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Final report for Grant No. DOE/DE-FG02-98ER14909: Experimental and modeling studies of nanometer aerosol filtration

Description: The primary objective is to perform a fundamental study of filtration of nanoparticles, and to obtain filtration knowledge necessary to design particle collection devices/systems for nanoparticle processing and for preventing nanoparticle emissions into the environment. The research covered a wide area relevant to nanoparticle filtration, under these main topics: (1) nanoparticle filtration and molecular dynamics simulation, (2) nanoparticle virtual impactor, (3) particle transport under low pressure, and (4) development of a high-throughput nanoparticle generator. A number of novel tools and numerical models have been developed under the DOE support.
Date: December 10, 2002
Creator: Pui, David Y. H. & Chen, Da-Ren
Partner: UNT Libraries Government Documents Department

Nano-precipitation in hot-pressed silicon carbide

Description: Heat treatments at 1300 degrees C, 1400 degrees C, 1500 degrees C, and 1600 degrees C in Ar were found to produce nanoscale precipitates in hot-pressed silicon carbide containing aluminum, boron, and carbon sintering additives (ABC-SiC). The precipitates were studied by transmission electron microscopy (TEM) and nano-probe energy-dispersive X-ray spectroscopy (nEDS). The precipitates were plate-like in shape, with a thickness, length and separation of only a few nanometers, and their size coarsened with increasing annealing temperature, accompanied by reduced number density. The distribution of the precipitates was uniform inside the SiC grains, but depleted zones were observed in the vicinity of the SiC grain boundaries. A coherent orientation relationship between the precipitates and the SiC matrix was found. Combined high-resolution electron microscopy, computer simulation, and nEDS identified an Al4C3-based structure and composition for the nano-precipitates. Most Al ions in SiC lattice exsolved as precipitates during the annealing at 1400 to 1500 degrees C. Formation mechanism and possible influences of the nanoscale precipitates on mechanical properties are discussed.
Date: May 16, 2000
Creator: Zhang, Xiao Feng; Sixta, Mark E.; Chen, Da & De Jonghe, Lutgard C.
Partner: UNT Libraries Government Documents Department

Abrasive wear behavior of heat-treated ABC-silicon carbide

Description: Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.
Date: June 17, 2002
Creator: Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O. & De Jonghe, Lutgard C.
Partner: UNT Libraries Government Documents Department