Metastability in the MgAl2O4-Al2O3 System

Wilkerson, Kelley R.; Smith, Jeffrey D.; Hemrick, James G.

doi:10.1111/ijac.12294

Title: Metastability in the MgAl₂O₄-Al₂O₃ System

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Abstract

Aluminum oxide must take a spinel form ( γ-Al₂O₃) at elevated temperatures in order for extensive solid solution to form between MgAl₂O₄ and α-Al₂O₃. The solvus line between MgAl₂O₄ and Al₂O₃ has been defined at 79.6 wt% Al₂O₃ at 1500°C, 83.0 wt% Al₂O₃ at 1600°C, and 86.5 wt% Al₂O₃ at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al₂O₃ at elevated temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al₂O₃ rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.

Authors:

Wilkerson, Kelley R. ^[1]; Smith, Jeffrey D. ^[1]; Hemrick, James G. ^[2]

Missouri Univ. of Science and Technology, Rolla, MO (United States). Materials Science and Engineering
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Mechanical Properties & Mechanics Group

Publication Date:: Tue Jul 22 00:00:00 EDT 2014

Research Org.:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:: 1185327

Grant/Contract Number:: AC05-00OR22725; 14954

Resource Type:: Accepted Manuscript

Journal Name:: International Journal of Applied Ceramic Technology

Additional Journal Information:: Journal Volume: 11; Journal Issue: 6; Journal ID: ISSN 1546-542X

Publisher:: Wiley

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Spinel; Phase Diagram

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                    Wilkerson, Kelley R., Smith, Jeffrey D., and Hemrick, James G. Metastability in the MgAl2O4-Al2O3 System.  United States: N. p., 2014. 
Web.  doi:10.1111/ijac.12294.

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                    Wilkerson, Kelley R., Smith, Jeffrey D., & Hemrick, James G. Metastability in the MgAl2O4-Al2O3 System.  United States.  https://doi.org/10.1111/ijac.12294

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                    Wilkerson, Kelley R., Smith, Jeffrey D., and Hemrick, James G. Tue .  
"Metastability in the MgAl2O4-Al2O3 System".  United States.  https://doi.org/10.1111/ijac.12294.  https://www.osti.gov/servlets/purl/1185327.

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@article{osti_1185327,

  title        = {Metastability in the MgAl2O4-Al2O3 System},

  author       = {Wilkerson, Kelley R. and Smith, Jeffrey D. and Hemrick, James G.},

  abstractNote = {Aluminum oxide must take a spinel form ( γ-Al2O3) at elevated temperatures in order for extensive solid solution to form between MgAl2O4 and α-Al2O3. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been defined at temperatures up to 1700°C which could have significant implications for material processing and properties. Additionally, initial processing could have major implications on final chemistry. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevated temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present, resulting in no eutectic crystal formation during solidification.},

  doi          = {10.1111/ijac.12294},

  journal      = {International Journal of Applied Ceramic Technology},

  number       = 6,

  volume       = 11,

  place        = {United States},

  year         = {Tue Jul 22 00:00:00 EDT 2014},

  month        = {Tue Jul 22 00:00:00 EDT 2014}

}

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Title: Metastability in the MgAl2O4-Al2O3 System

Abstract

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Title: Metastability in the MgAl₂O₄-Al₂O₃ System