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 TiS
2 was present in the scales in addition to TiO
2 and Al
2O
3. 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 Al
2O
3 of the scale was converted to sodium aluminate and dissolved into the salt. And scanning electron micrograph showed that the Al
2O
3 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 Al
2O
3 layer is porous.
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