Showing papers by "Anette M. Karlsson published in 2015"

Monitoring Local Strain in a Thermal Barrier Coating System Under Thermal Mechanical Gas Turbine Operating Conditions

Abstract: Advances in aircraft and land-based turbine engines have been increasing the extreme loading conditions on traditional engine components and have incited the need for improved performance with the use of protective coatings. These protective coatings shield the load-bearing super alloy blades from the high-temperature combustion gases by creating a thermal gradient over their thickness. This addition extends the life and performance of blades. A more complete understanding of the behavior, failure mechanics, and life expectancy for turbine blades and their coatings is needed to enhance and validate simulation models. As new thermal-barrier-coated materials and deposition methods are developed, strides to effectively test, evaluate, and prepare the technology for industry deployment are of paramount interest. Coupling the experience and expertise of researchers at the University of Central Florida, The German Aerospace Center, and Cleveland State University with the world-class synchrotron x-ray beam at the Advanced Photon Source in Argonne National Laboratory, the synergistic collaboration has yielded previously unseen measurements to look inside the coating layer system for in situ strain measurements during representative service loading. These findings quantify the in situ strain response on multilayer thermal barrier coatings and shed light on the elastic and nonelastic properties of the layers and the role of mechanical load and internal cooling variations on the response. The article discusses the experimental configuration and development of equipment to perform in situ strain measurements on multilayer thin coatings and provides an overview of the achievements thus far.

Effect of Water Transport on Swelling and Stresses in PFSA Membranes

Abstract: The mechanical durability of membranes used in proton exchange membrane fuel cells (PEMFC) is directly linked to the stresses that evolve in the membrane during fuel cell operation. The stresses are primarily induced due to the swelling of the membrane as it absorbs water, within the mechanical constraints in the fuel cell assembly. Thus, in order to predict the membrane stresses, the water content in the perfluorosulphonic acid (PFSA) membranes is determined numerically via three different absorption models based on experimentally determined water uptake data from the literature. Two models are based on a single, humidity-dependent Fickian transport coefficient for the bulk PFSA membrane. In the third, two transport properties are modeled to account for a possible difference in transport resistance between the bulk membrane and the outer surface. The membrane sorption behaviors characterized from these three models are then independently incorporated in a representative fuel cell finite element model and subjected to a standard relative humidity (RH) protocol designed for measuring mechanical durability of PEMFCs. The results show that the sorption behavior has a significant effect on the membrane stresses and therefore, may impact the lifetime of the membrane.

Inside the engine environment - Synchrotrons reveal secrets of high-temperature ceramic coatings

Abstract: Woven into a fabric made up of office supplies, tape, and abrasives are several 3M Company products and technologies involving electronic materials and applications. a career spent in 3M’s Corporate research labs has involved project experiences nearly as diverse and wide ranging as 3M itself. Selected topics and experiences are explored by building on some early projects and tracing them forward to current products, research, and critical technology areas. energy storage is discussed, with reference to high-permittivity dielectrics, supercapacitors, and lithium-ion battery components. a variety of electrical components are overviewed, including transparent conductors, high-voltage transmission products, and eMi / eMC materials. Finally, materials for optical products and displays are described, including quantum dot light emitters, ultra-high-barrier film, and light-management materials. Greg Rohrer, W.W. Mullins Professor of Materials Science, Carnegie Mellon university, uSa Title: High-throughput, data-rich experiments and their impact on ceramic science abstract: The automated control of materials characterization instruments and the digital storage of data have created new opportunities for ceramic science. automated control makes it possible to record volumes of data that were not possible in the past, and digital storage makes it possible to compare data in new and difficult to predict ways. This will be illustrated with two examples. First, i will describe combinatorial substrate epitaxy experiments to determine the orientation relationships between phases that result from thin-film growth. Second, i will discuss three-dimensional orientation mapping experiments that provide a rich source of data on microstructures and grain boundaries. Then, i will speculate on opportunities to advance ceramic science through the storage and curation of digital data. The automated control of materials characterization instruments and the digital storage of data have created new opportunities for ceramic science. automated control makes it possible to record volumes of data that were not possible in the past, and digital storage makes it possible to compare data in new and difficult to predict ways. This will be illustrated with two examples. First, i will describe combinatorial substrate epitaxy experiments to determine the orientation relationships between phases that result from thin-film growth. Second, i will discuss three-dimensional orientation mapping experiments that provide a rich source of data on microstructures and grain boundaries. Then, i will speculate on opportunities to advance ceramic science through the storage and curation of digital data. Hiroshi Funakubo, professor, Tokyo institute of Technology, Japan Title: Domain motion under applied electric field in Pb(Zr,Ti)o3 films and their contribution to the piezoelectric properties abstract: Piezoelectric films have been widely investigated for various applications. because of the close correlation between the piezoelectric property and the crystal structure, crystal structure analyses have been conducted mainly for the as-deposited films. Therefore, various methods have been applied to investigate the crystal structure change under an applied electric field. i introduce the quantitative analysis of the crystal structure change under an applied electric field using in situ raman spectroscopy and XrD under an applied electric field. i also evaluate how fast the crystal structure changes under an applied electric field using time-resolved XrD measurement using Spring-8 synchrotron setup. The results clearly indicate the impact of the evaluation, of crystal structure of as-deposited films, and crystal structure change under an applied electric field to understand the piezoelectric properties of Pb(Zr, Ti)o3 films. tutorial on thin-FilM stability Piezoelectric films have been widely investigated for various applications. because of the close correlation between the piezoelectric property and the crystal structure, crystal structure analyses have been conducted mainly for the as-deposited films. Therefore, various methods have been applied to investigate the crystal structure change under an applied electric field. i introduce the quantitative analysis of the crystal structure change under an applied electric field using in situ raman spectroscopy and XrD under an applied electric field. i also evaluate how fast the crystal structure changes under an applied electric field using time-resolved XrD measurement using Spring-8 synchrotron setup. The results clearly indicate the impact of the evaluation, of crystal structure of as-deposited films, and crystal structure change under an applied electric field to understand the piezoelectric properties of Pb(Zr, Ti)o3 films. tutorial on thin-FilM stability This tutorial introduces topics that will be discussed during the symposium, Thin films—Stability, stress relaxation, and properties. researchers and students without extensive background in thin films are encouraged to attend. The tutorial discusses basic concepts, terminology, and results to orient those attending the symposium. Topics will include: • Thin-film growth, microstructure, and stress – epitaxial and textured films • Thin-film stress relaxation – Dislocation mechanisms in thin films – Diffusion in thin films • Thin-film properties – Size-dependent plasticity

Comparison of Thermal Barrier Coating Stresses via High Energy X-Rays and Piezospectroscopy

Abstract: Thermal Barrier Coatings (TBC) have been instrumental in advancing the performance and e�ciency of turbine engines over the last decades. The use of high temperature ce- ramics has allowed increased temperatures by way of protecting the load bearing blade substrate and extending its lifetime. Today there continues to exist the need to under- stand the behavior of the TBC to extend the life and performance of both the TBC and the underlying substrate blades. In this study, the TBC was examined by the use of optical spectroscopy and synchrotron X-Ray di�raction to understand the strain and stress expe- rienced by each of the layers in the coating. Raman and Photoluminescence spectroscopy were employed to examine the thermally grown oxide layer (TGO) and the ceramic top coat and to identify the in uence of variations in temperature distribution. X-Ray di�rac- tion measurements were conducted at the Advanced Photon Source, at Argonne National Laboratory allowing the in-situ investigation of variation in loading conditions including a representative ight cycle. A pre-aged specimen was used for di�raction measurements for a more mature oxide layer. Optical spectroscopy measurements provided high resolution stress maps of the oxide scale. The results from this study provide a more complete un- derstanding as to the behavior of the TBC and its development through the lifetime, and can serve to validate and further the development numerical models.