Beryllium Oxide is a ceramic material most notably used in the electronics industry due to its outstanding thermal conductivity. Because of this property it is also of interest for use as an insulator under high density plasma exposure. Post exposure the beryllium samples undergo a very specific series of characterization steps. Samples are subject to optical microscopy, in an attempt to identify noticeable surface changes when compared to a control sample. Specific spots show maximum exposure, and are further investigated via XPS. X-ray Photoelectron Spectroscopy shows chemical changes in regions of maximum exposure. Specific depth profiling is utilized to identify possible Deuterium migration, lanthanide exposure, and oxidation effects. XPS is critical for providing detail of the depth of deuterium exposure throughout the material, along with possible deuterium implantation within the crystal lattice of the existing beryllium oxide. X-ray Diffraction comparison between irradiated and control samples shows lattice expansion and residual strain throughout the material. This is a crucial discovery when comparing the impact of the residual strain to the maximum tensile stress. Peak broadening shown on the 2ϴ XRD plot identifies the extent of intergranular strain left by possible deuterium implantation into the beryllium oxide crystal lattice identified through XPS. Thermal conductivity of irradiated samples is tested to ensure that the most redeeming quality of the material is consistent post exposure.

The thermoacoustic effect provides many benefits compared to current cooling methods. The process can achieve stable and reliable cooling without the use of refrigerants or environmentally hazardous chemicals. Strontium Barium Niobate (SBN) is a relaxer ferroelectric ceramic material that exhibits piezoelectric properties due to its tetragonal tungsten-bronze crystal structure.  A piezoelectric is a material that when subjected to mechanical deformation, undergoes polarization which creates electricity and vice verse.  The purpose of this project was to identify piezoelectric properties of SBN, and utilize an SBN piezo crystal for fine-tuned sound generation in a thermoacoustic cooler. In order to achieve this, understanding the physical phenomena behind thermoacoustic cooling and building a prototype thermoacoustic cooler were first accomplished. From there, identifying the piezoelectric characteristics of SBN and construction of a miniaturized model was initiated. Comparisons were made between the macroscopic and miniature models to determine device properties and characteristics. Device miniaturization reveals a variety of challenges that were previously unobserved in the macroscopic device. A cooling effect was observed and a temperature gradient was achieved in both the macroscopic and miniaturized prototypes. However, the efficiency factor of the micro device was highly correlated to the device geometry and construction. Ultimately, the goal of this project was to achieve thermoacoustic cooling on the micro scale which can only be achieved by understanding the nanostructure and the relationship between grain size and domain polarization mechanisms. Piezoelectrics provide an excellent avenue to achieve this goal due to their high overall efficiency of converting lattice distortions into electrical energy, high curie temperature, their idealized frequency response time and their relative environmental stability.

This report summarizes a method for constructing a Seebeck coefficient tester, the basics behind its operation as well as analyzation of SrxBa1-xNb2O6. Thermoelectric oxides have a very promising and bright future for waste heat recovery, and it is the aim of this project to learn more about them and develop some new materials. The goal of this project is to be able to analyze the Seebeck coefficient of materials at very high temperatures. Current technology is only around 1000 K, and the goal of this project is to be able to measure the Seebeck coefficient of materials to be around 1300 C. The tester is being constructed using our own designs, and a LabView program was created to enable the measurement and operation of the instrument. The setup is fairly straightforward using a 4 point probe test to measure the voltage and temperature difference. For these tests we are using R-type thermocouples instead of the usual K-type thermocouples, as it can handle the very high temperature that is desired. Through developement of a high temperature Seebeck tester there will be greater possibilities in the future for use of various thermoelectric materials.  This report summarizes mainly on constructing the tester to make it fully operational then beginning to obtain measurements, and finally the process of gathering necessary data for accurate measurements.