-

The formation of columnar structure in Alnico alloys enhances markedly its magnetic properties. The addition of Ti to these alloys also improves the magnetic properties but restrains formation of columnar structure. By addition of some elements such as C, S, Se, Te or P the columnar structure could be obtained again.
In this work, the effects of C and S on the formation of columnar structure have been studied. Experimental results and thermo dynamical analysis show that carbon prevents formation of titanium oxide inclusions by deoxidation of the melt, in the meantime, sulfur precipitates as titanium suiphide on the surface of titanium nitride inclusions. Hence nucleation effects of titanium inclusions which makes the structure non-columnar is controlled.