Changing the Sizes of Details Made of Aluminum Alloys during Microarc Oxidation Process

Abstract

It is shown that microarc oxidation (MAO) makes it possible to increase the size of aluminum alloy details by forming dense ceramic coatings (MAO-coatings) on them. Found that MAO-process a duration of 50...80 minutes in a liquid solution according to conventional technology allows you to increase the size of the details made of deformable alloy AMg3 and D16 by 78...80 % of the thickness formed on them MAO-coating and MAO-process in solution of corundum particles opens the possibility of increasing the same details by 98...100 % of the thickness formed on them more thick MAO coating. Revealed that increasing solution temperature from 15 to 45 оС leads to a reduction in the thickness of MAO coating and an even more significant reduction in growth dimensions, as well as to reduce the quality of their surfaces. It is shown that the removal of the outer layers of MAO coatings to a thickness of 20 ... 25 μm by grinding contributes to a significant reduction in the roughness of the surfaces of details. It is confirmed that MAO coatings obtained in liquid solution and in solution with corundum particles have a similar mainly polycrystalline structure, but MAO coatings obtained in solution with corundum particles differ in greater thickness and higher corundum content (α-Al2O3). It is established that the outer layers of MAO coatings are characterized by a relatively low content of modifications of crystalline aluminum oxide, so after their removal, the strength properties of the surfaces of details also improve. The principal possibility of increasing the size of details made of deformable aluminum alloys by 150 μm with ensuring high quality of their surfaces is proved.