PRESSURELESS SINTERING OF TIB2–BASED COMPOSITES USING TI AND FE ADDITIVES FOR DEVELOPMENT OF WETTABLE CATHODES

摘要

Titanium diboride is the most promising candidate material fordevelopment of wettable cathodes for aluminum smelting. It isconsidered as an alternative for carbon cathodes in order to reducethe anode cathode distance resulting in higher energy efficiency inelectrolysis cells. In this work, TiB_2-based ceramic specimenswere consolidated using metallic additives followed bypressureless sintering. Different proportions of iron and titanium(≤ 10 wt%) were used as low melting point sintering additives.Sintering was conducted at 1400–1650°C under controlledatmosphere. The effects of composition, sintering temperature,milling time and pre-alloying of the additives on densification,microstructure, and mechanical properties were investigated. Itwas found that pre-alloying and milling time have significantinfluence on densification, microstructure uniformity and bendingstrength. Uniform crack-free microstructure with even distributionof pores as well as maximum relative density of 91% and bendingstrength of 300 MPa were obtained using pre-alloyed additives,milling time of 30 min and sintering for 1 h at 1650°C.