Phase stability and enhanced mechanical properties of ferro-titanium slag to aluminum titanate ceramics

Abstract

• The addition of ferro-titanium slag improves the strength of the material. • Impurities in ferrotitanium slag form solid solution with aluminum titanate. • The formation of solid solution inhibits the decomposition of aluminum titanate. • Recycling and harmless utilization of metallurgical waste slag. Ferro-titanium slag is a waste slag from ferro-titanium alloy smelting. It has high strength and has been observed to act as a reinforcing phase in multiphase materials, of which ferro-titanium slag powders were chosen to inhibit the thermal decomposition of AT ceramic in 800–1300 °C temperature range and improve its mechanical strength. It was shown that Si 4 + , Fe 3 + and Ti 4 + ions in ferro-titanium slag can partially replace Al 3 + ion in AT to form an ATFS (the AT ceramic doped with SiO 2 and Fe 2 O 3 ) solid solution, which inhibited the decomposition of AT. In addition, the formation of CA 6 phase contained from phase reconstruction of ferro-titanium slag further reinforced the mechanical properties of the AT ceramic. When 50 wt% ferro-titanium slag was added, the CA 6 enhanced AT multiphase ceramic improved phase stability and reaches mechanical properties (≈14 MPa).