The effect of prior corrosion on the mechanical properties of 7475-T761 aluminum alloy was investigated by immersion test, stress corrosion test, cathode charge method and electrochemical polarization test. Results show that prior corrosion in the solution with 3 wt% NaCl and 0.5 wt% H 2 O 2 leads to mechanical properties deterioration of 7475-T761 aluminum alloy. Moreover, the elongation decreases significantly. This is mainly attributed to electrochemical corrosion and hydrogen embrittlement, in which corrosion plays a major role. Tensile stress promotes the degradation of the mechanical properties by accelerating the pitting corrosion and hydrogen embrittlement.

I–V characteristics of silicon field emission diode and triode were investigated. The maximum emission current of 17 μA and the lowest onset voltage of 60 V were obtained by an array of 245 silicon tips. The typical reverse recovery time of the diode was 350 ps. The typical transconductance of the triode was about 10−7 S. The fabrication processes for forming sharp silicon conical tips with a gate hole diameter 1 μm smaller than the corresponding oxide mask is described. The results of a high temperature activation process for improving emission characteristics of the device are presented. The stability and uniformity of the devices affected by the fabrication process and emission environment are also discussed in this paper.

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