Finnish thin film coating specialist Picodeon Ltd Oy has developed its ultra-short pulsed laser deposition (USPLD) surface coating technology to be able to create either porous or dense aluminium oxide (Al2O3) coatings on heat-sensitive substrates for use in a wide range of industrial metallisation applications.

Porous Al2O3 layers are used for instance as filters and electrical insulation layers. Dense Al2O3 is used as a barrier layer and is also an excellent optical coating with high transmittance properties.

The Picodeon process enables precise micro-structural control of Al2O3 coatings, and therefore coating characteristics, by the simple management and maintenance of coating process parameters on Coldab® Series4 USPLD batch process coating equipment.

“This development has enormous potential for new applications of dense and porous aluminium oxide coatings on heat sensitive materials,” said Picodeon VP Sales and Business Development Marko Mylläri. “It is currently very difficult to achieve these results using physical vapour deposition (PVD), sputtering or chemical vapour deposition (CVD) surface coating technologies.”

The Coldab® Series4 equipment has built-in online plasma monitoring and laser power measurement that enable very precise management of coating process parameters, as well as a PC controlled automation that records the actions of the coating process.

The metrics provided by these systems mean that the coating process, and especially the thin film quality, can be controlled with great accuracy to achieve coating characteristics within highly targeted parameters.

Test production runs, for example, showed that the system could improve the porosity of a 3µm Al2O3 coating, for example, from 10 percent to as much as 45 percent by tuning the scanning speed and laser power repetition rate.

Al2O3 coatings on heat-sensitive materials

The Al2O3 coatings were applied on heat-sensitive polyethylene (PE) and thermoplastic polyurethane (TPU) polymer film substrates. This is possible due to the low process temperatures required for surface coating using Picodeon’s Coldab® USPLD system – one of the major benefits of the process.

In addition to Al2O3, the new Picodeon process technology can be used for other coatings as well. Picodeon has produced metallic coatings using Au and Cu, and oxides such as TiO2.

Picodeon’s recently released ColdAb Series4 equipment is currently being installed in commercial applications, and the company is continuing development to industrialise its USPLD processes and tools towards even larger scale volume production capabilities.