Quantitative Analysis of Gamma Prime Phase in Nickel Base Superalloys

Abstract

A rapid and precise method for quantitative analysis of γ' phase in nickel base superalloys has been developed by improving of extraction method of the precipitates.
The results obtained are summarized as follows:
(1)The precipitates including γ' phase are quantitatively and precisely extracted by potentiostatic electrolysis in 1% ammonium sulfate-1% tartaric acid-water or 1% ammonium sulfate-1% citric acid-water electrolyte.
(2)Only the γ' phase adhered to the sample surface after potentiostatic electrolysis can be dissolved by dipping samples into (1+4)HCl solution at 60°C for 10 minutes.
(3)The amount and chemical composition of γ' phase and other precipitates can be determined respectively by analyzing solution and residues obtained from the above mentioned (2).
(4)The rapidity and precision of this method is excellent compared with the conventional methods which use filtration or centrifugation for collection of residues.
(5)This method gave instructive informations about precipitation behavior of γ' phase.