Yield stress values of silicon nitride suspensions were measured via a novel slotted plater device and a constant stress rheometer and the results were compared. Test platform velocity, associated with thee slotted plate method, was found to have substantial effect on dynamic yield stress but not on static yield stress. The effects of suspension concentration and temperature on yield stress values were investigated. Yield stress measurements on mixtures of silicon nitride and alumina particles, as well as creep tests were performed.