Development of coated ceramic components for the aluminum industry

In general, due to ceramic's high hardness, which makes machining operations extremely difficult and very expensive, ceramic components are formed in shapes very close to the final ones. Considering this, a manufacturing process, based on a sol-gel reaction that allows rapid production of ceramic components in the final shape with a low level of shrinkage was developed. Although the ceramics obtained presented good behavior in short-term contact with molten aluminum alloys, there was no guarantee that the components produced would have adequate continuous resistance to chemical and erosive wear by liquid metals. To enhance their resistance, the ceramic parts were coated by flame spray. Different powders and conditions were used to determine the degree of coating adhesion to the substrate. The coated specimens were then submerged in a molten aluminum bath, at different temperatures and time settings, to evaluate the interaction between the ceramic components and the molten aluminum alloys.