1987 Fiscal Year Final Research Report Summary
Studies on Whisker of Ice Crystals
| Project/Area Number |
60460229
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | Hokkaido University |
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Principal Investigator |
KURODA Toshio The Institute of Low Temperature Science, Hokkaido University, 低温科学研究所, 教授 (70080447)
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| Co-Investigator(Kenkyū-buntansha) |
KOUCHI Akira The Institute of Low Temperature Science, Hokkaido University, 低温科学研究所, 助手 (60161866)
FURUKAWA Yoshinori The Institute of Low Temperature Science, Hokkaido University, 低温科学研究所, 助手 (20113623)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Whisker / Ice crystal / Kinetic coefficient / Condensation coefficient / Screw dislocation / らせん転位 / スパイラル成長 |
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| Research Abstract |
Purpose of this study is to investigate an origin of ice whisker and a mechanism of growth of its tip surface ((0001)). The following results were obtained.
1) We made an experimental apparatus for growth of ice whisker from the vapor phase at -80゜C at lowest and for in-situ observation of grawing whisker using a refrigerator LAUDA-SK80D which was bought by this Grant.
2) We succeded in growing ice whisker on (0001)substrate of PBI_2 crystal at -50[[ -70゜C. Its growth direction is c-axis and tip surface is composed of (0001) face.
3) Since a probablity of growth of ice whisker was less than 1%, a necessary condition of ice whisker growth is that screw dislocations intersect only (0001) faces of ice crystals nucleated on PbI_2 substrate.
4) The Growth rates R_<exp> of tip surface were measured as functions of supersaturation<sigma>_<<infinite>> 5) The experimental results were analyzed by taking into account the diffusion process of water molecules and the surface kinetic process for incorporating the molecules into crystal lattice, and it was found that the dependences on surface supersaturation of kinetic coefficient and condensation coefficient were interpreted by spiral growth with the aid of screw dislocations.
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