Study on the Corrosion Characteristics of Sputtered Barrier-Free Cu(MoN) Copper Seed Layers

摘要

The corrosion resistance of NdFeB magnets is improved by direct MoN and Cu(MoN) thin film treatment of a sintered NdFeB magnet surface. X-ray diffraction and transmission electron microscopy are used to examine the microstructure of the thin films. The hardness, wettability, and surface roughness of the thin films are investigated using nanoindentation, contact angle measurements, and atomic force microscopy, respectively. The MoN and Cu(MoN) thin films exhibit a typical amorphous microstructure and a smooth surface with an average roughness of about 2 nm. The results of alternating-current (AC) impedance spectroscopy in 5% NaCl solution show that the AC impedance of the thin films increased with time. The IZ(10) (mHZ) values for MoN (15000 Q/cm(2)), Cu(MoN) (1000 Omega/cm(2)), and uncoated NdFeB magnets (550 Omega/cm(2)) show an 2-fold decrease in the low-frequency impedance due to the Cu-O bonds will be shorter and firmer because of less anti-bonding.