ASM International

Thursday, November 15, 2007

CSUN Student Night

Growth of (La,Sr)MnO₃ Thin Films - Cathode Material in Solid Oxide Fuel Cells - Shaahin Jahangard

LaMnO₃ and SrMnO₃ films of two different thicknesses were grown on SrTiO₃(100) and MgO(100) substrates using Pulsed laser deposition (PLD). The thickness and growth rate of these films was determined using X-Ray Reflectometry (XRR). Atomic Force Microscopy (AFM) was used to characterize their surface morphology. Determining the growth rates of LaMnO₃ and SrMnO₃ helps bypass making a new target for each particular composition of (La,Sr)MnO₃ and saves time. The growth rate of LaMnO₃ was found to be 0.107Ǻ/Pulse. The growth rate of SrMnO₃, however, could not be determined because of its density match with the SrTiO₃ substrate. The AFM scans of the LaMnO₃ films on SrTiO₃(100) also revealed a very flat morphology with an rms roughness of roughly 3 Angstroms. The attainment of thin, flat films with a well characterized thickness is necessary for the oxygen uptake studies.

 

Novel Configuration of Diamond Polishing for the Fabrication of Micromachining Tools - Philip Edward Salazar

Advancements in micromachining are changing the technological world by decreasing dimensions of tiny components. This research addressed the configuration of a diamond polishing process and compared how different polishing conditions affect the outcome and integrity of the fabrication of a diamond micro-tool. The following input parameters studied were the abrasive grain size used for grinding and polishing (diamond particles sizes ranged from 0-2μm, 5-10μm, and 20-40μm) and the polishing direction of the diamond. The response parameters studied were the polished surface roughness, topography, and the forces acting on the diamonds during the experimental process. Results indicate that for the simple motion case, as the diamond particle size increased, so did the roughness. The 5-10mm particles in the complex motion case yielded the best surface finish with an average surface roughness Ra value of 13.88mm. The experiment which yielded the worst surface roughness was during the simple motion, 20-40mm case that resulted in an average surface roughness Ra value of 25.20mm.