Canadian Finishing and Coatings Manufacturing: Nov/Dec 2022 - 20

INDUSTRIAL FINISHING: AEROSOL DEPOSITION
been accelerated through a nozzle. During the impact the powder
particles crack and form a very dense (>>99 per cent), smooth
coating with very high adhesion to the substrate.
The substrate material is of neglectable influence. The method
works on ceramics, metals, glass, semiconductors, and even hard
plastics. Aerosol deposition is even more flexible regarding the
coating materials themselves. Any type of ceramic can be used
in pure form or intermixed with other ceramics in any thinkable
ratio to tailor electrical, mechanical, and thermal properties.
Metals can be added to further broaden these property ranges,
and even organic substances can be added. Conventional
methods such as thermal plasma spray, evaporation, sputtering,
CVD, ALD or MOCVD are often not able to produce the required
thicknesses or physical properties within a reasonable time span
or at acceptable costs.
Ceramic
Coatings at Room
Temperature
Heraeus High Performance Coatings
commercialised aerosol deposition for
various industries and applications
Aerosol deposition itself is nothing new-it was discovered
in Japan two decades ago. For a long time, it was mainly found
in the academic environment not embracing its versatility with
respect to potential applications. Heraeus High Performance
Coatings has continuously improved this technology to make it
available for numerous industries. To date, the technology has
been perfected to 24/7 operation which makes it attractive for
many markets and applications.
Under the brand name Coatastic, Heraeus offers feasibility
BY BASTIAN EBELING
C
20
eramic coatings have garnered increasing attention
over the past years as industries undergo massive
changes or continue to improve the quality of their
products. Prominent examples are automotive where
electrification calls for electrical insulation where it was not
needed before, the semiconductor industry where node reduction
requires more refined etch resistant coatings in the plasma
etch chambers, and (power) electronics where miniaturisation
requires enhanced electric insulation and thermal management
properties.
This is where aerosol deposition excels. It allows companies
to manufacture these ceramic coatings at room temperature,
using rough vacuum, without hazardous materials and at high
velocity, making it a cost-effective and eco-friendly solution. The
basic principle behind Aerosol deposition is room temperature
impact consolidation. The coating material provided in form of
a powder and a carrier gas such as O2, N2 or noble gases form an
aerosol. This aerosol hits the substrate at high speed after having
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studies, development and coating services, standardized R&D
chambers as well as customised production equipment.
Ilka Luck, head of the business unit at Heraeus, points out
the significant advantages of aerosol deposition in e-mobility
applications, as protective coatings and in the semiconductor
industry. In e-mobility parasitic currents may significantly
shorten the lifetime of components due to electro-corrosion.
As neither surface treatments before the coating nor polishing
after the coating are required, thin ceramic coatings can be easily
applied by aerosol deposition to prevent this damage.
Ceramic coatings by aerosol deposition also help protect
surfaces against corrosion, scratches, and abrasion. One
prominent example is alpha-alumina on NiCrAlY. The coating
very effectively suppresses corrosion at high temperatures (1200
deg C and above) of these alloys.
Etch-resistant coatings in plasma etch chambers for
semiconductor manufacturing are one sub-section of protective
coatings where aerosol deposition as a method is already well
established. As the miniaturisation of semiconductor devices
continues the production equipment needs to get more and
more sophisticated. Equipment lifetime as well as production
throughput are under scrutiny. Thus, the demand for aerosol
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Canadian Finishing and Coatings Manufacturing: Nov/Dec 2022

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