Microstructure, magnetic properties and corrosion resistance of Co-DLC nanocomposite film controlled by substrate temperature

Co-Diamond Like Carbon (Co-DLC) nanocomposite film is considered as a potential biosensor material owing to its various properties such as corrosion resistance and superparamagnetic property. In this work, by adjusting the substrate temperature from 298 to 673 K, the microstructure of Co-DLC nanocomposite film is modulated. With the rising of the substrate temperature, Co particle size increases from 3.8 to 6.4 nm and the crystallinity is improved; the sp(2)/sp(3) ratio of the film is increased, which reduces micropores for penetration of corrosive entities. As a result, the saturation magnetization of superparamagnetic property is enhanced by 2.4 times from 0.11 to 0.26 T, and the total corrosion resistance of the film is enhanced by more than 300 times from 3.5 x 10(4) to 1.1 x 107 Omega center dot cm(2). By establishing the mechanism model, the improvement of magnetic properties and corrosion resistance caused by microstructure controlling in Co-DLC nanocomposite film is reasonably explained.