The presence of non-resistance elements to corrosion such as Mg, Si and Cu, as well as microstructural malfunctions, including pores in aluminum alloys have caused the alloys to have relatively low corrosion resistance and mechanical properties.
According to Iran Nanotechnology Initiative Council (INIC), Iranian researchers from Tarbiat Modares University carried out a study to increase the resistance of alloys, and they succeeded in the production of laboratorial nanocoatings with desirable properties such as high corrosion and abrasion resistance.
A nanocoating was produced in this research to protect alloys. To this end, surface nanocrystalline pre-process has been used through plasma electrolyte oxidation (PEO) or microsparkle oxidation method.
Microsparkle oxidation is a surface process that has been widely used in recent years. Taking into consideration the fact that microsparkle oxidation process highly depends on the microstructure of the substrate, it seems that the nano-crystallization of aluminum alloy surface significantly affects the properties of the produced coating. This fact has been studied in the present research.
Results showed that the samples coated in silicate-based electrolyte have firmer structure than the samples coated in phosphate-based electrolyte. This fact results in more pores and it reduces resistance to corrosion. In addition, the average of pore area percentage on the surface of samples coated in silicate-based electrolyte is higher than that of samples coated in phosphate-based electrolyte. In other words, corrosion resistance is higher in coatings produced in phosphate-based electrolyte.
Results of the research have been published in Bulletin of Materials Science, vol. 38, issue 4, 2015, pp. 935-943.
MS/PR
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