| 摘要 |
PURPOSE:To estimate the degree of deterioration of creep ductility by making constant potential polarization measurement with a metallic material to be measured as an anode and measuring the anode current density in an anode current stagnating region. CONSTITUTION:An electrolytic cell 2 is mounted to the measuring point of the metallic material 1 to be measured in a manner that an electrolyte 3 contacts directly with the material 1. The cell is sealed 4 by rubber or clay to prevent the leakage of the electrolyte 3. The polarization measurement is carried out after connecting the material 1 as the anode to the positive voltage side of a potentiometer 6 and connecting an inert electrode inserted into the electrolyte 3, for example, a platinum electrode 5 as a cathode to the negative voltage side of the potentiometer 6. The measurement is executed by measuring the anode current at a specified potential sweep speed after the cathode reduction at the natural electrode potential or below. The stagnating region of the anode current density appears near the critical potential for passivation on the anode polarization curve on gradual deteriorating of the material. The stagnating region has a close relation with the creep rupture ductility of the material. The degree of deterioration of the material is known by comparing and evaluating such stagnating region value, by which the prediction of the remaining life is made possible. |
