It is reported that the Bi metal/ceramics composites can show PTCR properties at the melting point of Bi metal of about 270 °C. This materials have a few advantages such as low resistivity and high FFCR properties, but there is the problem that the resistivity doesn't coincide with the original value after the cycle measurement. This will be originated from Bi metal rearrangement during melting. Further densifications of ceramic matrix phase will overcome this problem. The purpose of the present study is to prepare high-density sample by hot-pressing, and to clarify the relationship between resistivity-temperature characteristics and microstructures in obtaining the optimum conditions of hot-pressing. The relative density of hot-pressed 0.55Bi-0.45SrBi4(Ti0.95Nb0.05)4O15 with using fine Bi metal reached more than 99% and its resistivity of nearly 10-1Ωm at room temperature remains unchanged after cycle measurement. In addition, the magnitudes of PTCR effect reaches 7 order of magnitude, and resistivity-temperature curve also remains unchanged even after 3rd measurements.
|Number of pages
|Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
|Published - 1999 Jul