Characterization of sol-gel coatings deposited on a mechanically treated stainless steel by using a simple non-destructive electrical method

Abstract

Coating solution of yttria-doped zirconia was prepared by using the sol-gel method and deposited on AISI 304 stainless steel substrates using dip-coating technique. The influence of the mechanical modification of stainless steel substrates and withdrawal rate on the coating quality has been studied. Herein, a novel method based on measuring the electrical capacitance of such coatings is developed in order to assess the coating quality. The method was performed on sanded and polished samples coated at various withdrawal rates, obtaining the greater thickness uniformity for the coatings deposited on polished specimens coated at a withdrawal rate of 25 mm-min-1. The results obtained by the proposed method are well in agreement with those found by both optical and electron microscopies. Therefore, such a method seems to be of great interest because of its simplicity and low cost as compared to other well-established techniques, and its results may be a great support for them.