Ceramics Subcommittee Agenda and Minutes

UNAPPROVED MINUTES
Ceramic Subcommittee
21 March 2007
ICDD Headquarters, Conference Room A
Chairman - Peter Y. Zavalij

Minutes Approved
The minutes from the March 2006 Ceramic Subcommittee were approved.

Board of Directors' Liaison Report – E. Antipov
Two motions were approved by the Board of Directors from last year:

  • P. Zavalij moved that a sum of $3,000 be allocated for Task Group members to attend the ICDD Annual Meeting and Ceramic Subcommittee Meeting.
  • P. Zavalij moved that the ICDD initiate and create (when populated) a new subfile “Thermoelectric Materials” that will by supervised by Winnie Wong-Ng. The subfile has been initiated but not formally created because it has not been populated yet.

Development of Subfiles
Details were reviewed for development of property subfiles:

  1. Subfile Initiation Prerequisites: Important properties, a strict/exact definition, and an assigned task group of experts.
  2. Adding a Subfile to the PDF: The subfile must be well populated, with primary entries and links to alternative entries.
  3. Subfile Maintenance & Population: Review of existing entries and annual review of new database entries.
  4. Scheme of Adding New Entries:
    1. Mark candidates from list (full list may be filtered by general selection criteria).
    2. Review marked entries with all data.
    3. Add properties, comments and links to the database

There was also discussion on the current classification of subfiles by a number of types, including properties (i.e. semiconductors, ferroelectrics) and classes of compound (i.e. perovskites), and how these types could be organized.

Ionic Conductors (V. Nalbandyan/G.V. Subba Rao)
The ionic conductor (ION) subfile includes compounds where conduction is primarily ionic (transference number > 0.95) which meet minimum conductance requirements of 10 -5 s/cm within the solid state existence range.

Last year, Set 57 was reviewed (526 pre-selected entries) and 25 new ION entries were marked. 50 descriptions of ionic conductors were prepared and added to 33 previous ION descriptions submitted by V. Nalbandyan and 24 ION descriptions submitted by G.V. Subba Rao.

Superconductors (E. Antipov/W. Wong-Ng)
Set 57 was reviewed last year for superconductor (SCM) entries, and 15 superconductors and 4 superconductor related materials were marked as SCM entries. Critical temperatures (T C ) were compiled and added for superconductors in the PDF Sets 1-51 (249 compounds) from the Handbook of Chemistry and Physics, 86 th Ed. (2005-2006) CRC Press.

A list of superconductor systems were examined, with patterns and samples prepared by W. Wong-Ng, J. Kaduk, Z. Yang and J. Frank (predominantly doped barium cuprates, titanates and niobiates).

L. Lanno will send E. Antipov full AIDS runs with the next release after he identifies the superconductors.

Microwaves (W. Wong-Ng)
The microwave (MIC) subfile has been designated to represent dielectric oxides containing Ta, Nb, Ti, W, or Zr in combination with specific divalent (Ba, Sr, Ca, Mg, Zn) and trivalent (Ln) metals. Last year, 117 new microwave materials (from review of Set 57) were assigned the MIC subfile mark. It should be noted that very few of these materials are currently used in microwave applications, but based on composition and crystallography these materials have the potential to be investigated for microwave applications.

Thermoelectric Materials (W. Wong-Ng)
Thermoelectric materials are able to directly convert heat into electricity (and vice versa) and have potential applications in power generation from waste heat and cooling using electricity. Thermoelectric materials are characterized by high thermoelectric figures of merit (Z=S 2 /??=S 2 s/?) due to a high Seeback coefficient (S), high electrical conductivity (s) and low thermal conductivity (?).

A goal is to identify enough thermoelectric materials to populate a subfile (TE) for inclusion in the next release of the PDF database.

A thermoelectric materials task group has been formed with the following five members:

-Claudia Rawn from Oak Ridge National Laboratory (skutterudites)
-Terry Tritt from Clemson University (chalcogenides, complex pentatellurides)
-George Nolas from Univeristy of South Florida (clathrates)
-Winnie Wong-Ng from NIST (oxides, half-Heuslers and metal silicides)
-Evan Thomas from NIST (pnictides and other new materials)

W. Wong-Ng will supply S. Kabekkodu, by September, with a list of patterns that will be flagged as thermoelectric materials, based on information supplied by S. Kabekkodu which will include chemical formulas, lattice parameters, detailed structures and references.

Battery Materials (P. Zavalij)
Battery materials should have a minimum capacity of 100mAh/g, and rechargeable batteries should exhibit no loss in capacity for a minimum of 10 cycles.

Review of Set 57 led to the marking of 6 new battery material entries and 5 pre-selected BAT entries were removed.

Semiconductors (M. Delgado)
Compounds falling within the semiconductor (SEM) subfile have intermediate conductivity of between insulators and conductors of 10 -10 to 10 4 W -1 cm -1 (S cm -1 ). Many semiconductors are considered to be derived from the Elemental IV Semiconductor through a systematic derivation carried out based on 2 simple rules:

•  Number of valence electrons per atom (VEC) must be four.

•  Number of valence electrons per anion (VEC A ) must be eight.

There are currently 1650 SEM entries in the PDF.

Bioceramics (S. Misture)
There was not much activity in the bioceramics (BIO) subfile this year.

Ferroelectric Materials (V. Nalbandyan)
The ferroelectrics (FER) subfile is made up of materials with ordinary dielectric high-temperatures phases which undergo phase transition to low-temperature polar phases which can be polarized and switched by applied fields.

After review of Set 57, 10 new FER entries were marked last year. An additional 32 possible FER entries were identified based on composition and symmetry, and 13 potential FER entries were noted which require a literature search to determine their status.

Giant Magneto Resistance (P. Zavalij)
P. Zavalij has several giant magneto resistance (GMR) candidates and hopefully will be able to populate the GMR subfile for the next PDF release.

Motion 1
The Ceramic Subcommittee recommends to the Technical Committee that a sum of up to $3,000 be allocated for meeting of Ceramics Task Group members during 2008 ICDD Annual Meeting/2007 Denver Conference.

Motion passed.