THE INFLUENCE OF Bi2O3 ADDITIONS ON THE SINTERING AND THE MAGNETIC PROPERTIES OF STRONTIUM FERRITE

摘要

Bismuth oxide is very beneficial in raising the coercivity of strontium ferrite magnets. The addition of SiO3 influences die temperature at which the sintering starts and the temperature at which the maximum density may be obtained, probably due to the formation of liquid phase during the sintering. Microprobe analysis showed presence of Si203—rich grain boundary phase with the composition 30-32 % Bi203, 18-20 % SrO and 49- 50 % Bi203'. Grain growth is primarly control¬led by the residual porosity and is not particularly sensitive to the 3i203 additions.