Structural investigations of phosphate and aluminofluorophosphate glasses with and without nitridation.

Persistent Link:
http://hdl.handle.net/10150/184778
Title:
Structural investigations of phosphate and aluminofluorophosphate glasses with and without nitridation.
Author:
Fletcher, Joseph Patrick, III.
Issue Date:
1989
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Knowledge of the structural arrangement of the atoms in a solid is an important prerequisite to a detailed understanding of physical and chemical properties. In this work, structural investigations of phosphate (Ca-P-O) and aluminofluorophosphate (Na/Ba-Al-P-O-F) glasses with and without nitridation were performed. Nitrogen was introduced via metal nitrides (AlN, Ba₃N₂, or Ca₃N₂) or ammonia gas treatment of the melt. These glasses were characterized by chemical, thermal and optical techniques. Infrared, Raman, and MASS NMR spectroscopies were used to determine the local coordination and atomic structure of these glasses. The presence of peaks corresponding to P-O-P and PO₂ molecular vibrations in Ca-P-O glasses provided a basis for proposing a calcium metaphosphate glass structure comprised of long chains. As calcium oxide is added to calcium metaphosphate glasses, the long chains are broken up into shorter pyrophosphate units, as indicated by the presence of PO₃²⁻ terminal groups. MASS NMR of Ba-Al-P-O glasses showed that Al occurs as Al(4), Al(6), and either Al(5) or Al(6) linked through Al-O-Al bonds (such as in α-Al₂O₃). The addition of F in both the Ba-Al-P-O-F and Na-Al-P-O-F systems increases the relative abundance of Al(6). The ³¹P peak maxima in the MASS NMR spectra at about -5 to -10 ppm for Ba-Al-P-O-F-N glasses and -9 to -17 for Na-Al-P-O-F-N glass, indicate that pyrophosphate units dominate the structure of these glassy solids. Raman spectroscopy of a series of Al(PO₃)₃-NaF glasses showed that an increase in NaF content causes a shortening of the P-O-P chains and a more disrupted structural network. The presence of P-O-F units were observed only at the higher (>80 mole %) NaF contents. While the complexity of the Raman spectra make it difficult to confirm the presence of P-N bonding, glasses prepared in an ammonia atmosphere (nitrogen content of 1.6 wt%) suggest the possibility of P-N bonding on the basis of a vibrational peak at 826 cm⁻¹.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Metallic glasses -- Research.; Phosphates -- Research.; Raman spectroscopy.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Materials Science and Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Risbud, S. H.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleStructural investigations of phosphate and aluminofluorophosphate glasses with and without nitridation.en_US
dc.creatorFletcher, Joseph Patrick, III.en_US
dc.contributor.authorFletcher, Joseph Patrick, III.en_US
dc.date.issued1989en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractKnowledge of the structural arrangement of the atoms in a solid is an important prerequisite to a detailed understanding of physical and chemical properties. In this work, structural investigations of phosphate (Ca-P-O) and aluminofluorophosphate (Na/Ba-Al-P-O-F) glasses with and without nitridation were performed. Nitrogen was introduced via metal nitrides (AlN, Ba₃N₂, or Ca₃N₂) or ammonia gas treatment of the melt. These glasses were characterized by chemical, thermal and optical techniques. Infrared, Raman, and MASS NMR spectroscopies were used to determine the local coordination and atomic structure of these glasses. The presence of peaks corresponding to P-O-P and PO₂ molecular vibrations in Ca-P-O glasses provided a basis for proposing a calcium metaphosphate glass structure comprised of long chains. As calcium oxide is added to calcium metaphosphate glasses, the long chains are broken up into shorter pyrophosphate units, as indicated by the presence of PO₃²⁻ terminal groups. MASS NMR of Ba-Al-P-O glasses showed that Al occurs as Al(4), Al(6), and either Al(5) or Al(6) linked through Al-O-Al bonds (such as in α-Al₂O₃). The addition of F in both the Ba-Al-P-O-F and Na-Al-P-O-F systems increases the relative abundance of Al(6). The ³¹P peak maxima in the MASS NMR spectra at about -5 to -10 ppm for Ba-Al-P-O-F-N glasses and -9 to -17 for Na-Al-P-O-F-N glass, indicate that pyrophosphate units dominate the structure of these glassy solids. Raman spectroscopy of a series of Al(PO₃)₃-NaF glasses showed that an increase in NaF content causes a shortening of the P-O-P chains and a more disrupted structural network. The presence of P-O-F units were observed only at the higher (>80 mole %) NaF contents. While the complexity of the Raman spectra make it difficult to confirm the presence of P-N bonding, glasses prepared in an ammonia atmosphere (nitrogen content of 1.6 wt%) suggest the possibility of P-N bonding on the basis of a vibrational peak at 826 cm⁻¹.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectMetallic glasses -- Research.en_US
dc.subjectPhosphates -- Research.en_US
dc.subjectRaman spectroscopy.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMaterials Science and Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRisbud, S. H.en_US
dc.contributor.committeememberZelinski, B.en_US
dc.contributor.committeememberRaghavan, S.en_US
dc.contributor.committeememberPemberton, J. E.en_US
dc.identifier.proquest9000772en_US
dc.identifier.oclc702685053en_US
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