Comparison of abrasive tests for transparent optical coatings

Many standardised abrasion tests are available but not all are appropriate for transparent coatings. Therefore we had a closer look at two methods in this study: we used the oscillating sand method and the sand trickling test for a series of different samples. The first one is like a hard grinding and the second one is an impact test. Also adequate techniques have to be applied for the determination of abrasion. We executed haze measurements as well as ellipsometry. The hardness and size of the test media influences the damage. Thus two types of test media were utilised: silica and corundum. The results of the abrasive tests are compared to the hardness of the coating materials.