Effect of acid immersion on RTV silicone rubber coatings in inclined plane tests

The paper presents the results of an investigation into the effect of acid immersion on the aging of room temperature vulcanized (RTV) silicone rubber coatings in inclined plane tests (IPT). Two commercial coatings, RTV-A filled with ATH (aluminum tri-hydrate) and RTV-B filled with silica, are compared before and after acid immersion. Acid aging consists of immersing the samples in 3.9 pH nitric acid at a temperature of 90/spl deg/C for 2 weeks. The relative comparison between the two samples is based on the development of the fundamental and third harmonic of the leakage current during IPT tests, eroded area, the time to failure and SEM microphotographs. All of these observations show that acid rain damages RTV-A more severely than RTV-B. However virgin ATH filled sample showed a better performance compared to the silica filled material.