Preparation and application of unfired Al2O3–Al–C slide plate materials in the presence of trace Zn

Abstract

The unfired Al2O3–Al–C slide plates were prepared using tabular alumina aggregates and fines, Al powder and graphite powder as starting materials, and phenol formaldehyde resin as binder. The effects of trace Zn on properties and microstructure of samples at elevated temperatures were investigated. Post mortem investigations on the newly developed Al2O3–Al–C slide plates with trace Zn were carried out. The results showed that the properties of the unfired slide plate materials at low temperature (500–700 °C) were remarkably enhanced in presence of trace Zn, and the high temperature properties above 1000 °C of the slide plates with Zn were also greatly improved in comparison to the conventional ones. After used in 90 t ladles for 2 consecutive heats, the bore enlargement of the newly developed slide plates was less than 2 mm/heat, and roughening on the sliding surface was slight, showing good high temperature service performance. The improved properties were attributed to the high reactive Zn reacting with O2 or CO to form ZnO ceramic phase and protected phenolic resin from oxidation at low temperature, and the vaporized Zn could promote non-oxide Al4C3 and AlN formation and growth at high temperature, creating strengthening and toughening effects.