METHOD FOR DETERMINING DIFFUSION CONSTANTS IN POLYCRYSTALLINE MATERIALS Russian patent published in 2006 - IPC G01N13/00 

FIELD: controlling and measuring equipment, possible use for determining oxygen diffusion parameters in solid polycrystalline bodies in science of materials or solid body physics.

SUBSTANCE: in accordance to method for determining diffusion constants in polycrystalline materials, sample is heated up in vacuum, exposed in heated state and cooled down to room temperature, after that sample is moved to open air, heated up, exposed in heated state, cooled down, diffusion coefficients are determined, and given order of actions is repeated for various sample heating temperatures, graph of temperature dependence of diffusion coefficients is built, diffusion constants are determined on basis of results of approximation of given relation using Arrenius rule. For given temperature of sample heating at open air, series of actions concerning heating up sample, exposing it in heated state and cooling down is repeated multiple times, while heated state sample exposure time is set equal to 10-15 minutes, and after each such cooling, value of energy of activation of electric conductivity in surface-adjacent layer of sample is measured, and if value of electric conductivity activation value coincides with value received in previous measurement, actions at open air concerning heating up sample, exposure thereof in heated state and cooling down are stopped, then curved graph is built indicating dependence of value of electric conductivity activation energy on total time of exposure of sample in heated state, and diffusion coefficients for given sample heating temperature are determined from results of curve approximation using expression, connecting value of electric conductivity activation energy in surface-adjacent layer of sample after next delay of sample in heated state with concentration of ions diffused therein up to current moment in its turn given in form of solution for Fick expression with appropriate boundary conditions.

EFFECT: increased precision and creation of method for determining diffusion constants not destroying the sample.

3 dwg, 1 tbl