Epoxy formulations containing 1%, 3%, and 5% SiO2 nanoparticles (SNPs) were produced and applied to mild steel substrates in order to improve their thermal, nanomechanical, and abrasion resistance. Field emission scanning electron microscopy (FE-SEM) was used to analyze the dispersion of nanoparticles in the final coating samples, and Energy-dispersive X-ray spectroscopy (EDX) was used to confirm the presence of nanoparticles. Thermogravimetric analysis (TGA) was employed to measure the thermal resistance of the prepared coatings. Conventional techniques were used to measure the impact and scratch resistance. For nanomechanical testing, nanoindentation was performed using a Berkovich-type indenter. Using a taber abraser, the abrasion properties of the coatings were measured. The FE-SEM images indicated good dispersion of the nanoparticles at all three different loading levels. The scratch, impact, and hardness of coatings improved with the addition of the SNPs. Nanomechanical properties, such as hardness and elastic modulus, improved when compared to the unmodified coatings. The thermal and abrasion resistances of the coatings improved with the increase in the SNPs content of the coatings. The highest mechanical, thermal, and abrasion properties were obtained for the coatings with 5% SNP content.
Epoxy coating formulations containing 1%, 3%, and 5% SiO2 nanoparticles were produced and applied on a mild steel substrate to achieve the objective of high performance corrosion resistance. The electrochemical impedance spectroscopy (EIS) technique was employed to measure the anticorrosive properties of coatings. The corrosion tests were performed by exposing the coated samples in a solution of 3.5% NaCl for different periods of time, varied from 1 h and up to 30 days. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analyses revealed the presence of nanoparticles in the final cured samples. Establishing the incorporation of the nanoparticles in the coating formulations was confirmed by employing both of XRD and FT-IR techniques. The FT-IR spectra have proved to be satisfactory indicating that there was a complete reaction between the epoxy resin with the hardener. EIS measurements confirmed that the presence and the increase of SiO2 nanoparticles greatly improved the corrosion resistance of the epoxy coating. The highest corrosion resistance for the coatings was obtained for the formulation with 5% SiO2 nanoparticles content, particularly with prolonging the immersion time to 30 days.
This study is focuses on the investigation of the effect of using TiO2 short nanofibers as a reinforcement of an Al matrix on the corrosion characteristics of the produced nanocomposites. The TiO2 ceramic nanofibers used were synthesized via electrospinning by sol-gel process, then calcinated at a high temperature to evaporate the residual polymers. The fabricated nanocomposites contain 0, 1, 3 and 5 wt.% of synthesized ceramic nanofibers (TiO2). Powder mixtures were mixed for 1 h via high-energy ball milling in a vacuum atmosphere before being inductively sintered through a high-frequency induction furnace at 560 °C for 6 min. The microstructure of the fabricated samples was studied by optical microscope and field emission scanning electron microscope (FESEM) before and after corrosion studies. Corrosion behavior of the sintered samples was evaluated by both electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PPT) in 3.5% NaCl solution for one hour and 24-h immersion times. The results show that even though the percentage of ceramic nanofibers added negatively control corrosion resistance, it is still possible to increase resistance against corrosion for the fabricated nanocomposite by more than 75% in the longer exposure time periods.
Synergistic formulations were developed with nano-pigments, and their effects on the mechanical properties on steel substrates and structures were evaluated. This paper provides a complete analysis of the epoxy coating, focusing on the incorporation of nano-pigments and their synergistic effects in obtaining higher mechanical properties. This study reports the preparation of epoxy nano-silica composites, their characterization, and the development of coatings based on nano-silica and ZnO particles. In this composite, epoxy resin was incorporated with SiO2 as the main pigment and ZnO as a synergistic pigment to achieve high-performance epoxy coatings for multiple applications. The mechanical properties of these coatings (ESZ1–ESZ3) were evaluated by nanoindentation, and were used to measure the enhanced durability of nanocomposite coatings developed with synergistic formulations with different types of nanoparticles. Their performance was evaluated before and after exposure to a 3.5% NaCl solution to examine the changes of hardness and elastic modulus. The results showed that the nanoindentation technique, in conjunction with Fourier transform infrared spectroscopy and X-ray diffraction, could examine the durability and predict the service life of nanocomposite coatings. A correlation was observed between the modulus and hardness before and after exposing epoxy composite coatings (ESZ1–ESZ3) to a 3.5% NaCl solution.
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