Characterization of TiN coatings on the plasma nitrided spheroidal graphitic cast iron substrates

The duplex treatment of plasma nitridation and TiN film coating was performed on the spheroidal graphitic (SG) cast iron. The adhesion between the TiN coatings and the SG cast iron substrate was found to increase by nitriding the substrate surface prior to the TiN coating. Dependence of the adhesion on the surface roughness and the microstructure of the nitrided layer as well as on the formation of the γ′-Fe4N compound layer was investigated.