Pressureless Sintering of Zirconium Diboride: Particle Size and Additive Effects
Zirconium diboride (ZrB2) was densified by pressureless sintering using <4-wt% boron carbide and/or carbon as sintering aids. As-received ZrB2 with an average particle size of ∼2 μm could be sintered to ∼100% density at 1900°C using a combination of boron carbide and carbon to react with and remove the surface oxide impurities. Even though particle size reduction increased the oxygen content of the powders from ∼0.9 wt% for the as-received powder to ∼2.0 wt%, the reduction in particle size enhanced the sinterability of the powder. Attrition-milled ZrB2 with an average particle size of <0.5 μm was sintered to nearly full density at 1850°C using either boron carbide or a combination of boride carbide and carbon. Regardless of the starting particle size, densification of ZrB2 was not possible without the removal of oxygen-based impurities on the particle surfaces by a chemical reaction.
G. Hilmas et al., "Pressureless Sintering of Zirconium Diboride: Particle Size and Additive Effects," Journal of the American Ceramic Society, John Wiley & Sons, Dec 2007.
The definitive version is available at http://dx.doi.org/10.1111/j.1551-2916.2007.02169.x
Materials Science and Engineering
United States. Air Force. Office of Scientific Research
Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)
National Science Foundation (U.S.)
Keywords and Phrases
Oxygen Content; Pressureless Sintering; Zirconium Diboride
Article - Journal
© 2007 John Wiley & Sons, All rights reserved.