In order to determine the optimum ratio of the iron and silicon content in commercial 2 S aluminium to be used for reactor applications, corrosion test has been carried out in distilled water kept at high temperatures between 120° and 300°C in steel autocrave. Pyrex glass reservoir with pyrex lid was used to prevent water from being contaminated by iron ion coming from steel. The glass reservoir contains specimens hanged one by one by cotton string no more resist the attack of water, specimens were heaped with photographic dry plate glass pieces between them.
Weight change of the specimen was measured, an example of which is shown in Fig. 13 a), b), and c). The outlook of the specimens attacked by water at the respective elevated temperatures are shown in Fig. 1-12 photographs. Both results are summarized into Fig. 14, where the numbers of the specimens which showed best corrosion resistance are marked by single circle. Double circle numbers mean that those specimens have corrosion resistance next to that of single circle ones.
It is clearly seen that 2 S aluminium containing iron four times or so as much as silicon has better corrosion resistance in high temperature distilled water. Cold-rolled sheet has slightly better resistance to corrosion than annealed one and grain size seems to play a role. 52 S aluminium alloy, contrary to the conclusions in foreign literatures, is found to be fairly corrosion resistant in high temperature water.