Search

The electroformed copper with various microstructures are fabricated under conditions of non-agitation and ultrasonic agitation according to the demand of the electroforming micro components. The microstructure of the electroformed copper layer was observed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The preferred orientations of the layer were characterized by X-ray diffraction (XRD). The tensile strength was evaluated with a tensile tester. It was found that the copper layer preferentially grow along the (220) plane during the electroforming process, and the ultrasound-assisted technique led to a highly preferred orientation. The effects of ultrasonic vibration increased the chance of nucleation and controlled the excessive growth of copper grains during electroforming process. The microstructure of copper electroformed under condition of ultrasonic agitation is made up of regular columnar crystals, and its tensile strength increased by 40% in comparison with that of under condition of stationary state. [ABSTRACT FROM AUTHOR]

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively. [ABSTRACT FROM AUTHOR]

Black and gray microarc oxidation coatings have been obtained on 2A70 Aluminum alloy in phosphate electrolyte with and without titania sol, respectively. The growth process of the microarc oxidation coating in the electrolyte with titania sol was investigated. The coating was characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray. The coating thickness was measured by eddy current thickness meter. The results show that the titania sol increase the growth rate of microarc oxidation coating. In both cases the composition of coatings contain Al and O, and are mainly composed of γ-Al2O3 and AlPO4. Compared with the gray coating, large amount of Ti is found on the surface of black coating. The titania sol added in the electrolyte results in Ti in the coating, in the form of TiO and Al2TiO5. [ABSTRACT FROM AUTHOR]