J.H. Chen

Effects of conductive polyaniline (PANI) preparation and platinum electrodeposition on electroactivity of methanol oxidation

A modified galvanostatic method, termed the ‘pulse galvanostatic method’ (PGM) was used to synthesize nanofibular polyaniline (PANI). In contrast to granular PANI prepared by the conventional galvanostatic method (GM), nanofibular PANI has better conductivity and higher specific surface area. The nanofibular PANI electrode modified by Pt microparticles, at the same Pt loading, exhibits a considerably higher electrocatalytic activity on the methanol oxidation than that of the granular PANI electrode modified by Pt microparticles. Furthermore, the PGM method can be used as a good method for Pt microparticle electrodeposition. The composite electrode composed of PANI and Pt microparticles has the best electrocatalytic activity in the experimental range. The effects of Pt loading and methanol concentration, on the electrocatalytic activity for methanol oxidation have also been researched.

Preparation and characteristics of oxide films on AA339.1 cast aluminum

Ceramic films on AA339.1 cast aluminum alloys (ANSI) were prepared by high-voltage anodization (HVA) in a mixed electrolyte of glutaric acid, sodium tungstate and phosphoric acid. The characteristics of the films and the effect of various factors, such as peak current density, composition and concentration of the electrolytes, on the properties of the films were investigated in detail. In addition, the structure, chemical composition and morphology of the films were investigated by electron diffraction spectroscopy (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the elements in the film are O, Al, Si, P, S, C and that the structure of the film is non-crystalline. Compared with conventional anodic film on aluminum, the films on AA339.1 show good ornamental property and high microhardness. SEM results indicate that the film appears to be divided into loose and compact layers. Many nano-gaps or cracks are observed in the compact layer, which may be a result of a different film formation mechanism from that of conventional anodic films.

Real-time BAW admittance analysis study of the curing behavior of organic coating layers

Abstract The real-time curing behavior of organic coatings is investigated by bulk acoustic wave (BAW) admittance analysis. During the curing process of the organic coating, multiple processes, such as solvent evaporation, change of the state and mass of coating film, etc., can be described and explained by the change of the parameters of the BAW admittance analysis: f r (frequency of zero phase), Δ L m (inductance variation), R m (resistance) and C s (stray capacitance). Additionally, the effects of the film thickness and solvents on the curing behavior are also investigated.