| RefNo | EC/1988/11 |
| Previous numbers | Cert XXII, 108 |
| Level | Item |
| Title | Evans, Trevor: certificate of election to the Royal Society |
| Date | 1985 |
| Description | Citation typed |
| Citation | Distinguished for contributions to the understanding of the physical properties of diamond. Evans' work has been characterised by technically excellent and elegant experiments, which have produced definitive results and clear understanding in difficult, and (prior to his work) controversial fields. His experiments on etching with gases achieved controlled changes of etch pit orientation of low-index faces. He applied this to diamond thinning and obtained the first transmission electron micrographs, which revealed platelets in natural type I diamonds reported by Raman and Nilakantan (1940). Next he demonstrated diamond plasticity at about 1800 degrees Celsius by bending diamond plates, obtaining quantitative information, and showed that type II diamond (no platelets) could be deformed plastically at lower stresses than type I diamonds (with platelets). Later he subjected diamonds to higher temperatures and pressures and derived the kinetics of the diamond graphite transformation. He showed that the transformation was a 'single atom' process and not a 'group of atoms' process that was then currently in favour. In a recent major advance he developed a high pressure cell capable of heating diamond up to 2800 degrees Celsius under a pressure of 10 Gpa. With this cell he succeeded in aggregating the dispersed nitrogen atoms in synthetic diamonds into the same types of aggregates as are found in natural diamonds (including platelets). He thus produced in the laboratory the aggregation sequence that has occurred in natural diamonds over a geologically extended period, and so succeeded in an endeavour in which workers in the USA and Russia had tried with more limited success. |
| AccessStatus | Closed |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA4022 | Evans; Trevor (1927 - 2010) | 1927 - 2010 |