A challenge to succeed the electroplating of nanocomposite Ni–Cr alloy onto porous substrate under ultrasonic waves and from a continuous flow titanium nanofluids

About 97% of the civil plane is constructed from Aluminum alloys inter alia, the removable arm of the landing gear which is making from galvanized steel (GS). Despite its strength and high performance against alkaline corrosion, the surface aspect of the GS was highly porous due to the manufacturing process. In this study, we report the first successful electroplated coating obtained under ultrasonic waves from a continuous-flow fluid containing the precursor metallic cations on relatively big pieces of aeronautic GS. Two main challenges have risen in this work: 1) Homogenous electrodeposition on a porous surface and 2) succeed a protection barrier against corrosion by electroplating a more noble alloy (NiCr) on a less noble layer (Zn). The comparison of GS and coated GS shows that the mixed nano-alloy covers the totality of the active surface of the sample. The optimized finished coating contains 64% of Ni, 23% of Cr and 11% of nanoparticles TiO2. The rest is defined as impurities from the GS and/or from the main electrolyte. According to the laser profilometer measurements, 98% of pores have been crammed. Morphology, crystallinity and chemical bonds nature into the alloy have been also deeply investigated using SEM, XRD and XPS techniques, respectively. The corrosion resistance has been also tested under salty spray (̴ 3,5% NaCl).