The processing techniques, microstructural characteristics, and erosion corrosion behaviour of Cr₃C₂–NiCr and tungsten carbide (WC)-based cermet coatings are reviewed in this work. Conventional and nanocrystalline Cr₃C₂–NiCr and WC-based cermet coatings are generally synthesized using thermal spray technique. The wear, erosion, and corrosion protection ability of conventional and nanocermet coatings are compared based on available literature. In Cr₃C₂–NiCr coatings, the corrosion resistance is offered by NiCr metal matrix while the wear resistance is provided by the carbide ceramic phase, making it suitable for erosion–corrosion protection. The nanocrystalline cermet coatings exhibits better erosion–corrosion resistance as compared to the conventional coatings. The nanocrystalline coatings reduces the erosion–corrosion rate significantly compared to conventional coatings. It is attributed to the presence of the protective NiCr metallic binder that allows easier and faster re-passivation when the coating is subjected to wear and the fine-grain structure with homogeneous distribution of the skeleton network of hard carbide phases. In addition, corrosion-accelerated erosion dominates the reaction mechanism of erosion–corrosion and, therefore, higher hardness, strength, and better wear resistance of nanocermet coating along with its faster repassivation kinetics accounts for improved corrosion resistance as compared to conventional coatings.

Surface treatment of metallic implants plays a crucial role in orthopedics and orthodontics. Metallic implants produce side-effects such as physical, chemical/electro-chemical irritations, oligodynamic/catalytic and carcinogenic effects. These effects cause bacterial infections and account for huge medical expenses. Treatment for these infections comprises repeated radical debridement, replacement of the implant device and intravenous or oral injection antibiotics. Infection is due to the presence of bacteria in the patient or the surrounding environment. The antibiotic-based medication prevents prophylaxis against bacterial colonization, which is an emphatic method that may otherwise be catastrophic to a patient. Therefore, preventive measures are essential. A coating process was developed with its drug infusion and effect opposing biofilms. Modification in the medical implant surface reduces the adhesion of bacterial and biofilms, the reason behind bacterial attachment. Other polymer-based and nanoparticle-based carriers are used to resolve implant infections. Therefore, using an implant coating is a better approach to prevent infection due to biofilm.

The corrosion behaviour of AlSi10Mg alloy produced by selective laser melting (SLM) under two different atmospheres, namely argon and nitrogen, was compared to that of AlSi10Mg alloy that had been cast. The present study demonstrates the systematic electrochemical behaviour of selective-laser-melted (SLMed) AlSi10Mg. Potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behaviour, illustrating the degrading features of SLMed AlSi10Mg alloy in 0.1 M NaCl solution. The corrosion resistance of AlSi10Mg produced using selective laser melting was found to be 2–3 times greater than that of AlSi10Mg that had been cast. The degradation behaviour was also explained by SEM analysis of the corroded samples of SLMed AlSi10Mg and as-cast AlSi10Mg alloy. It may be deduced that the better corrosion resistance of AlSi10Mg produced through selective laser melting is due to the fast cooling rate associated with the solidification of AlSi10Mg alloy fabricated through selective laser melting, compared with the slow cooling rate associated with the solidification of AlSi10Mg produced by casting.

Zirconium alloy has been extensively used as a cladding material in nuclear power reactors due to its low neutron absorption cross section, excellent mechanical properties, and corrosion resistance. The influence of the swaging parameter, feed rate (0.7, 1.25, 2 m/min) on residual stress induced in Zr-4 alloy is investigated in the present work. A three-dimensional finite element model was implemented in the Deform 3D software to simulate the rotary swaging (RS) process over a circular rod of Zr-4 alloy. The simulation results based on the 3D framework provide a detailed insight of residual stress, true stress versus true strain and force applied over the rod during the multiple pass swaging process; the results are compared with experimental results. The experimental hole drilling method is used to determine the residual stresses on swaged zirconium alloy at different feed rates (0.7, 1.25, and 2 m/min). A similar trend of residual stress between experimental and numerical results from the surface to the center on the swaged rod samples is observed. The same magnitude of residual stress at the surface of the swaged Zr-4 rod is also observed. It is found to be compressive at the surface and tensile in the center of the samples, as observed in the present work.