Plasma-deposited Beryllium Carbide Coatings for Application to Inertial Confinement Fusion
Composite coatings containing beryllium are prepared by plasma-enhanced chemical vapor deposition at a substrate temperature as low as 250 °C in a radio-frequency-induced cylindrical plasma reactor. Diethylberyllium is used as the precursor together with hydrogen as a coreactant gas. These coatings are characterized by Auger electron spectroscopy (AES), X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, electrical resistivity, and thermogravimetric analysis. AES indicates that the composition of the coatings reaches a steady level at a depth of 300 angstroms from the surface and maintains a constant composition throughout the thickness of the coatings. The characterization studies establish the dominant phase to be Be2C. The coatings are also resistant to oxidation and hydrolysis in dry/moist air unlike bulk Be2C. It is found that the coatings deposited close to the diethylberyllium inlet contain amorphous beryllium that is homogeneously dispersed in a Be2C matrix. Films of approximately 5-μm thickness with an acceptable permeability to H2 are prepared. These coatings meet some of the major requirements of the ablator material for inertial confinement fusion target capsules.
W. Shih et al., "Plasma-deposited Beryllium Carbide Coatings for Application to Inertial Confinement Fusion," Fusion Technology, American Nuclear Society (ANS), Jan 2000.
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