Aqueous slurry erosion in some cobalt base superalloys

An orifice erosion test was used to study the influence of metallurgical variables in a series of cobalt base superalloys on their resistance to erosion by aqueous slurries of SiO₂. A slurry of 30 pct solids by weight of 4.5 μm silica was used to erode a variety of microstructures obtained by compositional and processing control. The time de-pendence of the pressure drop across an orifice (P) was found to follow the relationP = Kt^-@#@ n wheret is time (min), andK andn are constants. The erosion exponent,n, varied from 0.052 to 0.148 and was found to be dependent upon carbon content and processing variables.