人工海水中の塩によるTiAlの高温腐食挙動
1997 年 46 巻 2 号 p. 83-89
詳細
1997 年 46 巻 2 号 p. 83-89
Hot corrosion behaviour of a TiAl which was applied with salt in an artificial sea-water was examined. Specimens were immersed in an artificial sea-water, water was evaporated and then hot corrosion tests were performed at 973-1273K for 18-144ks.
The depths of corrosion loss in the salt-applied specimens were higher than those of the salt-free specimens. A linear relationship between the reaction rate constant and reciprocal of absolute temperature was obtained in the test of salt-free specimens but it was not obtained in the test of salt-applied specimens. X-ray diffraction analysis showed that TiS2 was present in the scales in addition to TiO2 and Al2O3. High quantity of Al and high pH value were detected in the solution obtained by hot-water extraction of a specimen after hot corrosion. Therefore, it was considered that part of Al2O3 of the scale was converted to sodium aluminate and dissolved into the salt. And scanning electron micrograph showed that the Al2O3 layer in the scale was highly porous.
It is thought that the hot crrosion of TiAl under application of the salt in the artificial sea-water is accelerated because the formed Al2O3 layer is porous.
