Stirred-Reactor Coupon Analysis: An International Round Robin Study

Joseph V. Ryan, Scott K. Cooley, Benjamin P. Parruzot, Joelle T.G. Reiser, Claire Corkhill, Du Jincheng, Karine Ferrand, Stéphane Gin, Mike Harrison, Yaohiro Inagaki, Christoph Lenting, John Mccloy, Seiichiro Mitsui, Michelle Snyder, Nicholas Smith, Matthew R. Asmussen, Gary L. Smith

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Abstract

The objective of this work was to determine the precision of the Stirred-Reactor Coupon Analysis (SRCA) method when used to determine the dilute condition corrosion rate. To this end, an inter-laboratory round robin study was conducted per the instructions in ASTM Practice E691 to measure the precision with which the SRCA test method can be conducted. Twelve independent labs from eleven different institutions each evaluated four glass compositions in three different conditions. The ASTM procedures recommend at least 6 labs participate in a round robin testing the same 3 materials in the same conditions to determine precision. In this case, 12 labs each performed 12 independent tests. This was only possible thanks to the multi-glass testing capability of the SRCA test. A total of 108 duplicate pairs were used to calculate the repeatability of the tests, with the same glass tested in the same vessel, producing as identical conditions as possible for the replicates. These test results were quite tightly clustered, with a median difference from the average value of the pair of only 2.8%. Based on the calculations recommended in the ASTM E177-20 procedure and the repeatability standard deviation (sr) of 8.13%, the test repeatability limit (r) was calculated to be precise within 21.8% of the expected value with 95% confidence level. The reproducibility limit (R) of the test was examined using all 287 data points from the round robin. Because of the differences in dissolution rates due to pH variability and intrinsically for the 12 conditions tested, the reproducibility limits for each condition and overall were calculated from the percent relative residual value for each test. Using the ASTM calculations for reproducibility, the SRCA test was calculated to be precise within 53.3% of the expected value with a 95% confidence level.
Original languageEnglish
PublisherPacific Northwest National Laboratory
Number of pages99
StatePublished - 1 Sep 2022

Publication series

NamePNNL reports
PublisherPacific Northwest National Laboratory
No.PNNL-33141 - RPT-IGTP-027

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