TY - JOUR
T1 - The effect of pyrolytic carbon coating on gas emission and sublimation of graphite induced by pulse laser beams
AU - Muroga, T.
AU - Kamezaki, H.
AU - Tokunaga, K.
AU - Yoshida, N.
N1 - Funding Information:
The authors are grateful to Toyo Tanso Co. Ltd for supplying the specimens. Also, they would like to acknowledge Professors T. Yamashina and T. Hino of Hokkaido University for arranging the specimen matrix. This work was supported by a Grant-in-Aid for Fusion Research sponsord by Monbusho, Japanese Ministry of Education, Science and Culture.
PY - 1990/12/3
Y1 - 1990/12/3
N2 - The emission and sublimation of graphites coated with pyrolytic carbon (PyC) has been measured under irradiation with pulse laser beams to examine the effects of pulse heat load on the role of the coating. Under a heat load density of 640 MW/m2 and a pulse length of 1 ms, gas emission, sublimation and vacuum degradation are enhanced by the PyC coating. This is mainly due to very low thermal conductivity of the PyC film in the surface normal direction resulting in an enhanced temperature rise during the heat load. On the other hand, the gas emission, sublimation and vacuum degradation of the coated specimens were small relative to the non-coated specimens when compared on the basis of the measured peak surface temperature. Thus the surface coating with PyC may be effective in reducing the gas emission when the carbon temperature increases gradually but can be harmful to vacuum and surface stability in the case of pulse high heat load.
AB - The emission and sublimation of graphites coated with pyrolytic carbon (PyC) has been measured under irradiation with pulse laser beams to examine the effects of pulse heat load on the role of the coating. Under a heat load density of 640 MW/m2 and a pulse length of 1 ms, gas emission, sublimation and vacuum degradation are enhanced by the PyC coating. This is mainly due to very low thermal conductivity of the PyC film in the surface normal direction resulting in an enhanced temperature rise during the heat load. On the other hand, the gas emission, sublimation and vacuum degradation of the coated specimens were small relative to the non-coated specimens when compared on the basis of the measured peak surface temperature. Thus the surface coating with PyC may be effective in reducing the gas emission when the carbon temperature increases gradually but can be harmful to vacuum and surface stability in the case of pulse high heat load.
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U2 - 10.1016/0022-3115(90)90088-5
DO - 10.1016/0022-3115(90)90088-5
M3 - Article
AN - SCOPUS:0025550212
SN - 0022-3115
VL - 176-177
SP - 450
EP - 454
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
IS - C
ER -