Metals and Alloys Subcommittee Agenda and Minutes

APPROVED MINUTES
Metals and Alloys Subcommittee
March 20, 2002
Chairman: Howard Jones

Call to Order and Attendance

Howard Jones called the Metals and Alloys (M&A) Subcommittee meeting to order about 10:10 a.m. The Attendance List is on file at Headquarters, and the agenda is shown below.

1. Call to Order and Attendance
2. Approval of Minutes
3. Board of Directors Items (Jeff Dann)
4. Set 52 Review (Pete Wallace)
5. New Calculated M&A Patterns (Suri Kabekkodu)
6. M&A Working Group (Pete Wallace)
A. Pearson Symbol Code Index (PSCI) Review
B. Strukturbericht Symbol Index (SSI) Updating
C. Common Names Index (CNI) Updating
7. Review of Duplicate Patterns (Jeff Dann)
8. Indexing of "O" Patterns (Bill Mayo)
9. Proposed Calculated Patterns Round Robin (Howard Jones)
10. New Items
11. Adjournment

Approval of Minutes

One change to the M&A Subcommittee minutes of March 2001 was made. In the last sentence under Adjournment, the chairman's name was incorrectly given as Johnson. This was changed to Jones, and the minutes were approved.

Board of Directors Items

The Board of Directors passed both motions from the previous M&A meeting. (One dealt with default search conditions for ICDD computer products, and the other requested input of the Pearson Symbol Code Index review into the ICDD master database.)

Set 52 Review (Pete Wallace)

The review of new M&A patterns is complete through March 2002, and the results have been returned to ICDD Headquarters.

New Calculated M&A Patterns (Suri Kabekkodu)

S. Kabekkodu is calculating powder diffraction patterns from NIST data sets for M&A materials. He has worked on the first 7960 data sets, and found that 4043 passed initial screening and yielded acceptable powder patterns. These patterns will be the first to be added to the Powder Diffraction File (PDF). Patterns that did not pass the initial screening will be the subject of further work to ensure that as many as possible can be added to the PDF, and M&A volunteers will assist as required. A second group of data sets with 12,517 entries will be worked on after the first group with the hope that 6000 (or more) patterns may be added to the following year's PDF. (S. Kabekkodu's report is Attachment A.)

M&A Working Group (Pete Wallace)

The M&A Working Group met March 16-19, 2002 with Mike Bennett, Jeff Dann, Howard Jones, and Pete Wallace present. Highlights of this meeting are given in the next three sections.

Pearson Symbol Code Index (PSCI) Review

The first phase of this review is approaching completion (see Attachment B for the review status). Tasks remaining include review of pages 41-120 of the hexagonal entries and some quality assurance reviews. Our goal is to complete the first phase of the PSCI review in a few months and then move on to the next phase which will include (a) new patterns from the NIST data and (b) other M&A subfile additions since November 1998, the cutoff date for the first phase.

Strukturbericht Symbol Index (SSI) Updating

The M&A SSI is a cross-reference table that helps the user go from a Strukturbericht Symbol to a modern prototype structure. The M&A SSI has been updated and the resultant table given to ICDD editorial personnel for inclusion in ICDD products where the SSI is used. The updated SSI is more useful and includes the space group and number, PDF number, and quality mark for each entry.

Common Names Index (CNI) Updating

The M&A Common Names Index updating will begin in the next few months. The work will involve (a) ensuring that PDF numbers are for the best example available, (b) adding new entries, and (c) performing some editorial work and cleanup. We have an electronic file to perform the work on.

Review of Duplicate Patterns (Jeff Dann)

ICDD volunteers have completed (a) all of the duplicate review for the M&A subfile, and (b) half of the inorganic PDF.

Indexing of "O" Patterns (Bill Mayo)

B. Mayo could not attend this meeting.

Proposed Calculated Patterns Round Robin (Howard Jones)

For some years now, the M&A Subcommittee has had a set of test data for calculating powder diffraction patterns of metallic phases. L. Calvert put this data together for the purpose of testing whether a powder pattern calculation program could correctly calculate powder diffraction patterns, but the "correct" answers for the data were not determined.

H. Jones is now proposing a calculated pattern round robin to determine the correct answers for the test data. In a second phase of the round robin, participants would calculate powder patterns for materials not now in the database. People who would like to participate in the round robin should contact Howard via e-mail at joneshow@pweh.com.

New Items

A New Approach to Editing Relational Database Information (Frank McClune)

F. McClune mentioned that he is using information in the Editorial Department's new relational database to look for inconsistencies in how prototype structure designations have been applied in the past. For example, one can search for a prototype structure descriptor such as wurtzite and learn all the correct and sometimes incorrect ways this descriptor has been used.

Prototype Structure Profiles (Howard Johnson)

H. Jones and other members of the M&A Working Group are creating profiles of prototype structures to aid in assigning a prototype structure to a material. At present, their focus is on the observed ranges in Pearson symbol codes, lattice parameters, axial ratios and atomic volumes as well as what types of elements have been observed to form the structure. In the ensuing discussion, meeting attendees suggested including Goldschmidt radii, the hkls of strong lines, and xyz coordinates. More information on this work will be presented at the next M&A Subcommittee meeting.

Archiving Atomic Structural Data (Cam Hubbard)

C. Hubbard suggested that the NIST atomic structural data be archived, and then the following motion was made by H. Jones and seconded by P. Wallace.

Motion 1: The Metals and Alloys Subcommittee recommends to the Technical Committee that where permissible, Atomic Structural Data used for calculating powder patterns be stored in the ICDD relational database.

The motion passed 8-0-0.

Adjournment

H. Jones adjourned the meeting at about 11:02 a.m.