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Method for Detecting Compositional Changes in Gray Cast Iron Pipes and Conductive Materials With Varying Properties

The UH method can sensitively and non-destructively detect and locate de-alloyed sites in gray cast iron and other alloys based on the distinct electrochemical difference between the base alloy and the dealloyed region. This method can detect and discriminate between the stages of de-alloying from early to late stage. This method uses a newly developed solid state electrochemical probe that provides very stable measurements and precludes problems of electrolyte leakage. This allows measurements on any surface finish in any orientation. This detector can detect de-alloying in other alloys that experience this form of corrosion including dezincification in CuZn alloys, denickelification in CuNi alloys, de-cobaltification in Co-based alloys, and de-carburizaton in carbon containing alloys. In particular, the present invention relates to a field deployable electrochemical non-destructive evaluation (NDE) sensor for the quantification of de-alloying in gray cast iron and other alloys.

Applications

  • Assess the severity of dealloying damage on alloys such as gray cast iron, Cu-Ni alloys and other alloys critical to infrastructure/li>
  • Uses a new solid state probe that eliminates electrolyte leakage and provides electrochemical stability
  • Can apply DC and AC electrochemical methods using 2 and 3 electrode configuration
  • Based on differences in electrochemical behavior of the alloyed vs. de-alloyed regions in gray cast iron, the UH detection system will provide very high contrast between alloyed and de-alloyed regions. It can also be configured to detect de-alloyed regions in the presence of biofilms and corrosion product layers

Problems Addressed

  • Existing NDE technologies such as ultrasound can assess changes in pipe wall thickness. But ultrasound cannot detect dealloying, which alters the composition and mechanical properties of the pipe, but not wall thickness
  • A need exists for a completely non-destructive and cost-effective method to assess and monitor the extent of de-alloying in metal pipes

Competitive Advantages

  • Can sensitively delineate between stages of dealloying
  • Solid state probe provides very stable measurements on all surface finishes in any orientation with no leakage
  • Can be used with any DC or AC electrochemical method

Patents

  • US Provisional Patent No.62/655,932