Two metallographic etchants were employed to characterize the γ′ precipitates in a single crystal Nickel-base superalloy. One can corrode γ matrix and retain γ′ precipitates, while the other one can remove γ′ and obtain γ. Potentiodynamic polarization curves of γ′ precipitates and γ matrix in these two etchants were measured to examine the electrochemical process of metallographic etching. The results from the electrochemical tests showed that the corrosion potential (Ecorr) of each phase determined the metallographic etching morphol...
