Figure 4

Measured 488 nm Raman spectra of 300 nm thick NCD layers on ZIRLO tubes, as deposited and after 6, 15 and 30 days of exposure to hot water at 360 °C. The 1332 cm⁻¹ peak is typical of diamond. The broad band visible at 1400–1550 cm⁻¹ is a signature of amorphous carbon located within the grain boundaries, the band at ~1580 cm⁻¹ was assigned to graphite, and the ~1620 cm⁻¹ peak was attributed to the presence of “graphite-like” disordered carbon.