Experimental Study on Purification of C54-TiSi2 from Alloy Through Alkaline-Leaching Desilication

C54-TiSi2 is a promising semiconductor material for integrated circuits due to its excellent electrical properties. However, during the preparation of C54-TiSi2 through electromagnetic directional solidification, the presence of silicon (Si) inclusions can increase resistivity and adversely affect performance. This study investigated the use of sodium hydroxide (NaOH) as a leaching agent to remove Si inclusions from C54-TiSi2 crystals. Thermodynamic analysis and alkali-leaching experiments were conducted, which focused on the morphological characteristics and distribution patterns of Si within C54-TiSi2. The results indicated that the Si impurity content increased with increasing ingot thickness, and the morphology of Si was determined by the pores formed between C54-TiSi2 crystals. Furthermore, NaOH alkaline leaching effectively desilicated the Si without compromising the lattice structure of C54-TiSi2 crystals. Subsequently, with optimal leaching parameters of 15 pct NaOH concentration, a temperature of 70 degrees C, a leaching time of 20 minutes, and a liquid-to-solid ratio (L/S) of 4:1, the purity of C54-TiSi2 crystals exceeded 99.5 pct, thereby achieving a Si removal rate of 99 pct. After the alkali-leaching and purification process, the resistivity of C54-TiSi2 decreased from 8.35 x 10-5 to 4.75 x 10-5 Omega cm, which was significantly lower compared with the resistivity of commercially available C54-TiSi2, thereby enhancing its electrical properties. This study offered theoretical insight and data support for the purification and performance assessment of C54-TiSi2 crystals.