J. Phys. IV France
Volume 125, June 2005
Page(s) 217 - 219

J. Phys. IV France 125 (2005) 217-219

DOI: 10.1051/jp4:2005125051

H2SO4 corrosion of API5L-X52 pipeline steel: Thermal diffusivity and microstructure

G. Peña-Rodríguez1, 2, C. Angeles-Chávez3, O. Flores-Macías3, E. Marín4, R.A. Muñoz Hernández1 and A. Calderón1

1  CICATA-IPN, Legaria 694 Colonia Irrigación, 11500 Mexico, DF, Mexico
2  Depto. de Física, U. Francisco de Paula Santander. A.A. 1055, Cúcuta, Colombia
3  Instituto Mexicano del Petróleo, Eje central L.Cardenas 152, 07730 Mexico, DF, Mexico
4  F. de Física, U. de la Habana, San Lazaro y L. Vedado 10400, La Habana, Cuba

The effect of corrosion by H2SO4 on the values of room temperature thermal diffusivity ($\alpha$) and the microstructure of API5L-X52 pipeline steel are studied. The samples were exposed for 3, 6, 9, 12 and 15 days in a corrosive solution in an atmosphere with relative humidity of 57.16% in average and at temperature of 23.6 °C. The $\alpha$ values were measured by the photoacoustic technique in a heat transmission configuration. Our results show a $\alpha$ decrease with the corrosion time (t), with a behavior described by an exponentially decreasing curve. Microestructural study on the samples revealed the appearance of irregular surfaces with corroded grain frontiers, porosity and fractures of micrometer size as a consequence of corrosion, as well as a presence of phases mainly composed by tetra hydrated iron and manganese sulphates. The decreasing evolution of $\alpha$ vs t show the activity-passivity behavior in the corrosion process.

© EDP Sciences 2005