Surface modification of AISI 316 steel by α-MoO3 thin films grown using cathodic cage plasma deposition

In recent years, the MoO3 in different morphologies and phases have attracted the attention due to their physical and chemical properties, mainly in the form of thin films. In this paper, we present the growth of thin films of molybdenum trioxide on AISI 316 steel using the cathodic cage plasma deposition (CCPD) technique at low temperature, in fluctuating potential and with variation of the gas flow, argon and oxygen. Our study revealed, for the first time that the films deposited under 50:50 (50 sccm Ar/50 sccm O2) and 80:20 (80 sccm Ar/20 sccm O2) gases composition crystallized in the orthorhombic phase (α-MoO3), without secondary phases and with a thickness of 5 μm and 1 μm, respectively. The 80:20 sample a higher roughness and consequently a larger grain. Vickers microhardness measurements show that low temperature plasma deposition maximizes the surface hardness of AISI 316 austenitic stainless steel (80:20–545 HV/50:50–465 HV/AISI 316–187 HV) with excellent adhesion, classified as HF1, with no cracks or detachment regions, which indicates a good level of plasticity of the films.