Surface treatment of aluminium with a 10kW CO2 laser

Abstract

Aluminium alloys win as construction material more and more importance. But for many applications it is necessary to cover the surface of the aluminium substrate with a protective layer against wear or corrosion. With the CO2 laser it is possible to put on such coatings on aluminium substrates in one-step or two-step processes. This work shows the difficulties in the two-step process of AIMgSi alloys, where it is coated by high velocity flame spraying and electroplating systems in the first processing step. At the one-step process the prefixed layer is dropped by another method wich means that the coating powder is put on simultaneously with the laser treatment. With this method, under special consideration of the used shielding gas and powder feeding, load bearing coatings with no formation of cracks and pores are produced as single and overlapping traces. By using AIMgSi alloys as base material and Ni-base alloys as coating materials there yield many advantages for the one-step process in reference to the industrial processing and economical aspects.Aluminium alloys win as construction material more and more importance. But for many applications it is necessary to cover the surface of the aluminium substrate with a protective layer against wear or corrosion. With the CO2 laser it is possible to put on such coatings on aluminium substrates in one-step or two-step processes. This work shows the difficulties in the two-step process of AIMgSi alloys, where it is coated by high velocity flame spraying and electroplating systems in the first processing step. At the one-step process the prefixed layer is dropped by another method wich means that the coating powder is put on simultaneously with the laser treatment. With this method, under special consideration of the used shielding gas and powder feeding, load bearing coatings with no formation of cracks and pores are produced as single and overlapping traces. By using AIMgSi alloys as base material and Ni-base alloys as coating materials there yield many advantages for the one-step process in reference to t...