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2023
Conference Paper
Title
Vacuum Deposition of Aluminum Alloys with 1 µm/s on Different Types of Semi-finished Products
Abstract
Electron beam physical vapor deposition (EB-PVD) with high power axial EB guns allows for high coating rates and therefore it is predestinated when comparatively thick coatings shall be deposited with high throughput in mass production processes. The top sliding layer on bearing shells is an excellent applica-tion case. In low-cost manufacturing technologies, often semi-finished products such as sheets or strips are coated, from which the final products are manufactured which can exhibit quite a broad range of dimensions.
The adaptation of related processes such as pretreatment and substrate cooling of three different semi-finished products was the focus of the investigations. All process steps were optimized for high throughput. The depositions with AlSn or AlSnCu al-loys were carried out at coating rates up to 1 µm/s. These alloys with components of different vapor pressures were evaporated out of one continuously fed crucible with long-term stability. The layers revealed a very fine distribution of tin clusters in the aluminum matrix. The tin clusters had dimensions in the range of 200 to 400 nm. This grain size range was a direct conse-quence of the high coating rate; it is thus process-specific for EB-PVD. Such coatings are highly beneficial for applications such as plain bearings. Initial stress tests have impressively con-firmed the advantages for EB-PVD processed bearings.
The adaptation of related processes such as pretreatment and substrate cooling of three different semi-finished products was the focus of the investigations. All process steps were optimized for high throughput. The depositions with AlSn or AlSnCu al-loys were carried out at coating rates up to 1 µm/s. These alloys with components of different vapor pressures were evaporated out of one continuously fed crucible with long-term stability. The layers revealed a very fine distribution of tin clusters in the aluminum matrix. The tin clusters had dimensions in the range of 200 to 400 nm. This grain size range was a direct conse-quence of the high coating rate; it is thus process-specific for EB-PVD. Such coatings are highly beneficial for applications such as plain bearings. Initial stress tests have impressively con-firmed the advantages for EB-PVD processed bearings.