Fabrication and characterization of mini alumina ceramic turbine rotor using a tailored gelcasting process

A mini alumina ceramic turbine rotor has been successfully fabricated using a tailored colloidal process based on gelcasting technology. A specialized forming, drying and sintering approach was developed for the complex-shaped component with both large volume (90 mm in diameter and 20 mm in height) and submillimeter geometry (0.42 mm at the blade tip with curvature), to assure a highly dense product without warpage and cracks. The effects of solid content and temperature on the rheological behaviors of the prepared slurry were investigated to identify the best pourability. A novel approach using radius of curvature and overlapped area was adopted to compare the blade contour similarity under different sintering strategies and solid contents. In addition, the different physical and mechanical properties between main body and blade regions were discussed and their microstructures were analyzed. The preparation route for highly dense alumina rotor with minimum contour distortion was finally summarized.