Abstract: A method of detecting a locally generated corrosion of a first metal element when exposing the first metal element (2) to a corrosive environment. A first surface of the first metal element (2) is exposed to the corrosive environment. A sponge (3) is sandwiched between the first metal element (2) and a second metal element (4). The sponge (3) constituting in dry state an electrical insulator and constituting an electrical conductor when wetted in the corrosive environment. An electrical insulator together with the first metal element (2) encapsulates the second metal element (4) and the sponge (3) for preventing the second metal element (4) and the sponge (3) from being directly exposed to the corrosive environment. An impedance between the second metal element (4) and a ground electrode is measured, and a decrease in the impedance from an infinite impedance to a finite impedance caused by a pinhole being generated in the first metal element (2) is monitored.

Abstract: A method of detecting a locally generated corrosion of a first metal element when exposing the first metal element (2) to a corrosive environment. A first surface of the first metal element (2) is exposed to the corrosive environment. A sponge (3) is sandwiched between the first metal element (2) and a second metal element (4). The sponge (3) constituting in dry state an electrical insulator and constituting an electrical conductor when wetted in the corrosive environment. An electrical insulator together with the first metal element (2) encapsulates the second metal element (4) and the sponge (3) for preventing the second metal element (4) and the sponge (3) from being directly exposed to the corrosive environment. An impedance between the second metal element (4) and a ground electrode is measured, and a decrease in the impedance from an infinite impedance to a finite impedance caused by a pinhole being generated in the first metal element (2) is monitored.

Abstract: The present invention relates to a method and an apparatus for measuring accumulated and instant rate of material loss or material gain of metal elements for the detection of metal deposition (material gain) caused for example during deposition of coatings used in plating processes and corrosion (material loss) caused for example in pipelines during transportation of hazardous media. The apparatus and the method provides means for measuring accumulated and instant rate of material loss or material gain by inserting a probe in a measurement environment causing a probe experience metal deposition or corrosion. Further the apparatus and the method provides means for performing a temperature independent measurement of accumulated and instant rate of material loss or material gain accomplished without use of a temperature sensor device.