PURPOSE: To achieve a shorter measuring time and a higher accuracy of the sensitivity, by measuring the polarization characteristic only in the passivity area without passage through an active area.
CONSTITUTION: A heat-resisting steel as sample to be tested is arranged as anode 2 facing a cathode 3 in an electrolytic liquid 1 containing organic acid and alkyl benzene sulfonate or a salt thereof and an external power source 4 is connected to both the electrodes to provide a potential so that the current flowing through a circuit is measured with an ammeter 5 or the potential of the sample is measured with a potentiometer 7 based on a collation electrode 6. A fixed voltage E1 is applied to a heat resisting steel 2 connected to the polarization curve measuring device thus obtained and then, lowered at a fixed rate after held up to a fixed time t0. The very small current density changes as shown by (d) and (f) depending on the presence of annealing brittleness. Thus, possible embrittlement can be evaluated qualitatively by detecting the difference in the very small current density.
HIRATA HIDEYUKI
KIMURA KAZUNARI
Next Patent: MANUFACTURE OF SAMPLE FOR ULTRASONIC FLAW DETECTION