The corrosion behavior of metal materials in soil environments has been intensively studied recently.

The coated electrodes with high heat resistant alloy materials can considerably improve the efficiency of electrical discharge machining (EDM) process. In the present study, the influence of Aluminum Chromium Nickel Coated aluminium electrode was investigated on the quality criteria using EDM while machining Titanium alloy (Ti -6Al-4V). The peak current, gap voltage and pulse-on time were used as input parameters to analyze the material removal rate, tool wear rate and surface roughness under the L16 based Taguchi method and ANOVA method. It was observed that Aluminum Chromium Nickel (AlCrNi) coated electrode could produce higher material removal rate (MRR), lower of tool wear rate (TWR) and surface roughness (Ra) than uncoated electrode. Compared with EDM with uncoated electrodes, the quality indicators in EDM with coated electrode are better, namely 8% higher MRR, the lower TWR and Ra are 8% and 24%, respectively. The better surface finish was also observed with the coated electrode due to its thermal conductivity.

The electrochemical corrosion behavior of a silver-plated circuit board (PCB-ImAg) in a polluted marine atmosphere environment (Qingdao in China) is studied through a simulated experiment. The morphologies of PCB-ImAg show some micropores on the surface that act as the corrosion-active points in the tests. Cl− mainly induces microporous corrosion, whereas SO2 causes general corrosion. Notably, the silver color changes significantly under SO2 influence. EIS results show that the initial charge transfer resistance in the test containing SO2 and Cl− is 9.847 × 103, while it is 3.701 × 104 in the test containing Cl− only, which demonstrates that corrosion accelerates in a mixed atmosphere. Polarization curves further show that corrosion potential is lower in mixed solutions (between −0.397 V SCE and −0.214 V SCE) than it in the solution containing Cl− only (−0.168 V SCE), indicating that corrosion tendency increases with increased HSO3− concentration.