Influence of modern aluminium alloys on the reaction behavior of refractory linings

Abstract

For modern aluminum alloy production, constituents of silicon, zinc, and magnesium contribute mainly to the degradation of refractory furnace linings. The alloy constituents increasingly penetrate the material via the vapor phase. This study intends to enhance understanding, describe and characterize the interactions between refractories used in holding and melting furnaces of the aluminum industry. The damage mechanisms occurring due to corrosion are verified and determined by applying various test methods and atmospheres. The present study focuses on the impact of zinc (Zn) and magnesium (Mg) as a gaseous component on refractory linings. The examined materials of this study are bauxite-based bricks with phosphate bonding and bricks with either CA 6 or sol-gel bonding, both based on high alumina. The experimental setup of the corrosion tube furnace consists of a crucible filled with solid metal and two identical bars of the refractory sample. Metallic zinc, magnesium, and the Al alloy EN-AW7075 are within this study's scope. Further conditions are a testing temperature of 1050 • C and increasing test duration of 2, 8, 24, and 36 h. The experiments have shown that zinc and magnesium both have an extreme influence, especially on the microstructure, which is accompanied by both positive and negative property changes. These are dependent on both the bonding type and the ambient atmosphere.