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Ferromagnetic Fe-Cu Coating for Ferrous Contaminants Sensing in Aqueous Media

Abou Hewelle, Abdullah
A Master of Science thesis in Mechanical Engineering by Abdullah Abou Hewelle entitled, “Ferromagnetic Fe-Cu Coating for Ferrous Contaminants Sensing in Aqueous Media”, submitted in November 2020. Thesis advisor is Dr. Mehdi Ghommem and thesis co-advisor is Dr. Abdul Hai Al Alami. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
This work investigates the development and analysis of a novel resonant sensor for ferrous contaminations in aqueous media. Resonant sensor is a class of sensors that employ a structure vibrating at resonance. Hence, the proposed sensing device works on the principle of detecting the dynamic response of a vibrating beam resulting from the attraction of iron contaminants present in aqueous solutions to its surface. The ferromagnetic property of the Fe-Cu bimetallic alloy is utilized to capture the contaminants as it is applied as a coating layer on aluminium components. The synthesis of the ferromagnetic material and the coating process were carried out in a planetary ball mill which allows the formation of a homogenous coating layer at low operating temperatures. Microstructural characterization tests, including XRD, SEM and EDS, were performed to confirm the formation of the single-phase Fe-Cu alloy and inspect the structural features of the coating layer. A series of experiments was conducted to examine the quality of the deposition of the coating material and select the optimum synthesis process parameters. Experimental results revealed a successful deposition of a 499 nm thickness layer of the Fe-Cu alloy on the aluminum substrate after coating for 5 hours at a rotational speed of 600 rpm. The produced coated beam samples have the ability of carrying a maximum of 7 mg of iron powder. An experimental set-up, comprising a mini shaker, a laser distance sensor, and a function generator, was built and used to investigate the proposed sensing mechanisms and validate the developed mathematical continuous model for beams fully immersed in fluid media subject to base excitation. This model was also used to generate the frequency responses of the coated beam in different fluid media and predict the change in its dynamic response resulting from the added mass when exposed to iron contaminants in water showing a 0.1 Hz shift in natural frequency due to added mass equivalent to 2% of the mass of the beam.
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