Search for dissertations about: "surface reaction"

Showing result 1 - 5 of 701 swedish dissertations containing the words surface reaction.

2. 1. Surface Chemical Characteristics of Chromium-alloyed Steel Powder and the Role of Process Parameters during Sintering

   Author : Dimitris Chasoglou; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; carbothermal reaction; sintering atmosphere; depth profiling; XPS AES; HR SEM EDX; water atomized powder; surface coverage; reduction oxidation; PM steels; sintering; Cr-Mn-spinel oxides; surface oxides;

   Abstract : Powder Metallurgy (PM) is a cost efficient method suitable for sustainable production of structural parts that have strict dimensional tolerances and complex geometries. It has been a common practice to utilize Ni and Cu as alloying elements in PM steels, but the high and fluctuating prices of Ni and the concerns around it associated with health hazards as well as the difficulty in recycling Cu lead the PM industry to search for effective alternatives such as Cr and Mn. READ MORE

4. 2. The effect of surface steps and oxides on the catalytic activity on model Pd and Rh catalysts

   Author : Chu Zhang; Synkrotronljusfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface X-ray diffraction SXRD ; X-ray photonelectron spectroscopy; Catalytic activity; Oxide; Single Crystal surface; surface structure; vicinal surface; CO oxidation; stepped surface; Fysicumarkivet A:2018:Zhang;

   Abstract : A catalyst is a substance that can speed up the rate of a chemical reaction without itself being consumed. Catalysts are crucial for chemical production industries, where about 90% of all chemicals are produced using catalysts. READ MORE

5. 3. Surface Characteristics of Water Atomized Pre-alloyed Steel Powders and their effect on Sintering

   Author : Dimitris Chasoglou; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spinel oxides; sintering; Cr-pre-alloyed powder; reduction; sintering atmosphere; surface oxide; fractography; XPS; oxidation; AES; EDX; carbothermal reaction; SEM; Powder metallurgy;

   Abstract : Powder Metallurgy (PM) is an efficient method, in terms of cost and raw material utilization, for the production of structural parts that have strict dimensional tolerances and complex geometries. In the common processing route, steel powder is fabricated by water atomization and then pressed and sintered into the final component. READ MORE

6. 4. Surface Modifications and Applications of Aqueous Silica Sols

   Author : Peter Greenwood; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; applications; Surface modification; aqueous; silica sol; silane; colloidal silica; titania;

   Abstract : Methods of modifying the surface of the particles of colloidal silica were developed and the effects of surface modification on the properties of colloidal silica were studied.Gamma-glycidoxypropyltrimethoxysilane (GPTMS) readily reacts with water to yield a hydrolysed silane that reacts readily with the silica surface. READ MORE

7. 5. Molecular beam study of non-adiabatic electron transfer in the Cl2+Ksurf surface reaction

   Author : Lars Hellberg; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; harpooning; electron transfer; Cl2; surface; exo-electrons; sticking; halogen; non-adiabatic; chemiluminescence;

   Abstract : Halogen molecules impinging on alkali metal surfaces constitute model systems for studies of charge transfer, dissociation dynamics and non-adiabatic energy dissipation in molecule-surface reactions. This thesis reports emission of exo-electrons and photons from the surface as a result of strong non-adabaticity in the Cl2 gas on K$^{solid}$ reaction. READ MORE