Formation of Corundum, Magnesium Titanate, and Titanium(III) Oxide at the Interface between Rutile and Molten Al or AlSi7Mg0.6 Alloy

Abstract

For the filtration of oxide inclusions in aluminum melts, active materials covering the surface of ceramic filters are developed permanently. In this study, corundum (a-Al 2 O 3 ) filters coated with rutile (TiO 2 ) coatings are exposed to molten aluminum and to aluminum alloy AlSi7Mg0.6, respectively. For pure aluminum, the chemical reactions occurring at the interface between the metal melt and the filter surface are found to lead primarily to the formation of Al 2 O 3 at the surface of the functionalized filter. Al 3 Ti and Ti 2 O 3 are found as minor phases for long operation times. In the case of aluminum alloy AlSi7Mg0.6, the surface of the TiO 2 coatings is covered by MgTiO 3 . Additional phases are Al 2 O 3 and Al 3 Ti. One part of the interface reaction experiments is performed on powder mixtures to identify the reaction products, another one on functionalized filters to estimate the reaction kinetics. The experiments are performed in a Spark Plasma Sintering apparatus, which offers high heating rates that are comparable with those in standard cast processes, but impedes the macroscopic flow of the melt in case of the bulk samples. The equilibrium state is concluded from thermodynamic calculations using the CalPhaD method.

Liquid Immiscibility and Thermodynamic Assessment of the Al2O3–TiO2–SiO2 System

“…The reduction of TiO 2 can then lead to the formation of Al 3 Ti or (Al,Si) 3 Ti. [3] Therefore, to model Al melt filtration process, one should consider the Al-Mg-Ti-Si-O system. As a part of the mentioned complex system, the Al 2 O 3 -TiO 2 -SiO 2 sub-system was recently investigated experimentally.…”

Analysis of the Technological Position in Relation to Aluminium Casting Production

“…Thanks to the presence of such elements as silicon and magnesium, the alloy exhibits relatively good mechanical properties (Briol, 2010;Mueller et al 2016). The alloy has exceptional corrosion resistance and very good machining and welding properties (Julis et al, 2011;Pereira et al, 2020;Salomon et al, 2017). For this reason, the alloy is used in automotive, architectural, aerospace (Brungs, 1997;Cavaliera et al, 2004), food and chemical industries, mechanical engineering and in shipbuilding and moulds and models (Chokkalingam et al, 2017;Pysz et al, 2014).…”

The use of combined quality management instruments to analyze the causes of non-conformities in the castings of the cover of the rail vehicle bearing housing

“…(Briol, 2010). The distinguishing feature of the alloy is its exceptional corrosion resistance, good weldability, and very good machining properties (Julis et al, 2011;Salomon et al, 2017;Yang et al, 2019). For this reason, the alloy has been used in architecture, aviation, automotive (Brungs, 1997;Cavaliere et al, 2004;, food and chemical industry, mechanical engineering, shipbuilding, models, and forms (Hurtalová et al, 2011;Hurtalová et al, 2013;Poloczek and Kiełbus, 2016;Mueller et al, 2016).…”