Corrosion can cause devastating damage to materials, and to protect materials from corrosion is crucial, especially in the aeronautical industry. An electroplated Zinc-Nickel coating provides excellent corrosion protection of steel. Electroplating of ZnNi is a sensitive process which needs frequent and fast feedback controls and adjustments of the process electrolyte. A common process control for electroplating processes is the Hull cell test, which is investigated in this study. The Hull cell test is a lab scaled electroplating unit, which spans a wide range of current densities. It is crucial to establish the relation between process parameters in the Hull cell and the resulting coating characteristics in order to implement it as a process control. The purpose of this study is to establish these relations for the ZnNi electroplating process, and evaluate if the Hull cell test is a suitable process control for this process. How the process parameters; current density, temperature, metal ion concentration, and carbonate contaminations affect the coating characteristics; visual appearance, thickness, composition, surface structure, and phase content has been established. Influence on the coatings were mainly seen at current densities higher and lower than the ones used in production. This demonstrates the strength of the Hull cell test for early detection of process deviations. Coating thickness and composition was measured with X-ray fluorescence. However, the composition values for thin coatings were discovered to be inaccurate, which was avoided by increasing the plating time. Once addressed, the Hull cell test is suitable as a process control for the electroplating process of ZnNi.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-202210 |
| Date | January 2024 |
| Creators | Hägg, Elin |
| Publisher | Linköpings universitet, Tunnfilmsfysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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