1. No category

8.
ADVANCED LASER-ASSISTED COATING TECHNIQUES
Wolfgang Waldhauser
JOANNEUM RESEARCH, INSTITUTE FOR SURFACE TECHNOLOGIES AND PHOTONICS, LEOBENNIKLASDORF, AUSTRIA
Abstract
The first laser systems for generating coherent monochromatic light were built in the early
seventies of the 20th century. Today, the laser light is used in various areas, such as
manufacturing technology, medicine, instrumentation, communication equipment, consumer
electronics, computer engineering, nuclear engineering and military technology. In the field of
surface engineering lasers are applied for marking and structuring, surface hardening,
cleaning and stripping, activating and for depositing of coatings and laser alloying.
At the Institute for Surface Technologies and Photonics of JOANNEUM RESEARCH
technical solutions are worked out in cooperation with industrial partners and laser processes
for applying thick wear resistant coatings and laser-assisted thin-film technologies have been
developed and up-scaled to the production stage. An example for laser cladding is the coating
of drill pipes in the oil industry, which can be applied up to 12 meters long components today.
For thin film deposition the so-called pulsed laser deposition (PLD) is used. In this laserassisted coating process the coating material is evaporated with pulsed laser radiation in a
vacuum chamber. Depending on the process this material in the gaseous state can react with
other added reactive gases and forms on the surface of the substrates films with coating
thicknesses of a few nanometers to a few micrometers. Pulsed Laser Deposition (PLD) has
been demonstrated as a suitable coating technique for a wide range of coating materials, e.g.
metals, oxides, nitrides, carbides and diamond-like carbon. It exhibits outstanding process
features which can be the basis for innovative applications in future. The most relevant
process features of PLD are the low possible substrate temperatures (20 - 100°C) and the
resultantly low thermally induced distortion of substrates, the avoidance of thermally induced
microstructural changes in the substrate material, an excellent film adhesion and the
avoidance of pollutant emissions. Potential fields of application include coating of
temperature sensitive and non-conducting substrates, production of mono- and multi-layer
coatings with tailored structure, e.g. tribological and corrosion protection coatings, functional
coatings for electronic, optical, sensoric and medical purposes, adhesive layers. Further
- 109 -
Trajnostne tehnologije kovinskih materialov – Sustainable Technologies of Metallic Materials
opportunities are also created by the combination with conventional coating methods (hybrid
process), such as magnetron sputtering.
In the lecture, these laser-assisted methods will be presented with their advantages and
disadvantages and examples of practical application will be shown.
- 110 -