Aluminium composite casting carried by stir casting process. The stirrer rod used is made up of stainless steel 310, to avoid the surface reaction on the blade and rod they go for a zirconium coating. I would like to know what are the alternate surface coatings.
I used the "Dycote 39" for coating of my stirrer in Aluminum semi-solid casting.
The main material in Dycote is TiO2.
@ Milad Baygan
Thanks... I would like to know more about this Dycote 39 coating such as working temperature and the life of the coating and the reactions takes place on the surface of the coatings.
Stir casting is not my background but a quick search shows that some stirrer blades are coated with zirconia or zirconium oxide to avoid reaction with the Al. In this case, a conventional thermal sprayed partially-stabilized zirconia can be an alternative. If this is what you are trying to replace, a nanostructured form may be an option. Nanostructured oxide coatings have been very successfully applied for severe-service stir blades in pressure acid leach and pressure oxidation environments. We have developed a nanostructured zirconia-base coating.
Chromium electroplating can be used to protect grade 310 stainless steel from molten Al. Another alternative protective technique might involve coating with Al by hot dipping, followed by oxidation to form a surface layer of Al2O3 which should protect from corrosion by the Al melt (*).
(*) Cf: W. Deqing, S. Ziyuan, Z. Longjiang, "A liquid aluminum corrosion resistance surface on steel substrate", Applied Surface Science, 214(1-4), 2003, 304-311.