| AVS 59th Annual International Symposium and Exhibition | |
| Advanced Surface Engineering | Monday Sessions |
| Session SE+NS-MoM |
| Session: | Nanostructured Thin Films and Coatings I: Interface Aspects |
| Presenter: | S. Ek, Picosun, Finland |
| Correspondent: | Click to Email |
Corrosion-related problems have always been a major challenge in various industries because of the components’ shortened lifetime. Huge efforts are being made to improve the current corrosion protection procedures and to develop new corrosion preventing techniques. The objective is to find more efficient, environmentally sustainable, and cost-effective solutions for advanced corrosion protection of materials. However, in some applications it is not only corrosion protection that is needed but also wear resistance is required.
Relatively thick PVD coatings are generally used in applications where wear resistance is required. However, achieving simultaneous corrosion protection with that kind of coatings is challenging because the coating doesn’t grow conformally and uniformly enough on the nano/microscale details of the surface of the protected material. This is where ALD coatings are needed: they enable reliable, long-term corrosion resistance through dense, uniform and conformal layers and they block the possible cracks, pinholes and nano/microscale voids and irregularities of the PVD layer, thus improving and securing the performance of the PVD coatings. At the same time, ALD contributes to structural strengthening and better chemical stability.
The choice and composition of the ALD coatings for corrosion protection depend on the substrate material and the kind of environmental conditions to which the protected components are exposed. Especially, certain metal oxides or their laminates or mixtures deposited by ALD form efficient and functional corrosion protection layers. Optimization of the protective thin film thickness and composition has been performed during the last three years in the European Union 7th Framework Program collaborative project CORRAL (“Corrosion protection with perfect atomic layers” [CPFP213996-1]).
In the present work, high-quality coatings with less than 0.001 % porosity were achieved. The coatings were able to seal 100Cr6 steel substrates for over 800 h in neutral salt spray tests (NSS). The lifetime of 3D test components was increased by a factor of 3-10 depending on the substrate material.