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Analytical electron microscopy of precipitates in ion-implanted MgAl{sub 2}O{sub 4} spinel

Technical Report ·
DOI:https://doi.org/10.2172/34295· OSTI ID:34295
 [1]; ;  [2]
  1. Oak Ridge Inst. for Science and Education, TN (United States)
  2. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
Magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) is being considered as an insulator material within proposed fusion reactors where considerable radiation fields are anticipated. Analytical electron microscopy (AEM) has been used to investigate precipitates within MgAl{sub 2}O{sub 4} spinel following implantation of Al{sup +}, Mg{sup +}, or Fe{sup 2+} ions. Combined diffraction experiments, energy dispersive X-ray spectrometry (EDS), electron energy-loss spectrometry (EELS), and energy-filtered imaging were employed to identify and characterize precipitates observed in the implanted ion region. Diffraction studies suggested these are metallic aluminum colloids, although EELS and energy-filtered images revealed this to be the case only for the Al{sup +} and Mg{sup +} implantations, and not for Fe{sup 2+} ion implantations. Multiple-least-squares (MLS) fitting of EELS spectra was employed to quantify the volume fraction of metallic aluminum when present in the implanted ion region. Energy-filtered images of the implanted ion region clearly show the colloid distribution in the Al{sup +} and Mg{sup +} implanted spinel. Energy-filtered images from the Fe {sup 2+} ion implanted spinel indicate that the features visible in diffraction contrast cannot be associated with either metallic aluminum or iron-rich precipitates.
Research Organization:
Oak Ridge National Lab., TN (United States); Oak Ridge Inst. for Science and Education, TN (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC05-84OR21400; AC05-76OR00033
OSTI ID:
34295
Report Number(s):
CONF-941144--92; ON: DE95007406
Country of Publication:
United States
Language:
English