By immersion method

the corrosion behavior of HT700T alloy in NaCl-KCl-MgCl_2 molten salts with different doses of Al powder inhibitor at 800 ℃ was studied

with immersion time of 200 h

300 h and 400 h. The morphologies and phase composition of the HT700T alloy after corrosion tests were determined by X-ray diffraction(XRD) and scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDS)

and the effect of corrosion inhibitor on corrosion behavior of the HT700T alloy was analyzed. The results showed that

Ni_3Al with face-centred cubic(FCC) structure could be formed on the sample surface by adding Al powder inhibitor after immersion at 800 ℃. When the addition mass fraction of the Al powder inhibitor was 2%

a dense and stable Al_2O_3 film could be formed on the alloy surface. When the addition mass fraction was 10%

the Al diffused inward

resulting in the change of internal elements of the alloy and the formation of protective layer(composed of Al_2O_3

Al-Ni-Fe

Ni-Fe

Ni-Al

Ni-Al-Fe+Cr_2O_3)

of which the depth changed with time(185.8 μm(200 h)

145.66 μm (300 h)

166.02 μm(400 h))

indicating the inhibitor could effectively reduce the corrosion rate of chloride molten salts at 800 ℃.