1991 Fiscal Year Final Research Report Summary
Cutting Tool Materials of Cubic Boron Nitride Single Crystal
| Project/Area Number |
01850020
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
機械材料工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
FUKUNAGA Osamu Faculty of Engineering Tokyo Institute of Technology, Dr. Eng., Professor, 工学部, 教授 (20199251)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Cutting tool / Cubic BN / Single crystal / Solvent grwoth / High pressure growth / Alkali-B-N solvent / Phase boundary / Seeded growth |
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| Research Abstract |
Single crystal cBN has many problem to solve for practical application of cutting tools. In 1987, the reporter's groupe has succeeded to growth single crystal cBN at first time in the world. High pressure high temperature of cBN growth is more difficult than the diamond growth. The basic data for the crystal growth of cBN are lacked. This study covers basic data for cBN growth. cBN cannot grow at non-equiriblium condition, then the stable P-T condition of cBN must be determined by high pressure experiments. We determined phase boundary curve as P=T/200 - 3.5(Gpa, C). It was found that cBN is stable to 700 C at normal pressure.
BN solvents for the crystal growth were selected from alkali and alkali-earth boronnitride. cBN synthesized P-T regions were determined for various solvents-BN systems by high pressure experiments. We found that cBN was synthesized above 4-5 GPa and 100-1200 C. The minimum temperature of cBN synthesis coincides the minimum liquidus line of the system. Growth of cBN, however, was observed at 1700 C or higher temperature. Crystal growth of cBN was carried out using seed crystals of diamond and cBN. We found that cBN film can be grow at 1200-1300 C region. This new finding provides basic technology of cBN grow for the application of cutting tools.
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