Seeking help regarding the standards for evaluating low-temperature corrosion inhibitors

3.1 Gravimetric method? The gravimetric method is the most widely used; it is relatively intuitive and an evaluation approach that is easily accepted by people. Test methods can be divided into static tests and dynamic tests, with dynamic tests further being categorized into laboratory dynamic tests and field dynamic tests. During static tests, both the test specimen and the medium remain at rest. Although this method is simple in terms of equipment and operation, the results obtained often differ significantly from those observed in actual applications. It can be used in the laboratory for the preliminary screening and evaluation of corrosion inhibitors. The results of dynamic tests in the laboratory are relatively close to the actual conditions on site. ? The loss-weighting method can directly measure the corrosion weight loss of metal materials in a corrosive medium, calculate the average corrosion rate over the test period, and thereby determine the corrosion inhibition efficiency. Due to the reliable results obtained by the weight-loss method and its straightforward measurement process, it has become an important technique for evaluating the performance of corrosion inhibitors. The disadvantage of the weightlessness method is that operations such as processing and cleaning the test specimens are quite time-consuming; furthermore, the testing period for systems with a low corrosion rate is long. The weight loss method is only applicable to general corrosion and not suitable for electrocorrosion. ? 3.2 Tafel linear extrapolation method? This is an electrochemical method. First, the polarization curve of the specimen in the corrosive medium is determined. Polarization is carried out until the Tafel linear region is reached; by extrapolating this curve, an intersection with the horizontal line corresponding to the equilibrium potential is found. The current density at this intersection point represents the corrosion current density, which is then used to calculate the corrosion rate based on Faraday’s law. For systems where the anodic polarization curve is difficult to measure accurately, only the cathodic polarization curve is often measured. This method is fast and sensitive, and has been listed as one of the testing methods in the petroleum and natural gas industry standard SY/T 5405-1996 \"Test Methods and Evaluation Criteria for Corrosion Inhibitors Used in Acidizing\". 3.3 Linear polarization method? This is also an electrochemical method that is characterized by high sensitivity and speed, and it is suitable for corrosion systems formed by any electrolyte solution. The principle is that, since there is a linear relationship between potential changes and current changes during micro-polarization, the polarization resistance can be determined, and the corrosion current can be calculated using the B value. If the goal is merely to screen for corrosion inhibitors or to roughly assess their corrosion-inhibiting performance, polarization resistance can be used directly. However, to determine the corrosion rate, other methods are needed to obtain the B value, which is not very convenient; this is also one of the major weaknesses of the linear polarization method. ? Due to the low polarization current, it does not damage the surface condition of the specimen; multiple measurements can be taken using a single specimen, and it is suitable for on-site monitoring. For the same system, assuming that the value of B does not change with the amount of corrosion inhibitor added, it is possible to evaluate the corrosion inhibition effect or calculate the inhibition rate without determining the value of B. ?

DL/T 523—93: Evaluation criteria for the performance of corrosion inhibitors used in hydrochloric acid pickling and methods for immersion corrosion testing. Please refer to http://bbs.hcbbs.com/viewthread.php?tid=141501&pid=615198&page=1&extra=page%3D1#pid615198. Please find the standard number of the standard you need; everyone, please help out:handshake

No standard number? I only know SY/T 5273-2000 and SY/T 5405-1996; I’m not sure if there are any others

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