ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
We report an investigation of millimeter-wave processing of yttria for fabrication oftransparent, high-strength polycrystalline laser hosts for high energy laser (HEL) applications.Advantages of polycrystalline, compared to single-crystal laser host materials, include lowerprocessing temperature, higher gain with flexibility of higher dopant concentrations, cheaperfabrication, and larger-size devices. Millimeter-wave processing is an alternative method to solvethe problems of both conventional vacuum and low-frequency microwave sintering, such as lowheating rate, poor coupling and thermal gradients. A major component of the millimeter-waveprocessing facility is a 20-kW, continuous-wave, 83-GHz gyrotron oscillator. Yttria has beensuccessfully sintered with millimeter-wave beams with up to 99% theoretical density. A partiallytransparent yttria sample has also been achieved using the millimeter-wave sintering process [1].Several factors impact the quality of the sintered material including the presence of agglomerates,impurities, processing atmosphere, sintering aids, and thermal gradients. Efforts to improve thetransparency will be discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.511.pdf
