Laser driven deposition technology by assisting centrifugal force

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Surface modification and thin film deposition guarantee the functionality, quality and reliability of tools and components and are used in all important industrial areas [1,2]. Whereas conventional physical vapour deposition processes in vacuum are widely used in industry, pulsed laser deposition technology still suffers from a lack in productivity. To compensate for this deficiency, a new technique is using a laser melt-spraying process, where the material is molten with a pulsed Nd:YAG-laser and sprayed off the surface by centrifugal force generated by rotation of the target.The process is established in a low-pressure chamber, but in most cases deposition in open atmosphere achieves good results. The new method yields film growth rates of about 50 μm/s on an area of 4 cm2. The layers are dense and have a good adhesion. The coating structure, however, is rough and can be compared with good thermal spray coatings. The process is suitable for thicker coatings (several 10 μm upto mm-range) of either metals, metal alloys or ceramics with a liquid phase. It is independent of the substrate material which is not exposed to high temperatures.Another variant of this technique uses the target materials laser produced vapour phase to deposit thin layers upto several μm. In this case, undesirable droplets are thrown out of the deposition zone.Potential applications are in the field of wear or corrosion resistance or high temperature tasks. Besides, the suitability of the process to partially deposite layers has to be emphasized.Surface modification and thin film deposition guarantee the functionality, quality and reliability of tools and components and are used in all important industrial areas [1,2]. Whereas conventional physical vapour deposition processes in vacuum are widely used in industry, pulsed laser deposition technology still suffers from a lack in productivity. To compensate for this deficiency, a new technique is using a laser melt-spraying process, where the material is molten with a pulsed Nd:YAG-laser and sprayed off the surface by centrifugal force generated by rotation of the target.The process is established in a low-pressure chamber, but in most cases deposition in open atmosphere achieves good results. The new method yields film growth rates of about 50 μm/s on an area of 4 cm2. The layers are dense and have a good adhesion. The coating structure, however, is rough and can be compared with good thermal spray coatings. The process is suitable for thicker coatings (several 10 μm upto mm-range) of either metals...