Quench media effects on iron partitioning and ordering in a lunar glass

M. Darby Dyar, Dunbar P Birnie

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Mössbauer spectroscopy was used to study the microstructures in a synthetic analogue of an Apollo 15 green glass. Different quench rates are found to yield glass structures that are markedly different with respect to iron atom site occupation and charge. Faster quenching rates yield a less dense structure that can accommodate more iron in four-fold sites. In the denser glasses (more slowly cooled) the iron tends to favor higher coordination. The short distances between six- and four-fold sites in the structure (on the order angstroms) provide that the iron will come to its "equilibrium" partitioning value in the structure that is formed on quenching. This structure is representative of the melt at the specific glass transition temperature for the quenching rate experienced. Samples quenched into air exhibit metastable valence state changes. This ionization process occurs during the longer cooling time and may be driven by the structural densification within the melt as cooling takes place. Such structural changes are correlated with the structure of lunar green glass sample # 15426, and possible genetic interpretations are considered.

Original languageEnglish
Pages (from-to)397-412
Number of pages16
JournalJournal of Non-Crystalline Solids
Volume67
Issue number1-3
DOIs
Publication statusPublished - 1984

Fingerprint

Iron
iron
Quenching
Glass
glass
quenching
Cooling
cooling
densification
Densification
occupation
glass transition temperature
Ionization
Spectroscopy
analogs
valence
ionization
Atoms
microstructure
Microstructure

ASJC Scopus subject areas

  • Ceramics and Composites
  • Electronic, Optical and Magnetic Materials

Cite this

Quench media effects on iron partitioning and ordering in a lunar glass. / Darby Dyar, M.; Birnie, Dunbar P.

In: Journal of Non-Crystalline Solids, Vol. 67, No. 1-3, 1984, p. 397-412.

Research output: Contribution to journalArticle

@article{04585f6d80a245b3b8731e8d24ca8fa8,
title = "Quench media effects on iron partitioning and ordering in a lunar glass",
abstract = "M{\"o}ssbauer spectroscopy was used to study the microstructures in a synthetic analogue of an Apollo 15 green glass. Different quench rates are found to yield glass structures that are markedly different with respect to iron atom site occupation and charge. Faster quenching rates yield a less dense structure that can accommodate more iron in four-fold sites. In the denser glasses (more slowly cooled) the iron tends to favor higher coordination. The short distances between six- and four-fold sites in the structure (on the order angstroms) provide that the iron will come to its {"}equilibrium{"} partitioning value in the structure that is formed on quenching. This structure is representative of the melt at the specific glass transition temperature for the quenching rate experienced. Samples quenched into air exhibit metastable valence state changes. This ionization process occurs during the longer cooling time and may be driven by the structural densification within the melt as cooling takes place. Such structural changes are correlated with the structure of lunar green glass sample # 15426, and possible genetic interpretations are considered.",
author = "{Darby Dyar}, M. and Birnie, {Dunbar P}",
year = "1984",
doi = "10.1016/0022-3093(84)90165-0",
language = "English",
volume = "67",
pages = "397--412",
journal = "Journal of Non-Crystalline Solids",
issn = "0022-3093",
publisher = "Elsevier",
number = "1-3",

}

TY - JOUR

T1 - Quench media effects on iron partitioning and ordering in a lunar glass

AU - Darby Dyar, M.

AU - Birnie, Dunbar P

PY - 1984

Y1 - 1984

N2 - Mössbauer spectroscopy was used to study the microstructures in a synthetic analogue of an Apollo 15 green glass. Different quench rates are found to yield glass structures that are markedly different with respect to iron atom site occupation and charge. Faster quenching rates yield a less dense structure that can accommodate more iron in four-fold sites. In the denser glasses (more slowly cooled) the iron tends to favor higher coordination. The short distances between six- and four-fold sites in the structure (on the order angstroms) provide that the iron will come to its "equilibrium" partitioning value in the structure that is formed on quenching. This structure is representative of the melt at the specific glass transition temperature for the quenching rate experienced. Samples quenched into air exhibit metastable valence state changes. This ionization process occurs during the longer cooling time and may be driven by the structural densification within the melt as cooling takes place. Such structural changes are correlated with the structure of lunar green glass sample # 15426, and possible genetic interpretations are considered.

AB - Mössbauer spectroscopy was used to study the microstructures in a synthetic analogue of an Apollo 15 green glass. Different quench rates are found to yield glass structures that are markedly different with respect to iron atom site occupation and charge. Faster quenching rates yield a less dense structure that can accommodate more iron in four-fold sites. In the denser glasses (more slowly cooled) the iron tends to favor higher coordination. The short distances between six- and four-fold sites in the structure (on the order angstroms) provide that the iron will come to its "equilibrium" partitioning value in the structure that is formed on quenching. This structure is representative of the melt at the specific glass transition temperature for the quenching rate experienced. Samples quenched into air exhibit metastable valence state changes. This ionization process occurs during the longer cooling time and may be driven by the structural densification within the melt as cooling takes place. Such structural changes are correlated with the structure of lunar green glass sample # 15426, and possible genetic interpretations are considered.

UR - http://www.scopus.com/inward/record.url?scp=48549109930&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=48549109930&partnerID=8YFLogxK

U2 - 10.1016/0022-3093(84)90165-0

DO - 10.1016/0022-3093(84)90165-0

M3 - Article

VL - 67

SP - 397

EP - 412

JO - Journal of Non-Crystalline Solids

JF - Journal of Non-Crystalline Solids

SN - 0022-3093

IS - 1-3

ER -