Advances In Green Processing To Form Transparent Yb: Lu2O3, Nd:YAG, and ZrO2-Y2O3 Ceramics for High Power Laserand Optical Surface Applications
Abstract
Our previous work demonstrated green processing, sintering and post-HIP methodologies forproducing ceramics of good transparency, up to 8 mol% Yb2O3 in Lu2O3, using commercialpowders not exposed to further chemical processing. Use of other lot numbers of lutetia, aswell as less expensive sources, required a deeper understanding of processing to produce ce-ramics of equal transparency. Spray-drying ball milled powder facilitated sintering compactsto a closed porosity state at lower temperatures. Adjustment of thermolysis temperatureswas required to remove carbon char left behind from pyrolysis of processing organic liquids.In the proposed work, changing the binder/plasticizer to PEG 400, and changing the suspending liquid from acetone will be investigated to eliminate this carbon residue. It wasrecognized that the main impediment to lowering the sintering temperature (which wouldattenuate abnormal grain growth and incorporation of furnace-based impurities), was porosity in the green body on both inter-particle and inter- (spray-dried) granule length scales.Changes in PEG concentration, uniaxial pressing temperature and pressure, vibration, anddirect isopressing will be evaluated to eliminate remnants of spray dried granules in pressedgreen microstructures. A separate investigation of forming highly stable ball-milled suspensions for slip casting in polymer molds will involve pH-shift-based particle surface charging,and addition of anionic polymers for electrosteric repulsion.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 09, 2018
- Source ID
- FA95501810083
Entities
People
- Robert Speyer
Organizations
- Air Force Office of Scientific Research
- Georgia Tech Research Corporation
- United States Air Force