Impact Synthesis of Carbon Nitride Diamond-like Phases in a Supercritical Fluid

The influence of intense nanosecond laser pulses on structural transformations at the interface of the nanocolumnar carbon nitride film in a supercritical fluid is investigated. The pulse intensity was varied in the range 4.7–12 mJ, while the irradiation time was 5 min. The intensive laser irradiation is known to create shock waves turning liquid into a supercritical fluid. When the intensity exceeds a threshold, some microcrystals of regular shape are formed on the film surface. SEM revealed microcrystals of about 1μm. Photoemission spectroscopy provided the relative amounts of carbon and nitrogen in microcrystals, which are similar to those in the superhard C
3
N
2
and C
2
N compounds.