Corrosion Characteristic Analysis of Valve Body Materials for Relay in Ship

Corrosion potentials of 20 steel, 2Cr13, QAl 9-2, QAl 10-3-1.5 and QAl 10-4-4 in NaCl solution, and their galvanic corrosion currents when coupled to QAl 9-2 were tested by electrochemical methods. The surface morphologies of corrosion specimens were examined after the test. The results reveal that the anti-corrosion properties of bronze alloys are better than that of steel. QAl 10-4-4 has the most positive corrosion potential among the bronze alloys which will result in a greater galvanic corrosion to anode QAl 9-2 when they coupled. Both QAl 9-2 and QAl 10-3-1.5 show good anti-galvanic-corrosion property when they coupled with QAl 9-2. The results provide a guideline for the selection of the relay valve material.