Production and characterization of a Fe-Ni alloy by aqueous coloidal processing and solid state reaction

Colloidal processing is a widely used technique to produce ceramic components. Several papers have been published in the last decade presenting the possibility to obtain aqueous concentrate stable suspension of metallic particles from their pH control and using dispersants. This paper aims to study the production of a steel with austenitic microstructure using elemental iron (Fe) and nickel (Ni) powders via colloidal route. For this, Zeta potential measurements were performed between pH 2 and 12 to Fe30Ni wt% composition. Aqueous suspensions reached solids concentrations of up to 45% v/v and processed by slip casting. The compacts were characterized by density (Archimedes), differential thermal analysis (DTA) and dilatometry. After sintering at 900°C to 1100°C/1h, the sintered bodies presented a microstructure with of annealing twins, porosity less than 10 %v/v approximate Vickers microhardness of 160 HV. (author)