关键词: 溶胶凝胶法, 柠檬酸, YBa2Cu3O7-δ, 自燃, 粉末粒度

Abstract: Homogeneous YBa2Cu3O7-δ powder was prepared through sol-gel process. The citric acid was used as complexing agent to form macromolecule compound with Y³⁺, Ba²⁺ and Cu²⁺ ions. After dehydration the compound grew into small particle clusters which bonded together to form continuous three-dimension net. The pH value of citrate solution should be controlled in a range from 6.4 to 6.7 to prevent from forming Ba(NO3)2 sediment and ensure the quality of gel. It' s preferable to control the evaporating temperature at 300°C so as to form gel in shortened time continuously along with its spontaneous combustion process at the same temperature. Thus the process is simplified. The temperature required for synthesizing YBa2Cu3O7-δ powder is about 880°C, at which the particle size is about 0.2-1 μm.