Issued Patents 1982
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4340568 | Super hard highly pure silicon nitrides and a process and apparatus for producing the same | Toshio Hirai | 1982-07-20 |
| 4312921 | Super hard-highly pure silicon nitrides | Toshio Hirai | 1982-01-26 |
| 4312924 | Super hard highly pure silicon nitrides | Toshio Hirai | 1982-01-26 |