Modification of polycrystalline nanodiamonds by using periodic magnetic field enhanced hydrogen plasma and the application on nanogrinding of thin film magnetic head

Polycrystalline nanodiamonds (NDs) derived from shock wave synthesis exhibits serious agglomeration in non-polar medium such as clean oil. Here we report an efficient new approach to modify the NDs by exposing the nanoparticles to periodic magnetic field (PMF) enhanced hydrogen plasma in the gas phase. The modification treatment transforms oxygenated groups on the NDs surface into CH terminations. The evolution of polycrystalline NDs has been carefully characterized by FTIR, Raman and XRD analysis and the enhancement mechanism of PMF was discussed. After this treatment, well-dispersed and stable suspensions of diamond nanoparticles in clean oil with average diameter of 74.7 nm can be obtained. Subsequent nanogrinding of thin-film magnetic heads (TFH) validates their dispersion behavior. A smooth substrate (Ra ∼ 0.387 nm) surface and a planar recording surface (PTR ∼ 0.048 nm) were achieved.