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This study examines the high temperature corrosion response and thermal barrier characteristics of BaCeO3. The phase stability and decomposition behaviour of BaCeO3 were studied using TG-DSC analysis. The thermal diffusivity and thermal expansion coefficient were determined using Laser Flash Analysis and Dilatometry techniques. Microhardness of the sintered BaCeO3 was measured using Vickers micro indentation technique whereas the elastic modulus was found using Ultrasonic technique. Corrosion tests were performed on both BaCeO3 coatings and pellet samples in 32 wt% Na2SO4 + 68 wt% V2O5 salt melt at 900ºC, and the corrosion process was analyzed using XRD and SEM-EDS. The main corrosion product found in the samples exposed to 32 wt% Na2SO4 + 68 wt% V2O5 mixture was Ba3V2O8, with small amounts of CeO2 and BaSO4. SEM-EDS examination of the corroded samples highlighted the significant corrosive action on BaCeO3, indicating the acidic leaching of Ba2+ ions, which then reacted with the salt mixture. The formation of NaVO3 intensified atomic mobility, aggravating the corrosion process. Comparing the hot corrosion of BaCeO3 in pure Na2SO4 and V2O5 melts with that in the 32 wt% Na2SO4 + 68 wt% V2O5 mixture confirmed this effect. No discernible peaks corresponding to any Ce-V-O compound were observed in any of the corrosion patterns, suggesting a preference for BaO over CeO2 in the corrosion process due to its stronger basic nature.

The present investigation deals with development of AA2219 composites with different weight fractions of Cerium oxide (CeO2) reinforcement and characterizing the microstructure and mechanical properties thereof. XRD and SEM micrograph confirm the presence of CeO2 particles and Al2Cu precipitate. The grain size of 0, 0.5, 1.0, 1.5 and 2 wt% CeO2 composites are 483, 453, 411, 362 and 328 μm, respectively. Addition of CeO2 significantly reduces the dendritic morphology and refines the α-Al grain structure. 2 wt% CeO2 addition has yielded the maximum hardness of 124 HV and yield strength of 87 MPa in all the composites developed. Additionally, the developed composites were evaluated by examining the wear characteristics with the co-efficient of friction (COF) and the specific wear rate. In this study, Taguchi's L25 orthogonal array was used to optimize the parameters like reinforcement fraction, load and sliding distance. Signal-to-noise ratio (S/N ratio) and analysis of variance (ANOVA) are used to obtain the parameters highly influencing the wear behaviour. Adhesive wear is exhibited by ploughing at lower loads and delamination is observed with increasing load. Deep shallow ploughs with embarked abrasion are observed at higher loads.

The corrosion behaviour of Mg–6Al–1Zn + XCe (where X = 0.5, 1.0, 1.5 and 2.0 wt% Ce) alloys, aged for 18 h at different temperatures of 180 °C, 200 °C, 220 °C and 240 °C, was studied in 3.5 wt% NaCl solution. The salt spray test was conducted in accordance with ASTM-B117 standard (fog test). The corrosion morphologies, corrosion rate and the composition of the corrosion products were investigated by X-ray Diffraction (XRD), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. The results show the cerium addition and ageing treatment has significantly influenced the corrosion morphologies and the corrosion rate. In AZ61 alloy, the intermetallic β (Mg17Al12) phase acts as a corrosion barrier and upon ageing the Al4Ce phase precipitates along the α grain boundaries. The precipitation modifies the β phase to form more continuous network which subsequently reduces the corrosion attack in the chlorine environment. Salt spray test result shows the AZ61 alloy with 1.5 wt% Ce aged at 220 °C exhibits the better corrosion resistance.

The corrosion behavior of cast Mg–6Al–1Zn + XCa (Where X = 0.5,1.0,1.5 and 2.0 wt.% Ca) magnesium alloy, aged at different temperatures of 180 °C, 200 °C, 220 °C and 240 °C was investigated in accelerated corrosion test chamber according to ASTM-B117 Standard (salt spray test). The exposed alloys were characterized by X-Ray Diffraction (XRD), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. The microstructural refinement due to calcium addition and ageing treatment results in the improvement of corrosion resistance of the experimental alloy. Corrosion rate decreases due to fine precipitation of the β (Mg17Al12) phase distributed along the α-grain boundaries during ageing. Intermetallic phases act as a barrier, which makes the alloy more resistant to corrosion. Results found that better corrosion resistance of the alloy was observed in Mg–6Al–1Zn + 1.5 wt.% Ca with 180 °C ageing temperature. The corrosion behavior of Mg–6Al–1Zn + XCa alloy exhibited by ASTM B117 salt spray testing and electrochemical polarization measurements showed similar trends concluding that the calcium addition and ageing temperature decreases the corrosion rate.