【摘要】 本文对以往有关 Al 的孕育机理假设进行了考察,实验结果表明 Al 的孕育作用不是按 Swinden提出的复合铝硅酸盐假设机理产生的,并在实验的基础上,就 Al 的孕育机理提出了 Al 的氮化物(AlN)促进石墨形核的新看法更多还原

【Abstract】 Aluminium is known as an effective inoculant for iron foundry, but the inoculation mechanism of Al is not very clear so far. In this paper, a series of experiments have been performed in order to explain further the inoculation mechanism of Al in liquid iron and to compare the results with the previous works[1-4] in discussion. All the experimental results are shown in photos 1 to 12 and tables 1 to 5.In conclusion,1. Differing from B. Lus’s work[1], this paper gives experimental verification to show that his assumption, that A14C3 plays the role of germ nucleus in the inoculating effect of Al, is not true.2. Differing from J.F. Wallace’s workC2:? this paper points out that A12S3 also can’t play the role of germ nucleus,because its melting temperature is 1100 ℃[4]. With such a melting temperature, it is impossible for the solid phase to be stably formed in the range of the eutectic temperature of austenite/graphite.3. The argument by D. J. Swinden[3] is also untenable. He has supposed that aluminosilicate plays the role of germ nucleus in the inoculating effect of Al. Experiments show (see photo 11 and 12) that the weakened Al inoculation can not be restored effectively with the increase of oxygen content even if Al is added once again, but can be restored with the increase of nitrogen content (by adding Na4[Fe(CN)6]) in the same way. This means that the nitrogen in liquid iron significantly affects the inoculating effect of Al and the existence of a kind of compound of Al and N in graphite (AlN). The AlN, we believe, is probably the germ nucleus under the nucleation of graphite. This hypothesis is also verified by electron microprobe analysis.更多还原