Evaluación de la performance del recubrimiento de zinc en atmósfera marina en dependencia del espesor y tiempo de exposición
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Date
2024
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Publisher
Universidad Nacional de Trujillo
Abstract
En este trabajo se evaluó la performance del recubrimiento de zinc en la atmósfera marina
de Buenos Aires, Trujillo - Perú, en dependencia de su espesor y tiempo de exposición.
Durante un periodo de tres, seis, nueve y doce meses se expuso muestras de acero SAE 1020
de dimensiones 150x100x1.3mm con recubrimientos de zinc entre 8μm - 400μm. En base a
la norma ASTMB-119 a un grupo de estas se les practicó dos incisiones por muestra sobre
el recubrimiento de 60 mm de longitud, variando su ancho entre 1 y 5 mm paralelas a los
bordes, El proceso corrosivo de las muestras fue evaluado mediante observación visual
según norma ASTM D-610, también con microscopía electrónica de barrido (SEM) y
Espectroscopia de Rayos X por Dispersión de Energía (EDS) respecto a la distribución de
los productos de corrosión y contenido de elementos químicos tanto en la superficie del
recubrimiento como sobre las incisiones. Se estimó la pérdida de espesor en función del
tiempo, previamente eliminando los productos de corrosión formados de acuerdo a la norma
ASTM G1. El espesor mínimo de protección anticorrosiva de las muestras de acero para un
año de exposición fué del orden de 20μm. De cero a seis meses de exposición la pérdida de
espesor del recubrimiento electrolítico de zinc es aproximadamente constante. De seis a doce
meses de exposición la pérdida de espesor del recubrimiento electrolítico aumentó en
dependencia del espesor inicial del recubrimiento. Se identificaron los elementos de los
productos de corrosión a dos meses de exposición, encontrando sobre el recubrimiento Zn,
O, Na, C, Cl y menores porcentajes de S, Si y Al ; sobre las incisiones, en zona oscura: Fe,
O, C, Na y en menor proporción Cl , y en la zona blanca : Zn, O, C, Ca, Na, Mg, Fe con
menores porcentajes de K, Al, Si, S y Cl. Dentro de las incisiones, se van llenando los
productos de corrosión compuesto por zinc y otros elementos presentes en el medio, hasta
cubrirla según el espesor que este tenga.
In this work, the performance of the zinc coating in the marine atmosphere of Buenos Aires, Trujillo-Perú, was evaluated, depending on its thickness and exposure time. During a period of three, six, nine and twelve months, SAE 1020 steel samples of dimensions 150x100x1.3mm with zinc coatings between 8-400 μm were exposed. Base don the ASTMB-119 standard, a group of these underwent two insitions per sample on the 60mm long coating, varying their width betwee 1 and 5 mm parallel to the edges. The corrosive process of the plates was evaluated by visual observation according to ASTM D-610 standard, also with scanning electron microscopy (SEM) and Energy Dispersion X-Ray Spectroscopy (EDS) regarding the distribution of corrosion products and content of chemical elements both on the surface of the coating as over the incisions. The los of thickness was estimated as a function of time, previously eliminating the corrosion products formed according to the ASTM G1 standard. The minimum thickness of anticorrosive protection of the steel samples for one year of exposure was of the order of 20 μm. From zero to six months of exposure the loss of thickness of the zinc electrolytic coating is approximately constant. From six to twelve months of exposure, the loss of thickness of the electrolytic coating increased depending on the initial thickness of the coating. The elements of the corrosion products were identified after two months of exposure, finding Zn, O, Na, C, Cl on the coating, and lower percentages of S, Si and Al; over incisions, in dark zone: Fe, O, C, Na and in a lesser proportion Cl, and in the white zone: Zn, O, C, Ca, Na, Mg, Fe with lower percentages of K, Al, Si, S and Cl. Inside of the incisions, the corrosion products composed of zinc and other elements present in the médium are filled, until it is covered according to its thickness.
In this work, the performance of the zinc coating in the marine atmosphere of Buenos Aires, Trujillo-Perú, was evaluated, depending on its thickness and exposure time. During a period of three, six, nine and twelve months, SAE 1020 steel samples of dimensions 150x100x1.3mm with zinc coatings between 8-400 μm were exposed. Base don the ASTMB-119 standard, a group of these underwent two insitions per sample on the 60mm long coating, varying their width betwee 1 and 5 mm parallel to the edges. The corrosive process of the plates was evaluated by visual observation according to ASTM D-610 standard, also with scanning electron microscopy (SEM) and Energy Dispersion X-Ray Spectroscopy (EDS) regarding the distribution of corrosion products and content of chemical elements both on the surface of the coating as over the incisions. The los of thickness was estimated as a function of time, previously eliminating the corrosion products formed according to the ASTM G1 standard. The minimum thickness of anticorrosive protection of the steel samples for one year of exposure was of the order of 20 μm. From zero to six months of exposure the loss of thickness of the zinc electrolytic coating is approximately constant. From six to twelve months of exposure, the loss of thickness of the electrolytic coating increased depending on the initial thickness of the coating. The elements of the corrosion products were identified after two months of exposure, finding Zn, O, Na, C, Cl on the coating, and lower percentages of S, Si and Al; over incisions, in dark zone: Fe, O, C, Na and in a lesser proportion Cl, and in the white zone: Zn, O, C, Ca, Na, Mg, Fe with lower percentages of K, Al, Si, S and Cl. Inside of the incisions, the corrosion products composed of zinc and other elements present in the médium are filled, until it is covered according to its thickness.
Description
Keywords
Corrosión atmosférica marina, Recubrimiento de zinc, Productos de corrosión del zinc, Productos de corrosión del hierro