Developing a Graphite like Carbon:Niobium thin film on GTD-450 stainless steel substrate

Graphite like Carbon: Niobium (GLC:Nb) thin films with different Nb contents were applied on GTD-450 stainless steel substrates. The microstructure, mechanical properties, friction coefficient and anti-corrosion performance of the coatings were investigated. The outcomes from Raman spectroscopy confirmed the formation of GLC phase. The results from X-ray diffraction (XRD) analysis also endorsed the formation of face center cubic Nb-C phase and by increasing the Nb content, the grain size of this phase increased. The hardness of the coating increased with increasing the Nb content, reaching to the value of similar to 12 GPa for Nb content of similar to 50 at% (N-4). On the contrary, the friction coefficient of the coated substrates decreased by increasing the Nb content. Electrochemical impedance spectroscopy (EIS) measurements depicted a remarkable improvement in the corrosion resistance of the GTD-450 stainless steel substrate coated by GLC:Nb. Altogether, considering the outstanding mechanical and anti-corrosion properties of the coated steel, the GLC:Nb coating can be propounded as an auspicious candidate to be applicable as a heavy-duty protective coating for the metal substrate which is used in harsh environments such as turbine blades.