摘要
The new carbon nitride films promise to be with superhigh hardness, unique physical and chemical properties, and have important applications in many fields, such as magnetics, electronics and mechanics, because they are suggested to have a larger bulk modulus B than diamond, which arouses scientists all over the world to great interest. However, many experimental efforts to yield this predicted material had failed since Liu reported the stable phase of β-C<sub>3</sub>N<sub>4</sub> and the possibility of synthesis in 1989. Recently, Niu et al. prepared the films containing nano-size β-C<sub>3</sub>N<sub>4</sub> phase grains by laser ablation of graphite
