An investigation of accelerated atmospheric corrosion of copper by using a four-point- probe method and the Scanning Electron Microscope (SEM) is described An aggressive atmosphere containing 100ppm of H2Sand a relative humidity (RH) above MYko was used to accelerate the corrosion process under a controlled environment. The test consisted of two container testing, in triplicate, 25~m thick copper wire. The inhibited samples showed less increases in the measured voltage than the specimens not inhibited. The decrease in the voltage could be correlated to the corrosion rate and the efficacy of the VCI. The SEM images revealed different surface changes in the oxide formation on the protected and non- protected copper surface. We expect that this test presents a possible alternative to existing test methods, i.e. Japanese and German based on the commonly used Federal Test Method 4031, 101C a.k.a. Vapor Inhibiting Ability of VCI Vapors (VIA). Both the VIA test and this test are quite simple to conduct, ?however, quantitatively which is not possible with the VIA.
Volatile Corrosion Inhibitor (VCIS) are increasingly gaining more and more acceptance in industrial and consumer applications. Uses are widespread from water treatment to oil and gas line production to packaging, electronics, artifact procurement and a host of other uses. In recent years there have been several studies aimed at revising and updating the methods to test for the efficacy of VCIS and their detection of them on a surface.1%Success has been quite good for the detection of VCIS and also measuring the efficacy of them in harsh environments. l? 214There is though a desire for a simpler way to accomplish the same goal, Industrial users do not always have the sophisticated equipment and the facilities like a research laboratory to determine if there is a VCI on the surface or even to determine if a host of a VCI is efficient as a VCI carrier. For most companies the only method to test a VCI, i.e. crystals, liquids, or paper/polyethylene or other carriers of VCIS was to use a test method developed over 15 years ago called the Federal Test Method 4031, 101C a.k.a. Vapor Inhibiting Ability of VCI Vapors (via)? or similar methods which follow the same procedure.
The test method has come under some criticism due to the procedure of testing and due to the evaluation guidelines. They have been criticized because of it?s poor reproducibility and inconsistency of results. Here area few of the criticisms of the test method: There are inherent problems associated with this method such as the condensation portion of the test. In this portion of the test, Section 6.1.1.3, states, ...Cold water at a temperature 40 F below ambient shall be added to the aluminum tubes until full. After 3 hours, the water shall be removed from the steel tubes and the steel specimen evaluated for evidence of rust... The condensation part of this testis in part erroneous due to the very fast thermal dynamics changes experienced in the metallic substrate. The shock value to the specimen is difficult to reproduce and can sometimes change depending on the metal specimen preparation. The test method also does not fully outline polishing method which properly cleans the surface of the samples.
Alodan and Smyrl10have described a very thorough method for cleaning the surface of aluminum, which can also be applied towards other metals, after polishing using an ultrasonic cleaner. This method addresses cleaning out the embedded particles within the peaks and valleys experienced during polishing. The VIAmethod only recommends wiping with surgical cloth and dipping the part into hot mineral spirits followed with a boiling methanol dip. This method can be dangerous as
