On the development of gelcasting process for tungsten and its alloys

Abstract

Gelcasting technique has been successfully used for the preparation of porous tungsten. Gel forming monomer (methacrylamide (MAM)) and Cross-linker (NN’-Methylenebisacrylamide (MBAM)) dissolved in water were used for gelcasting of green compacts of tungsten with 39% solid loading. Appropriate quantity of dispersant, initiator, and catalyst were used in order to obtain a uniform dispersion of tungsten particles and also control the polymerization process. Several issues related to dispersant selection, de-airing, de-bindering, sintering, and selection of mold material have been addressed in order to obtain a defect-free product. Theoretical density of the porous sintered tungsten pellets produced by gelcasting process is ∼85%. The average pore diameter and mean pore area are 3 µm and 16 µm2, respectively, which are specifically required for the cathode application. Complex shape components of pure tungsten have been successfully made using gelcasting technique for the first time.