鉄材とアルミニウム溶湯との反応におよぼすけい素の影響

鉄材と溶融アルミニウムとの反応 (第2報)

抄録

In order to study the effects of silicon on the reaction of solid iron with liquid aluminum, iron specimens having various carbon and silicon contents were immersed in pure liquid aluminum or liquid Al-Si alloys at 700-770°C for a considerably long time.
The degree of corrosion of iron attacked by liquid aluminum was determined by the weight loss during reaction, and the properties of Fe-Al reaction zone were investigated by means of microhardness tester, X-ray diffractometer, and electron-probe microanalyzer.
When some kinds of iron were immersed in liquid Al-Si alloys, or some Fe-Si alloys were immersed in pure liquid aluminum at the temperature of 110°C above liquidus, silicon (either in iron or aluminum) had no effects on weight difference of iron specimens, but the thickness of reaction zone decreased with the increase of silicon content. Silicon in liquid aluminum did not inhibit the growth of reaction zone, but accelerated its dissolution into liquid aluminum.
When silicon was added into iron or liquid aluminum, two layers were always present in the reaction zone; i.e., one of which close to the iron matrix was composed of Fe₂Al₅ and the other close to aluminum was composed of the mixture of FeAl₃ and aluminum. High silicon layer was formed when silicon content in Fe-Si alloys was higher than a certain limit (about 3% of Si). The solubility limit of silicon in columnar layer was determined to be 2-3% by electron-probe analysis. The hardness of reaction zone was not affected by silicon content in iron.