Abstract This work aim to investigate the effect of sintering temperature on microhardness and tribological properties of novel equi-atomic TiAlMoSiW HEA fabricated via spark plasma sintering. The influence of Spark plasma sintering temperature on morphological evolution and phase formation was also investigated. The microstructure and the phases formed for the developed HEA were examined using scanning electron microscopy (SEM) and X-ray diffractometry (XRD) respectively. The microhardness and tribological properties were studied using a diamond base microhardness tester Rtec tribometer. It was noticed that sintering temperature has an effect on microhardness and tribological properties. Phase analysis of the samples displayed that the alloy exhibited a bcc matrix with secondary phase precipitate of ordered fcc TiSi 2 phase. The developed HEA showed improved mechanical properties as the sintering temperature increases.
Enhancing mild steel properties is necessary to meet global competiveness and performance during application. In this study, we report the effect of Solanum tuberosum as additive to Zn-TiO2 sulphate bath coating by electrodeposition method on low carbon steel. The interfacial and structural characteristics of the produced coating were examined by means of scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS). The corrosion resistance properties of the deposited coatings were assessed in 3.65% NaCl using linear polarization method and characterized by optical microscope (OPM). Diamond based microhardness tester was used to measure hardness of the composites. From the results, it is evident that Zn-TiO2-solanum coating resulted in improved performance as compared to Zn-TiO2 coating; both in hardness properties and corrosion resistance properties propagation as a result of its embedded structural build up.
Low carbon steel is widely used in engineering applications due to its availability, physical properties and reasonable cost. Regardless of the massive use of mild steel in engineering applications, their application is limited to high tribology and corrosive environment are limited due to low corrosion resistance properties, low microhardness and poor tribological properties. The increase in service life and exceptional properties of reinforcement composite coatings for advanced engineering application has attracted many researchers world-wide. In this study, the effect of manganese oxide (MnO2) on Zn-MgO chloride bath coating by co-deposition route on mild steel is studied. The coating micrographs and surface thickness were examined by means of scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) and PosiTector (SPG) respectively. The thermal stability of the synthesized composite coatings studied in isothermal furnace at 350°C. The findings of the studies are discussed in this paper.
The incorporation of composite and eco-friendly particles or fluids to develop new engineering materials has recently changed the coating world.In this study, a Zn-TiO2-TiB2 ternary alloy was produced from a sulphate bath on a mild steel substrate.Solanum tuberosum (ST) was later introduced to the bath to evaluate the effect of the organic additive on the ternary alloy.The study was conducted under constant plating time and current density.The fabricated matrix was systematically investigated using scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS) for structural properties.The micro hardness and anti-corrosion properties of the deposits were studied using, respectively, a diamond base micro hardness tester and potentiodynamic polarization method.The anti-wear properties and thermal stability of the electrodeposited alloy were studied using a MTR-300 abrasive tester and an isothermal furnace at 250 ºC.From the observed result, the coatings presented good stability, especially for Zn-TiO2-TiB2-ST, as compared to the Zn-TiO2-TiB2 coating.The addition of ST improved the hardness properties of the matrix from 182.4 to197.2HV, and the corrosion rate from 0.9805 to 0.7711 mm/yr.This work established that codeposition of mild steel with TiO2/TiB2/ST is promising in anti-wear and corrosion resistance properties.
Abstract The need for new advanced high temperature materials is in high demand. High Entropy Alloy (HEAs) has been described to possess excellent mechanical oxidation and good corrosion resistance properties even far above the ambient temperature. Attempts are made in this research to study the corrosion, oxidation, microhardness and densification properties of Al 15 Ti 30 Si 30 Mo 15 Ni 10 HEA produced by spark plasma sintering (SPS) for high temperature applications. In addition, the effects of SPS temperature (800, 900 and 1000°C) on the microstructure and phase formation of the developed HEA were reported. The microstructural modification and phases present were examined using the scanning electron microscope (SEM) equipped with the energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD) respectively. Ordered FCC and BCC systems were identified along with clearly defined crystal lattice along with Mo, Ti and Si rich regions were observed. No pores or cracks were observed from the microstructures. Densification of 98.8% accompanied with microhardness of 1445.29HV was achieved for both HEA at 1000°C. The Al 15 Ti 30 Si 30 Mo 15 Ni 10 HEA fabricated at 1000°C displayed a higher polarization value of 3477 Ω.
The development of reinforced composite coating has resulted into advanced engineering application because of the exceptional properties and increase service life. In this study, we investigated the effect of Solanum tuberosum (ST) as additive to Zn-TiO2/Zn-TiB2 sulphate bath coating by co-deposition route on mild steel. The structural characteristics and surface profile of the produced coating were examined using scanning electron microscope coupled with energy dispersive spectroscopy (SEM/EDS) and PosiTector (SPG) respectively. The anti-corrosion resistance activities of the deposited coatings were evaluated on a 101 AUTOLAB potentiostat/galvanostat device in a 3.65 wt% NaCl. The wear characteristics of the Zn-TiO2/TiB2 composite coatings were examined on a dry abrasive MTR-300 test rig. The thermal stability of the produced coatings was studied in an isothermal furnace at 600 °C and further characterized using a high tech optical microscope. From the results, it was found that Zn-TiO2/Zn-TiB2 were compassed with needle like pattern and perhaps a compact and distinctive structure was found with Zn-TiO2/Zn-TiB2/ST coatings. The microhardness deposited coatings increased with TiO2 and TiB2 interference in the plating bath, more significant improvement was noticed in the presence of natural bath-additive and the addition of ST lead to changes in the morphologies of the composite coatings. A massive decrease in corrosion and wear rate in all coatings produced as against the control sample was noticed. This was attributed to the dispersive strengthening activities of the embedded TiO2/TiB2/ST additive on the bath formed.
Abstract The increasing use of mild steel in diverse environments and under different conditions requires the increased interest in research into these groups of specific steels with attention to their moderate corrosion rate and performance. The electrochemical study of Ni-Cr 2 O 3 /SnO 2 coating was studied using potentiodynamic techniques. The microhardness properties of the deposits were studied using Emco microhardness tester. The effect of Cr 2 O 3 /SnO 2 on nickel-based coatings was investigated to analyze the corrosion resistance of the coating by using the polarization method. The result indicates a reduction in corrosion rate with the addition of Cr 2 O 3 /SnO 2 and the hardness of the coated sample also reduced drastically with the addition of SnO 2 to the bath.
High entropy alloy developed with spark plasma sintering was modelled with COMSOL Multiphysics. This focus at examining the effect of spark plasma sintering fabrication parameters on thermal and mechanical stress distribution in the sintered Al 20 Cr 20 Fe 25 Ni 25 Mn 10 high entropy alloy (HEA). And to achieve this, a fully thermal-electrical-mechanical integrated and dynamic finite element model (FEM) was adopted. The simulation utilised the optimal parameters employed in the laboratory to produce the samples. The geometry for the modelling was 2D axisymmetric as the parameters were based on temperature-dependent characteristics noting that only the sintered sample was modelled and simulated in order not to simplify the modelling. The FEM maintained constant sintering temperature, pressure, and heating rate but concentrated on the impact of residence durations. To verify the simulation results, morphological alterations and densification validation tests were conducted. The microstructural characterization of the sintered sample demonstrated the relationship between the stress distribution and computational temperature found in the current FEM. Noting good particle-to-particle necking. From the model, results showed that the sintered sample at different points depicted a yield stress far greater than the von Mises stress with least thermal stress at 30 MPa. This validate that the developed sample is mechanically stable based on the factor of safety failure criterion and design. However, the study recommend that further work should be conducted considering different sintering pressure of variation 10 to 30 MPa.
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