Microstructural characterization of iron implanted sapphire nanocomposites

Technical Report · Sat Dec 31 04:00:00 EST 1994

DOI:https://doi.org/10.2172/102181· OSTI ID:102181

Ren, S X; McHargue, C J ^[1]; Allard, L F; Chen, Y; Hunn, J D; Lucas, B N; Williams, R K ^[2]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
2. Oak Ridge National Lab., TN (United States)

Nanocomposites of iron in sapphire ({alpha}-Al{sub 2}O{sub 3}) prepared by ion implantation have been studied as a model to investigate the potential of such materials for applications in high technology areas. The implantation was performed with 160 keV ions at several doses; the nanocomposites were then annealed at selected temperatures between 700 and 1,400 C in an Ar-4%H{sub 2} atmosphere for 1 hour. Rutherford backscattering spectroscopy and high resolution transmission electron microscopy (TEM) were used to characterize the structure of these nanocomposites. Measurements showed that damage depth extended to about 300 nm and the embedded iron extended to about 200 nm. This region became amorphous when the fluence reaches 2 {times} 10{sup 17} Fe/cm{sup 2} at this energy. Thermal annealing could be used to restore the crystallinity to the damaged near-surface region, to form the metallic colloids, and also to coarsen the precipitates. In the case of high dose implantation, oriented precipitates with diameters of 2 to 3 nm were identified by TEM techniques as {alpha}-Fe which had the following orientation relationship with the sapphire matrix: <111>{sub Fe} {parallel} <310>{sub Sapphire} and {l_brace}01{bar 1}{r_brace}{sub Fe} {parallel} {l_brace}006{r_brace}{sub Sapphire}. The optical density and luminescence spectra were also measured. The predominant defects were oxygen vacancies with two electrons (F center) at the known absorption peak of 200 nm.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 102181
• Report Number(s): CONF-941144--170; ON: DE95014260
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
AMORPHOUS STATE
COMPOSITE MATERIALS
CONTROLLED ATMOSPHERES
EXPERIMENTAL DATA
GRAIN ORIENTATION
ION IMPLANTATION
IRON
IRON IONS
IRON-ALPHA
MICROSTRUCTURE
OPTICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
PRECIPITATION
RADIATION DOSES