Authors: Min Kang, Eun Duck Park, Jae Eui Yie
Abstract: The effect of a microwave-enhanced wet chemical etching process of SiC particles on the
electroless copper plating and on the Al/Cu-coated SiC composites was investigated. The
microwave-enhanced wet etching process increased the concentration of surface oxides on SiC. The
BET surface area of SiC increased, reached its maximum value at 30 s, and then decreased during an
etching process. The enhanced chemical adhesion strength between the coated copper and SiC was
observed after an etching process. Furthermore, the sintering density and transverse rupture strength
(TRS) of Al/Cu-coated SiC composites were improved when SiC particles were etched. This result
indicated that the microwave-enhanced etching of SiC particles also improved chemical and
mechanical adhesion of Al/Cu-coated SiC composites.
1145
Authors: Gue Serb Cho, Jung Kyu Lim, Kyeong Hwan Choe, Won Sik Lee
Abstract: CNTs were decorated with Ni nanoparticles to decrease floatation of CNTs and improve the wettability between CNT and Al melt by electroless plating method. The as-received size of multi-wall CNTs with 99.5% purity was 10~20nm in diameter and 20um in length. Before Ni deposition, the wet ball milling was tried to improve the dispersion of CNTs in the Ni sulfate solution for several hours. After wet ball milling, the Ni electroless platings have been performed for 1hours at electroless deposition temperature. The Ni deposited CNTs have been characterized in respect of dispersion and size changes of CNTs and Ni particles with field emission scanning electron microscopy(FESEM). The deposited Ni nanoparticles onto the CNTs were 50nm in diameter without ball milling, but they increased in size with increasing milling times up to 120nm. Also, the milled CNTs were damaged and changed from its original morphology due to the high ball milling energy. The addition of surfactant improved the distribution and spheroidization of precipitated Ni nanoparticles. From this study, the multi-wall CNTs have been deposited and decorated with spherical Ni nanoparticles by electroless deposition at a proper milling time and surfactant addition.
360
Authors: Wan Chang Sun, Ming Feng Tan, Jian Hua Lu, Lei Zhang, Quan Zhou
Abstract: Electroless Ni-P and Ni-P-Al2O3 composite coatings on low carbon steel (Q235) sheets were prepared by adopting optimum plating process. The cross-section morphology and structure as well as the phase transformation of the composite coatings were studied by scanning electron microscopy(SEM), X-ray diffraction(XRD). It was shown that the Al2O3 particles homogeneously dispersed in the entire Ni-P film matrix, and the structure of Ni-P-Al2O3 composite coatings as deposited was amorphous. The corrosion behaviors were evaluated by electrochemical tests. The experimental results indicated that the corrosion resistance of Ni-P-Al2O3 coatings was superior to Ni-P coatings due to the effect of Al2O3 particles. In addition, the oxidation resistance test, which was carried out by using oxidation weight method, showed that ternary Ni-P-Al2O3 composite coating had a better oxidation resistance than Ni-P coating.
831
Authors: Ming Feng Tan, Wan Chang Sun, Lei Zhang, Quan Zhou, Jin Ding
Abstract: Electroless Ni-P coating containing ZrO2 particles was successfully co-deposited on low carbon steel substrate. The surface and cross-sectional micrographs of the composite coatings were observed with scanning electron microscopy (SEM). And the chemical composition of the coating was analyzed with energy dispersive spectroscopy (EDS). The oxidation resistance was evaluated by weight gains during high temperature oxidation test. The results showed that the embedded ZrO2 particles with irregular shape uniformly distributed in the entire Ni-P matrix, and the coating showed a good adhesion to the substrate. The weight gain curves of Ni-P-ZrO2 composite coatings and Ni-P coating at 923K oxidation experiments were in accordance with . The ZrO2 particles in Ni-P matrix could significantly enhance the high temperature oxidation resistance of the carbon steel substrate as compared to pure Ni-P coating.
569
Authors: Su Min Zhou, Wei Huang, Shi Ming Shen
Abstract: Alygorskite is a kind of hydrated magnesium aluminium silicate clay mineral. A novel linear core-shell structured Ni-P coated micro-fiber palygorskite (MFP) was fabricated via an electroless plating process in acid bath. The composition, morphology and structure of the as-prepared products were characterized by the techniques such as powder X-ray diffra-ction (XRD), energy-dispersive X-ray spectrum (EDS), and scanning electron microscopy (SEM). The Magnetic Property of the powders was conducted from a vibrating sample magnetometer (VSM). It was observed that the MFPs surface was compactly coated with irregular Ni-P particle. The XRD patterns indicate the amorphous Ni-P microstructure of coating. Magnetic properties show that coated MFPs are ferromagnetic materials. The satura-tion magnetization (σs) and coercivity (jHc) of the powders are 13.86emu/g and 43.97 Oe respectively.
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