X-Ray Diffraction Topography of Sapphire for Windows and Domes
David R. Black
X-ray diffraction topography has been used as a nondestructive characterization tool to investigate single-crystal sapphire for window and dome applications. A variety of examples are shown that demonstrate the utility of x-ray diffraction imaging as a diagnostic tool to study the growth, fabrication and processing of sapphire. These examples include: characterizing the effect of different surface finishing operations on the amount of induced subsurface damage; observing microstructural changes as a result of processes used to strengthen sapphire; and studying the relationship between surface flaws and fracture strength. Diffraction imaging can also function as a baseline technique to verify the utility of other existing characterization methods and to help evaluate new techniques for application on the shop floor. Results for dimpling of ground surfaces show that an apparently polished dimple may have significant surface damage resulting form dimpling process.
Proceedings 7th DoD Electromagnetic Windows Symposium