Effects of diamond-like carbon film on the corrosion behavior of NdFeB permanent magnet

A diamond-like carbon (DLC) film is deposited on the NdFeB permanent magnet by plasma immersion ion implantation and deposition (PIII&D) and characterized by atomic force microscopy, scanning electron microscopy, Raman scattering, and mechanical tests. Electrochemical and immersion tests conducted for different time durations show that the corrosion resistance in 3.5% NaCl and 5 mM H2SO4 is improved by the DLC coating and corrosion tests also reveal enhanced corrosion resistance in both media. The corrosion mechanism of both the untreated and DLC-coated NdFeB is proposed and discussed.