Decomposition products of superconducting (Bi,Pb)2Sr2Ca2Cu3O10+dgr;

摘要

High‐temperatureinsitux‐ray studies of Pb‐doped Bi2Sr2Ca2Cu3O10+dgr;have been carried out in a variety of different environments in order to determine the range of stability and the decomposition products that appear as this material transforms into other phases. In air at 840 °C, a combination of Bi2Sr2Ca0Cu1O6+dgr;, Ca2PbO4, (Sr,Ca)2Cu1O3, and some liquid phase coexists with Bi2Sr2Ca2Cu3O10+dgr;as it gradually decomposes. When the Bi2Sr2Ca2Cu3O10+dgr;is completely gone, the Bi2Sr2Ca0Cu1O6+dgr;, Ca2PbO4, and (Sr,Ca)2Cu1O3transform to a liquid with CaO and other phases floating on the liquid. If Ag is micromilled with the Bi2Sr2Ca2Cu3O10+dgr;, the decomposition process is similar, but all of the temperatures are lowered substantially. If the partial pressure of O2is reduced to 10 kPa over the Bi2Sr2Ca2Cu3O10+dgr;/Ag sample, the decomposition temperatures and products are similar to the 20 kPa case.