulations; creep resistant; 9-12% chromium steel; energy filtered TEM; precipitates; atom probe field ion microscopy; quantitative metallography;

   Sammanfattning : This thesis reports on quantitative investigations of microstructural changes, mainly precipitation reactions, occurring during heat treatment, ageing and creep of 9-12% chromium steels. Several alloys with varying composition have been investigated. LÄS MER

7. 5. Structure and Stability of Bi1-xSbx and CaAl2-xZnx

   Författare :Karin Söderberg; Osamu Terasaki; Tetsu Ohsuna; Masaki Takata; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inorganic chemistry; Oorganisk kemi;

   Sammanfattning : This thesis is focused on two intermetallic systems Bi1-xSbx and CaAl2-xZnx. Bi and Sb transform into a peculiar incommensurate composite structure under pressure and our intention was to examine the structure and how alloying influences this incommensurate structure. LÄS MER