塩化ナトリウム溶液中におけるアルミニウムの孔食電位と保護電位について (pHの影響)

Abstract

The pitting and protection potentials for pure aluminum in 0.5N NaCl solutions (pH=4, 6, 8, 10, and 12) were investigated by means of an apparatus consisting of a potentiostat and a high sensitive recorder.The results obtained were as follows.The pitting potentials determined by polarization curves of aluminum in 0.5N NaCl solutions (pH=4, 6, and 8) showed two kinds of different values.(1) In the solution of pH=4, the 1st pitting potential was -1.15V (vs. S.C.E.) and the 2nd one was -0.73V (vs.S.C.E.); and the protection potential was -1.20V (vs.S.C.E.).(2) In the solution of pH=6, the 1st pitting potential was -1.16V (vs.S.C.E.) and the 2nd one was -0.72V (vs.S.C.E.); and the protection potential was -1.20V (vs.S.C.E.).(3) In the solution of pH=8, the 1st pitting potential was -1.16V (vs.S.C.E.) and the 2nd one was -0.70V (vs.S.C.E.); and the protection potential was -1.16V (vs.S.C.E).(4) The pitting and protection potentials for aluminum in 0.5N NaCl solution (pH=10) were -0.70V (vs.S.C.E.) and -1.16V (vs.S.C.E.), respectively.(5) The pitting and protection potentials for aluminum in 0.5N NaCl solution (pH=12) were -0.52V (vs.S.C.E.) and -1.89V (vs.S.C.E.), respectively.