Ching-Fong Chen
Los Alamos National Laboratory
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Publication
Featured researches published by Ching-Fong Chen.
Journal of Materials Science | 2013
Ching-Fong Chen; Quinn R. Marksteiner; Graham King; Thomas A. Wynn; Michael B. Treiman; Dale A. Dalmas; Anna Llobet; W.B. Haynes; Dennis R. Guidry; Pallas A. Papin
The sol–gel method was used to synthesize two different Ba0.75Sr0.25Ti0.95Zr0.05O3 powders: one of high purity and the other of low purity. These two sol–gel-synthesized powders show two distinct particle sizes and surface areas. The slip casting method was applied to these two sol–gel powders followed by a pressureless sintering, which shows large differences in sintered density and grain size for the pressureless sintered disks. Neutron powder diffraction shows a transition to the nonpolar cubic Pm–3m space group at higher temperatures for both materials. Pair distribution function analysis was used to examine the local displacements of the Ti4+ and Zr4+ cations. The dielectric constant, loss tangent, and bias were measured on these two materials.
Review of Scientific Instruments | 2017
Quinn R. Marksteiner; Michael B. Treiman; Ching-Fong Chen; W.B. Haynes; M. T. Reiten; Dale A. Dalmas; Elias Pulliam
A resonant cavity method is presented which can measure loss tangents and dielectric constants for materials with dielectric constant from 150 to 10 000 and above. This practical and accurate technique is demonstrated by measuring barium strontium zirconium titanate bulk ferroelectric ceramic blocks. Above the Curie temperature, in the paraelectric state, barium strontium zirconium titanate has a sufficiently low loss that a series of resonant modes are supported in the cavity. At each mode frequency, the dielectric constant and loss tangent are obtained. The results are consistent with low frequency measurements and computer simulations. A quick method of analyzing the raw data using the 2D static electromagnetic modeling code SuperFish and an estimate of uncertainties are presented.
Journal of Materials Science | 2014
Ching-Fong Chen; Quinn R. Marksteiner; Matthew R. Reiten; Thomas A. Wynn; Dennis R. Guidry
We propose an innovative idea to bond the dielectric barium strontium zirconium titanate (BSTZO) plates with magnesium oxide (MgO) as the spacers to achieve a hermetic module without any air gaps between the dielectric and the spacer. The gold metallization can be applied across the whole assembly to create an integrated electrode. The gold metallization also eliminates pressure contact by external copper plates assemblies, which are required to achieve good contacts between the copper plates and the metallized surfaces of the BSTZO. The MgO spacers are processed using a dry-pressing and pressureless-sintering method. The thermal expansion coefficient (CTE) of BSTZO and MgO spacer was measured. In addition to matching the CTE between BSTZO dielectric and the MgO spacer, it is also critical to develop a good bonding material with CTE matching to BSTZO and MgO spacer. The effect of CTE for various bonding compositions on the dielectric properties was thoroughly studied and reported. The mechanism explaining the high and low dielectric constants for the laminates is proposed and discussed based on the CTE results and their effect on microstructural development.
Archive | 2015
P. Dickerson; Deborah Ann Summa; C. Liu; Laura Arias Tucker; Ching-Fong Chen; Beverly Aikin; Daniel Adrian Aragon; Timothy Vance Beard; Joel D. Montalvo; Maria Isela Pena; David E. Dombrowski
The goals of this project were to demonstrate reliable, reproducible solid state bonding of aluminum 6061 alloy plates together to encapsulate DU-10 wt% Mo surrogate fuel foils. This was done as part of the CONVERT Fuel Fabrication Capability effort in Process Baseline Development . Bonding was done using Hot Isotatic Pressing (HIP) of evacuated stainless steel cans (a.k.a HIP cans) containing fuel plate components and strongbacks. Gross macroscopic measurements of HIP cans prior to HIP and after HIP were used as part of this demonstration, and were used to determine the accuracy of a finitie element model of the HIP bonding process. The quality of the bonding was measured by controlled miniature bulge testing for Al-Al, Al-Zr, and Zr-DU bonds. A special objective was to determine if the HIP process consistently produces good quality bonding and to determine the best characterization techniques for technology transfer.
Nano Energy | 2015
Ching-Fong Chen; Graham King; Robert M. Dickerson; Pallas A. Papin; Shiva Gupta; William Kellogg; Gang Wu
Journal of the American Ceramic Society | 2010
Ching-Fong Chen; F. P. Doty; Ronald J. T. Houk; Raouf O. Loutfy; Heather M. Volz; Pin Yang
Journal of the American Ceramic Society | 2011
Ching-Fong Chen; David W. Reagor; Steven J. Russell; Quinn R. Marksteiner; Lawrence M. Earley; Dale A. Dalmas; Heather M. Volz; Dennis R. Guidry; Pallas A. Papin; Pin Yang
Journal of the American Ceramic Society | 2012
Ching-Fong Chen; Anna Llobet; Geoff L. Brennecka; Robert T. Forsyth; Dennis R. Guidry; Pallas A. Papin; Rodney J. McCabe
Journal of Materials Science | 2017
Ching-Fong Chen; Reeju Pokharel; Michael J. Brand; Eric L. Tegtmeier; B. Clausen; David E. Dombrowski; Timothy Lee Ickes; Ricardo A. Lebensohn
Journal of the American Ceramic Society | 2018
Ching-Fong Chen; Ron A. Synowicki; Michael J. Brand; Eric L. Tegtmeier; Joel D. Montalvo; Jacob Ivy; Geoff L. Brennecka; Zach Seeley; Nerine J. Cherepy; S.A. Payne