Experimental and numerical investigation of plain and Ni-reinforced porous alumina ceramics composites produced with agro-waste pore formers

The mechanical and corrosion resistance properties of porous alumina ceramics are of utmost importance in understanding their operational behavior if they are to stand the test of time. Recently, porous alumina systems have been considered suitable for application in wide-ranging industrial processes that require extreme service conditions such as high temperatures and corrosive mediums due to their satisfactory thermal, mechanical and corrosion resistance properties. However, due to the inherent brittleness of ceramics and their high sensitivity to thermo-mechanical loading, large-scale production of porous alumina components for the above applications is constrained. In the present study, the singular effect of different pore formers (rice husk and sugarcane bagasse) as well as the joint effect of these pore formers and nickel (Ni) reinforcement on the mechanical and corrosion resistance of plain and Ni-reinforced porous alumina ceramics composites have been studied respectively. Experimental results showed that the mechanical properties of the plain porous alumina ceramics decreased with rising pore former content (hardness, tensile stress and compressive stress of 529.1-26HV, 20.4-1.5MPa and 179.5-10.9MPa respectively). Moreover, higher mechanical properties were observed in the SCBgraded samples up to the 15wt% PFA mark, while beyond this point, the silica peak present in the RH-graded samples favored their relatively higher value. The corrosion resistance evaluation of the plain porous alumina ceramics showed that the RH and SCB graded samples demonstrated superior corrosion resistance in strong acid and strong alkali mediums respectively. For the Ni-reinforced porous alumina composites, an inverse relationship was established between the mechanical properties and Ni reinforcement. Overall, maximum hardness, tensile stress and compressive stress values of 167.3HV, 12.6MPa and 55.3MPa respectively were exhibited by the RH-graded porous alumina composite reinforced with 2wt% Ni. Relative to the plain porous alumina series, the RH-graded composites exhibited a better corrosion resistance in the corrosive mediums as compared with the SCBgraded counterparts which demonstrated reduced performance in both mediums. Moreover, superior corrosion resistance was observed in the RH-graded porous alumina composite reinforced with 2wt% Ni. The Levenberg Marquardt Back Propagation Artificial Neural Network (LMBP ANN) was deployed as an artificial intelligence model to characterize the plain and Ni-reinforced porous alumina ceramics composites developed in the present study. The inputs of the models developed include the sample formulation and the corroding time while the outputs are the density, porosity, hardness, compressive stress, tensile stress, tensile modulus, mass loss in NaOH and mass loss in H2SO4. The accuracy and performance efficiency of the developed models (ANN I and ANN II) were confirmed by the large coefficient of determinant (≥ 0.95) registered for the plots of all the experimental results against their corresponding LMBP ANN predicted results. A Graphical User Interface was designed to create a user friendly platform that provides users with real time characterization of the plain and Ni-reinforced porous alumina ceramics composites.

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