Sökning: "transition-metal carbides"

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden transition-metal carbides.

1. 1. Atomistic simulation and experimental studies of transition metal systems involving carbon and nitrogen

   Författare :Jiaying Xie; Seshadri Seetharaman; Oleg Ostrovski; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transition metal carbides; Transition metal nitrides; Transition metal carbo-nitrides; Lattice inversion method; Interatomic potential; Atomistic simulation; Metallurgical process engineering; Metallurgisk processteknik;

   Sammanfattning : The present work was initiated to investigate the stability, structural and thermodynamic properties of transition metal carbides, nitrides and carbo-nitrides by atomistic simulations and experimentations. The interatomic pair potentials of Cr-Cr, Mn-Mn, Fe-Fe, C-C, Cr-C, Mn-C, Fe-C, Cr-Fe, Cr-N and Mn-N were inverted by the lattice inversion method and ab initio cohesive energies, and then employed to investigate the properties of Cr-, Mn- and Fe-carbides by atomistic simulations in this work. LÄS MER

3. 2. Thermodynamic investigations of transition metal systems containing coabon and nitrogen

   Författare :Lidong Teng; Seshadri Seetharaman; Tooru Matsumiya; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; thermodynamic activity; galvanic cell technique; transition metal carbides; transition metal nitrides; phase equilibrium; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Sammanfattning : In view of the important applications of carbides and carbo-nitrides of transition metals in the heat-resistant and hard materials industries, the thermodynamic activities of Cr and Mn in the Cr-C, Fe-Cr-C, Mn-Ni-C and Mn-Ni-C-N systems have been studied in the present work by the use of the galvanic cell technique. CaF2single crystals were used as the solid electrolyte. LÄS MER

4. 3. Reactivity of Transition-Metal Compounds from Electronic Structure

   Författare :Aleksandra Vojvodic; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; magnetic edge states; electronic structure; density-functional theory; growth; surface states and resonances; nitrides; density of states; hydrodesulphurisation; sulphides; steam reforming; transition-metal carbides; Bronsted-Evans Polanyi relation; scaling relations; adsorption; descriptor; reactivity; catalysis;

   Sammanfattning : Transition-metal carbides (TMC's), nitrides, and sulfides belong to the class of materials known as transition-metal compounds (TMX's). Besides having intriguing properties, these materials are relevant for, e.g., growth and catalysis. LÄS MER

5. 4. Microstructure aspects of transition metal carbide thin films

   Författare :Jun Lu; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; vapour deposition; transition metal carbide; nanocrystallinity; epitaxy; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

   Sammanfattning : Transition metal carbides are important refractory materials used in many thin film applications. In this thesis, several transition metal carbides have been deposited using different chemical vapour deposition (CVD) and evaporation processes. In particular, the phase composition and microstructure of these carbide films have been studied. LÄS MER

7. 5. A Theoretical Perspective on the Chemical Bonding and Structure of Transition Metal Carbides and Multilayers

   Författare :Mikael Råsander; Olle Eriksson; Biplab Sanyal; Risto Nieminen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electronic structure; transition metal carbides; density functional theory; disorder; multilayers; chemical bonding; materials science; Condensed matter physics; Kondenserade materiens fysik; Materialvetenskap; Materials Science;

   Sammanfattning : The present thesis deals with a theoretical description of issues regarding chemical bonding, structure and stability of transition metal carbides and multilayered structures. First principles density functional theory has been used extensively to investigate the properties of alloyed solutions of transition metal carbides. LÄS MER