ABATIMIENTO DEL POTENCIAL ELECTROQUÍMICO DE CORROSIÓN DE ACERO INOXIDABLE AUSTENÍTICO BAJO CONDICIONES DE REACTOR BWR APLICANDO DEPÓSITOS DE ZRO2 Y DE NANOPARTÍCULAS DE PLATA

Abstract

ECPSHE has been abated for 304SS specimens processed under two different treatments: 1) oxidation of 304SS specimen surface followed by Ag NP’s deposit, 2) oxidation of 304SS specimen surface followed by a ZrO2 NP’s coating, as a reference specimen the 304SS specimen only oxidized was used. The experiments were accomplished under environment similar to those of a BWR in operation: 288 °C, 8.3 MPa, in water of high purity, and injecting H2 gas. In each one of the experiments, the ECPSHE obtained for 304SS specimens with silver nanoparticles deposit or with zirconium oxide coating always were more negative than the obtained for the reference specimen. It is proposed that with a deposit of silver nanoparticles of mean particle size of 2.72 nm over 304SS, the ECPSHE abatement is attained by the catalytic reduction reaction of O2 with H2 to obtain water. On the other hand, coating of the 304SS surface with zirconium oxide nanoparticles of 3.72 nm mean size, allowed to form a physical barrier that avoided oxidant species in water to reach the 304SS surface. At a 1.86 mM ZrO2 concentration, an ECPSHE of -350 mV was registered, with the larger time remaining the protective effect. The 304SS specimens with the three types of treatment were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectroscopy. The ECPSHE of the 304SS specimen treated with a AgNP’s deposit and those treated with zirconium oxide NP’s allowed the abatement of the ECPSHE lower than the critic value of -230 mV. Based on the obtained results, we can suggest the application.