Although producing clusters by physical methods offers many benefits, low deposition rates have prevented cluster beam deposition techniques from being adopted more widely. The influence of the gas aerodynamics inside the condensation chamber of a magnetron cluster source on the cluster throughput is reported, leading to an improved understanding of the gas aerodynamics' influence on cluster transport. In the first part of the paper the influence of the carrier gas' inlet position on the cluster flux is studied. In particular, two inlet configurations were investigated, i.e. from the rear of the chamber and from within the magnetron sputtering source. It was found experimentally that the latter configuration can lead to an increased cluster flux, under the same conditions of gas
Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects, cluster-support interactions, and reaction mechanisms of cluster materials. Although the wet chemistry method has been widely used to synthesize nanoparticles, the gas-phase synthesis and size-selected strategy was the only method to prepare supported metal clusters with precise numbers of atoms for a long time. However, the low throughput of the physical synthesis method has severely constrained its wider adoption for catalysis applications. In this review, we introduce the latest progress on three types of cluster source which have the most promising potential for scale-up, including sputtering gas aggregation source, pulsed microplasma cluster source, and matrix assembly cluster source. While the sputtering gas aggregation source is leading ahead with a production rate of ∼20 mg·h−1, the pulsed microplasma source has the smallest physical dimensions which makes it possible to compact multiple such devices into a small volume for multiplied production rate. The matrix assembly source has the shortest development history, but already show an impressive deposition rate of ~10 mg·h−1. At the end of the review, the possible routes for further throughput scale-up are envisaged.
Inside
a spacecraft, the temperature and humidity, suitable for
the human crew onboard, also creates an ideal breeding environment
for the proliferation of bacteria and fungi; this can present a hazard
to human health and create issues for the safe running of equipment.
To address this issue, wear-resistant antimicrobial thin films prepared
by magnetron sputtering were developed, with the aim to coat key internal
components within spacecrafts. Silver and copper are among the most
studied active bactericidal materials, thus this work investigated
the antibacterial properties of amorphous carbon coatings, doped with
either silver, silver and copper, or with silver clusters. The longevity
of these antimicrobial coatings, which is heavily influenced by metal
diffusion within the coating, was also investigated. With a conventional
approach, amorphous carbon coatings were prepared by cosputtering,
to generate coatings that contained a range of silver and copper concentrations.
In addition, coatings containing silver clusters were prepared using
a separate cluster source to better control the metal particle size
distribution in the amorphous carbon matrix. The particle size distributions
were characterized by grazing-incidence small-angle X-ray scattering
(GISAXS). Antibacterial tests were performed under both terrestrial
gravity and microgravity conditions, to simulate the condition in
space. Results show that although silver-doped coatings possess extremely
high levels of antimicrobial activity, silver cluster-doped coatings
are equally effective, while being more long-lived, despite containing
a lower absolute silver concentration.
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