Potentiodynamic study of lead babbit BLa (PbSb15Sn10), with lanthanum, in the electrolyte environment NaCl

Abstract

The results of a corrosion-electrochemical study of the effect of lanthanum additives as an alloying component on the anodic behavior of lead babbit of the BLa brand (PbSb15Sn10), in a NaCl electrolyte medium with a concentration of 0.03; 0.3 and 3.0 % (by weight) are presented. The anodic behavior of babbits was investigated by the potentiostatic method at a potential sweep rate of 2 mV/s. The lanthanum content in lead babbit BLa (PbSb15Sn10) was 0.01, 0.1, 0.50 and 1.0 % (by weight). It was found that with an increase in the concentration of chloride ion in the NaCl electrolyte, there is a shift in the negative region of the values of the potentials of corrosion, pitting formation and repassivation of babbits. The free corrosion potential of lead babbit shifts from time to time to the positive region. Regardless of the composition of babbits, an increase in the rate of their corrosion was established with an increase in the concentration of NaCl in the electrolyte. The addition of lanthanum to lead babbit increases its corrosion resistance. It is shown that lead babbit corrodes by the pitting mechanism and lanthanum as an alloying component of lead babbit BLa (PbSb15Sn10) contributes to the shift of the potentials of pitting formation and repassivation to the region of positive values. This leads to an increase in the resistance of lead babbit to pitting corrosion, and also contributes to the healing of incipient pitting foci.