Corrosion protection of metal substrate is researcher's concern for many years. Accordingly, different methods are used for better application of metal instruments. In this research, it has been focused on conversion coatings due to their uniform film formation on metal surface, better interlayer adhesion and easier application. Moreover, these coatings act as a barrier between the substrate and environment and protect the substrate from corrosion and also improve the adhesion of the organic coating to metal surface due to the increment of the surface energy.
In the recent years, many attempts are conducted to upgrade the conversion coating's properties. Consequently, the effect of adding rare earth elements to improve conversion coatings and their corrosion protection is studied. But the main issue of these coatings are producing small cracks in final coating. Therefore, in this paper, the approach is to eliminate the cracks are investigated.
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