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| Abstract No.: |
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Scheduled at:
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Wednesday, May 05, 2021, Hall 1 2:30 PM
Testing and Design
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| Title: |
Corrosion in brazed heat exchanger materials: Measurement techniques for optimised and application specific material designs
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| Authors: |
Fabian Ritz* / Aleris Rolled Products Germany GmbH, Germany
Bernd Jacoby / Aleris Rolled Products Germany GmbH, Germany
Steven Kirkham/ Aleris Rolled Products Germany GmbH, Germany
Marina Cornejo/ Aleris Rolled Products Germany GmbH, Germany
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| Abstract: |
During its lifetime rolled aluminium material used in brazed heat exchanger applications is exposed to a variety of different corrosive media and environments. It has to pass several standardised corrosion tests in order to simulate many years in service. Future drivetrain technologies, e.g. electric vehicles or fuel cell technologies, combined with the general trend towards lighter weight constructions using thinner gauged materials, lead to more challenging conditions for brazed heat exchanger materials and for the design of the heat exchangers themselves. As a consequence, a better understanding of corrosion mechanisms and the open circuit potential (OCP) differences, which can result from local chemistry and microstructural changes are becoming increasingly important elements when designing heat exchanger materials. This paper summarises recent R&D activities on finding stable best practices for sample preparation and OCP measuring techniques on aluminium surfaces and high resolution profiles through material thickness. Results of collected data, in combination with a wide variety of alloys, enables the targeted identification and adaption of material solutions for any specific current and future application. The capabilities to produce complex four or five layer multi-clad brazing sheets using inter-liners, opens up the possibilities for new material designs. Bespoke inter-liners controlled in terms of chemistry and thickness can act as localised diffusion barriers as well as sacrificial corrosion layers. Additional goals of this paper are to prevent confusing and conflicting results for customers with regards to OCP interpretation and usage, and to promote industry best practice.
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