THE ROLE OF ALUMINA IN THE GROWTH-MECHANISM OF BI(PB)-SR-CA-CU-O WHISKERS

We studied the growth mechanism of whiskers from alumina-containing Bi(Pb)SrCaCuO glass plates by using thermal, in-situ high-temperature X-ray diffraction, microstructural and compositional analyses. The Al3+ in the glass helps to form the complex oxide particles such as BiSrCaAlO in the sample. These particles block the liquid phase inside the sample and prevent the leakage. The whisker grows because Bi2Sr2Ca1Cu2Ox (Bi-2212) continuously precipitates from this liquid at the bottom part of the whiskers. The capillary force between the BiSrCaAlO particles leads the liquid to the bottom part of the whiskers. Due to this force it is possible to supply the ingredient to the whisker continuously. On the basis of the above analysis, the role of alumina was studied in detail.