METHOD AND APPARATUS FOR MEASUREMENT OF HYDROGEN DIFFUSION COEFFICIENT OF STRESS-LOADED METAL MATERIAL

PURPOSE:To measure the hydrogen diffusion coefficient of a metal material in a stress-loaded state based on actuality by a method wherein a metal sample is exposed to a hydrogen-intruded atmosphere, the sample is loaded with a stress, hydrogen which has reached a space inside the sample is conveyed continuously or intermittently to a hydrogen detector and the concentration of the hydrogen is measured. CONSTITUTION:A sample 1 is immersed in an electrolyte 15, and the electrolyte is kept at a specific temperature by a temperature regulator 17. Then, a platinum anode 15 is set as an anode, the sample is set as a cathode, a constant-current electrolysis operation is performed, and hydrogen which is generated by the cathode is supplied continuously to the sample. The sample 1 is fixed by sample-fixing utensils 18, 19, and it is loaded with a tensile stress by a weight 20. A dehumidified or inert gas is sent continuously or intermittently to a gas supply connector 5 by a gas supply device 7. The hydrogen which has invaded into the sample 1 and reached a space 2 inside a pipe is conveyed to a hydrogen detection device 8 from a gas carrying-out connector 6, and the concentration of the hydrogen is measured. In addition, the concentration is compared with a theoretical curve on the basis of Fick's diffusion equation by a data processor 11, and a hydrogen diffusion coefficient under a stress-loaded state is computed.