Undergraduate senior projects are part of the core program of the department, and Kaplan’s group offers new topics each year. The currently available projects are listed below. If you are interested, please contact Prof. Kaplan by e-mail.
The Influence of Nitrogen on Sintering and Grain Growth in Alumina
It is the hypothesis of this study that nitrogen adsorbs to surfaces of alumina (a-Al2O3), reducing the surface energy and thus reducing the driving force for densification during sintering. In a similar manner, nitrogen adsorption may affect the mobility of grain boundaries, thus influencing the kinetics of grain growth.
The project will have two experimental parts. In the first, the students will learn to prepare their own alumina compacts using powder processing technology. Sintering will be conducted in nitrogen, and the density as a function of annealing time will be compared to samples sintered in helium and in air. In the second part, fully sintered alumina samples will be annealed in nitrogen or in helium, and the grain size as a function of annealing time measured from SEM micrographs, and the grain boundary mobility will be determined.
Surface Modification During TEM Sample Preparation
The goal of this project is to understand the surface roughness due to the various stages of TEM specimen preparation. TEM specimens will be prepared from aluminum and alumina, using mechanical polishing and ion milling. The surface morphology will then be characterized using combined AFM and SEM, to understand the influence of various stages of the TEM specimen preparation methods on the microstructure of the surface.
ZAF Calculations for Quantitative EDS
The goal of this project is to develop a stand-alone ZAF calculation for quantitative EDS analysis. Once the code is written, stoichiometric standards will be characterized using EDS, and their apparent concentration determined from the EDS signals. The apparent concentration versus real concentration will be compared as a function of EDS acquisition conditions.
Two-Step Sintering of Alumina
Two-step sintering of ceramics is a novel method of reaching full density with a minimal grain size. In this method, particle necking is first rapidly achieved at an elevated temperature, and then the sample is sintered at a lower temperature where grain boundary diffusion is maximized and grain boundary mobility is minimized. This project will experimentally determined the optimized temperatures for two-step sintering of alumina doped with MgO. The students will learn to prepare their own alumina compacts using powder processing technology. After sintering the samples will be characterized by means of density (Archimedes method) and grain size (using SEM micrographs from polished cross sections).
The Mobility of Grain Boundaries as a Function of Solute Drag in Alumina
In this project, sintered polycrystalline alumina which had been doped with Fe2O3 or Cr2O3 will be annealed, and the grain size will be determined as a function of annealing time by SEM. From the grain size measurements, the grain boundary mobility will be determined, and the influence of Fe and Cr on mobility via solute drag will be determined. The students will prepare the doped alumina compacts using powder processing technology. After sintering the samples will be prepared for SEM (cutting, polishing, thermal etching), and the grain size will be measured from SEM micrographs.
The Solubility Limit of Fe in Al2O3
It is known that key dopants and impurities in alumina can significantly influence the densification process during sintering, or grain growth kinetics. However, the high temperature solubility limits of dopants in alumina have rarely been quantitatively determined. In this project, polycrystalline alumina which was saturated with Fe at high temperatures will be quenched to room temperature. Saturation will be confirmed by XRD to see that a two-phase microstructure exists. The amount of Fe in solution, which is the solubility limit for saturated samples, will be determined from fully quantitative WDS measurements.
The students will prepare the doped alumina compacts using powder processing technology. After sintering the students will prepare the samples for XRD and SEM(WDS) characterization (cutting and polishing).