Radiation damage and annealing in graphite implanted with H/sup +//sub 2/ and Mo/sup +/

Journal Article · Fri Apr 15 00:00:00 EDT 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.340997· OSTI ID:5278303

Roth, J; Zuhr, R A; Withrow, S P; Eatherly, W P

Radiation damage due to H/sup +//sub 2/ and Mo/sup +/ implantation into hot-worked pyrolytic graphite and into single-crystal graphite flakes has been studied using 1-MeV /sup 4/He/sup +/ ion channeling. The implant energies used, 35 keV for H/sup +//sub 2/ and 120 keV for Mo/sup +/, yielded ranges of about 1600 and 600 A, respectively. For H/sub 2/ implantation, a partially crystalline surface layer remains after a fluence of 2 x 10/sup 16/ H/cm/sup 2/; this layer is completely disordered at 2 x 10/sup 17/ H/cm/sup 2/. At higher hydrogen fluences a surface layer exfoliates. For Mo implantation the disorder introduced at a fluence of 5 x 10/sup 14/ Mo/cm/sup 2/ is sufficient to prevent channeling throughout the range. For both implant species, complete recrystallization of samples disordered up to the surface occurs for annealing only at temperatures above 2800 K. If a surface layer remains crystalline after implantation, recrystallization proceeds both from the bulk and from the surface, and crystallinity is restored at 2300 K. While hydrogen is known to be released at temperatures between 1100 and 1500 K, Mo remains within its original range distribution up to the temperature of complete recrystallization. At a temperature of 2300 K an ordering of the implanted Mo atoms with respect to the c axis is observed, indicating short-range migration within the range distribution. At 2800 K no more Mo could be found in the analyzed surface layer.

• Research Organization: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5278303
• Journal Information: J. Appl. Phys.; (United States), Vol. 63:8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GRAPHITE
PHYSICAL RADIATION EFFECTS
CRYSTAL STRUCTURE
CRYSTALLIZATION
DAMAGE
HELIUM IONS
HYDROGEN IONS 2 PLUS
ION IMPLANTATION
MEV RANGE 01-10
MOLYBDENUM IONS
PYROLYTIC CARBON
RECRYSTALLIZATION
SURFACES
VERY HIGH TEMPERATURE
CARBON
CATIONS
CHARGED PARTICLES
ELEMENTAL MINERALS
ELEMENTS
ENERGY RANGE
HYDROGEN IONS
IONS
MEV RANGE
MINERALS
MOLECULAR IONS
NONMETALS
PHASE TRANSFORMATIONS
RADIATION EFFECTS
360605* - Materials- Radiation Effects
360602 - Other Materials- Structure & Phase Studies