Steel bar corrosion monitoring is a very important part of structure health monitoring and full-life design in civil engineering. Many electrochemical methods have been developed in the last decades for corrosion research, but for field corrosion, pulse perturbation is the fast method. The corrosion of Q235 carbon steel in cement mortar has been researched by potentiostatic pulse method. The solution resistance Rs, the polarization resistance Rp, capacity of double layer and time constant have got by cure fitting. The amplitude of voltage perturbation affected the accurate of result little. The polarization resistance decreases with increasing temperature.

Large-sized Fe-based ODS (Oxide Dispersive Strengthen) high-temperature alloy sheets were successfully synthesized by EBPVD (Electron Beam Physical Vapor Deposition) technique. The sheets were about 120μm thick, and having a diameter of 1000mm, whose surface roughness was less than 1μm (Ra<1μm). The microstructures were examined by SEM (Scanning Electron Microscope). The grain size was 1-4μm. When the substrate temperature was 600°C, the sheet had sharp irregular polyhedral grain, and when the substrate temperature was 700°C the sheet had quite regular grains. The morphological orientation angle increased with the distance from the center of the sheet. During the first period of deposition, the sheet was growing in a G-L-S mode, which corresponded with the corn-like microstructure in the cross-section. While during the final period, the sheet changed into a G-S growing mode, which corresponded to the smooth columnar microstructure.

Large-size Ni-based alloy sheet was prepared by electron beam physical vapor deposition (EB-PVD). Thickness uniformity of large-size sheet for application is important. Based on the Knudsen’s cosine law and the character of the evaporation during EB-PVD, thickness distribution model of condensate on rotary substrate by EB-PVD was established. The thickness model is not consistent with the traditional cosine law, but cosnθ relationship, n=5.3 in this paper. The predicted data of thickness model agrees well with the measured data. The thickness distribution model is not limited to specific vapor source material, therefore, it provides significant insight on the thickness distribution profile for film, coating and sheet deposited on the rotary substrate by EB-PVD.

Large scale Ni-based alloy sheets are prepared by electron beam physical vapor deposition with and without tungsten added into melting pools respectively. Addition W increased vapor rate and decreased compositional transformation during deposition. Chemical constitution of the sheet prepared through tungsten is more similar to that of the ingot. Microstructure of two alloy sheets is observed by scanning electron microscope (SEM) and atom force microscope (AFM). The results show that both of the sheets consist of columnar grains, whose major axes are almost parallel to the normal direction of the sheet. However, the average diameter of grains of the sheet through tungsten is larger than that of the sheet not through tungsten in minor axis direction. Mechanical properties and failure mechanisms of both sheets are studied. Tensile tests are conducted on a number of specimens. Strength, strain-to-failure are estimated under loading condition. The results show that the sheet prepared by EB-PVD through tungsten has a superior strength and an elongation percentage than that of the one prepared without tungsten.

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