Effect of Dispersant on Fiber-Reinforced Shell for Investment Casting

In this study, a novel preparation route of shells for investment casting was proposed. To this end, hydroxypropyl methylcellulose (HPMC) was used as fiber dispersant, and its influences on rheological behaviors of slurry and strength of shell were studied. The addition of carbon fibers with different lengths and concentrations was also explored. The results suggested that suspension and viscosity of the slurries with HPMC were higher than those prepared without HPMC due to dispersion and tackily effects of HPMC on fibers and slurries. The fibers were found uniformly dispersed in the slurry, and fracture shell was uniformly distributed in the shell thanks to the presence of the dispersant, leading to enhanced shell strength. In addition, higher firing temperatures led to denser shell and superior strength.