Structural Characterization, Global and Local Electrochemical Activity of Electroless Ni–P-Multiwalled Carbon Nanotube Composite Coatings on Pipeline Steel

Assessment of the performance of Ni carbon nanotube nano composite coatings and activated carbon for diesel exhaust treatment

Diesel engines are essential in sectors such as transportation, agriculture, and power generation, offering benefits like fuel efficiency, high power output, and durability. However, their emissions (NOX, CO2, CO, HC, SO2, and PM) significantly contribute to air pollution, posing serious environmental and health risks. This study aimed to design and fabricate a unit that simulates diesel engine emissions and tests various purification materials. The unit consists of a combustion chamber, filtration media, and exhaust pipes, with materials such as activated carbon, activated carbon with magnesium oxide, and Ni-Carbon Nanotube (CNTs) nanocomposites tested under controlled combustion conditions to measure their pollutant removal efficiencies. Results showed that 100% activated carbon achieved pollutant removal efficiencies of 85.21% for CO2, 80.77% for CO, and 68.84% for HC. Combining activated carbon with magnesium oxide (AC: MgO) enhanced these efficiencies to 76.92% for CO2, 86.84% for CO, and 73.28% for HC. Ni-CNTs nanocomposites (at 0.2 concentration) demonstrated the highest performance, with removal efficiencies of 93.13% for CO2, 94.87% for CO, and 76.02% for HC. These results emphasize the potential of Ni-CNTs nanocomposites as highly efficient materials for reducing diesel exhaust emissions, contributing significantly to cleaner air, better public health, and more sustainable diesel technologies.

Investigating the Properties of Electrodeposited of Ni-P-ZrC Nanocomposite Coatings

Superior corrosion resistance along with higher mechanical performance is becoming a primary requirement to decrease operational costs in the industries. Nickel-based phosphorus coatings have been reported to show better corrosion resistance properties but suffer from a lack of mechanical strength. Zirconium carbide nanoparticles (ZCNPs) are known for promising hardness and unreactive behavior among variously reported reinforcements. The present study focuses on the synthesis and characterization of novel Ni-P-ZrC nanocomposite coatings developed through the electrodeposition technique. Successful coelectrodeposition of ZCNPs without any observable defects was carried out utilizing a modified Watts bath and optimized conditions. For a clear comparison, structural, surface, mechanical, and electrochemical behaviors of Ni-P and Ni-P-ZrC nanocomposite coatings containing 0.75 g/L ZCNPs were thoroughly investigated. The addition of ZCNPs has a considerable impact on the properties of Ni-P coatings. Enhancement in the mechanical properties (microhardness, nanoindentation, wear, and erosion) is observed due to reinforcement of ZCNPs in the Ni-P matrix, which can be attributed to mainly the dispersion hardening effect. Furthermore, corrosion protection efficiency (PE%) of the Ni-P matrix was enhanced by the incorporation of ZCNPs from 71 to 85.4%. The Ni-P-ZrC nanocomposite coatings provide an exciting option for their utilization in the automotive, electronics, aerospace, oil, and gas industry.

Fabrication of Metal/Carbon Nanotube Composites by Electrochemical Deposition

Metal/carbon nanotube (CNT) composites are promising functional materials due to the various superior properties of CNTs in addition to the characteristics of metals, and consequently, many fabrication processes of these composites have been vigorously researched. In this paper, the fabrication process of metal/CNT composites by electrochemical deposition, including electrodeposition and electroless deposition, are comprehensively reviewed. A general introduction for fabrication of metal/CNT composites using the electrochemical deposition is carried out. The fabrication methods can be classified into three types: (1) composite plating by electrodeposition or electroless deposition, (2) metal coating on CNT by electroless deposition, and (3) electrodeposition using CNT templates, such as CNT sheets and CNT yarns. The performances of each type have been compared and explained especially from the view point of preparation methods. In the cases of (1) composite plating and (2) metal coating on CNTs, homogeneous dispersion of CNTs in electrochemical deposition baths is essential for the formation of metal/CNT composites with homogeneous distribution of CNTs, which leads to high performance composites. In the case of (3) electrodeposition using CNT templates, the electrodeposition of metals not only on the surfaces but also interior of the CNT templates is the key process to fabricate high performance metal/CNT composites.