AGODCO Group

EIS tests were to validate the claim that Stealth-Lock MIF does not affect the compliant integrity of the FBE ID pipe coating. Electrochemical Impedance Spectroscopy (EIS) has been proven to be a powerful quantitatively and non-destructive technique in the understanding and characterization of protective coatings.

NACE TM0177 (SSC), ISO 3183 & API 5L (TENSILE & HARDNESS), ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) - MATERIAL & CORROSION

Electrochemical Impedance Spectroscopy (EIS)
One of the more common Electrochemical Impedance Spectroscopy (EIS) -derived parameters used to qualify the degree of corrosion protection provided by an organic coating has been the pore resistance (RPO), coating capacitance CC, corrosion resistance (RCORR), or a similar measure of the barrier property or corrosion rate of the coated substrate.

Sulphide Stress Cracking (SSC) NACE TM0177
SSC occurs in sour service applications under the combined action of tensile stress and corrosion in aqueous environments containing hydrogen sulphide (H2S). Stealth-Lock SSC test results are indicative that Stealth-Lock MIF does not adversely affect the integrity of the pipeline when used in conjunction with compliant FBE ID coatings. The external and internal surface of the Stealth-Lock specimens are stressed and the applied stress of 90% AYS determined via strain gauges. The specimens are then exposed to a sour environment for a 30-day period.

Test solution ‘A’ with reagent grade oxygen-free nitrogen and 99.5% minimum purity hydrogen sulphide gas (H2S) is used for the tests. The test water is distilled or de-ionised, conforming to ASTM D1193-Type IV. Following the specified test period the specimens are initially inspected at x10 magnification for evidence of cracking. Any suspect indications observed during visual examination are categorized by metallographic examination.