Analysis and Modelling of Oxygen Diffusion in under Non-isothermal Conditions

摘要

Thermogravimetric analysis (TGA) has been used to measure oxygen diffusion in YBa_2Cu_3O_(7-δ)(YBCO) powder and single crystals in a pure oxygen atmosphere. Measurements were made up to 700 °C and the experiments were carried out at constant heating rate. A computational model that reproduces the weight change of an YBCO sample under non-isothermal conditions has been developed. Constant ramp rate experiments avoid the problem of initial transients encountered in isothermal experiments and can be analysed quantitatively for the diffusion constant and activation energy.