抄録
Mill carhurizatiui by such a sappressor as alumian or phosphatesystem was studied. It was found that the suppressor either Al2O3 or Ca3(PO4)2 reacted with the promoter BaCO3 or Na2CO3, forming aluminate (BaO•Al2O3) or phosphate [Ba3(PO1)2 or Na3PO4] at carburzing temperature. The intensity of the promotice power of BaCO3 for Na2CO3 was depressed when used together with a suppresser of alumina or phosphatesystem, because their reaction products had little effect on carburizing. Al or Fe-Al as the suppressor of alumina-system was oxidized in carburizing atmosphare forndng alumina, and then the alumina reactcl with the promoters as above. On the other hand, Al, diffusing into the surface of steel, suppressed carburizing. When bone-black was used in carburization, phosphate in it having been reduced the produced vapour of plusphor diffused into steel. But the phosphor scarcely effected carburizing. Finally, on the stand punt of rate process, mechanism of depression in promotive power of BaCO3, and Na2CO3 by the reacthvi with suppressors was considered.
