Studies in the Discontinuities in Electrodeposited Metallic Coatings
| Autor: | U. R. Evans, S. C. Shome |
|---|---|
| Rok vydání: | 1950 |
| Předmět: |
Electrolysis
Materials science Metallurgy Metals and Alloys chemistry.chemical_element Surfaces and Interfaces Electrolyte Overpotential Condensed Matter Physics Cathode Surfaces Coatings and Films law.invention Metal Nickel chemistry Mechanics of Materials law visual_art visual_art.visual_art_medium Composite material Current density Cobalt |
| Zdroj: | Transactions of the IMF. 26:137-167 |
| ISSN: | 1745-9192 0020-2967 |
| Popis: | SummarySome possible causes of discontinuities in nickel and cobalt deposits have been investigated. The results suggest that neither hydrogen bubbles clinging to the surface of the cathode, nor impurities present on the surface of the basis metal (including those deposited from the electrolyte during electrolysis) can be main causes of pores. The important cause appears to be the surface contour of the basis metal. Work is proceeding to decide whether internal stresses in the deposit or in the basis metal can cause discontinuities.Changes of current density or pH in nickel baths were not found to influence the number of pores in the deposits, but a rise in temperature of the bath increased the number of pores per unit area.Cathode polarisation curves for nickel and cobalt deposition from different solutions showed a high value of dη/dI to be associated with a small number of pores, where η is the overpotential and I the current density. Concentration polarisation was observed when nickel was deposited fr... |
| Databáze: | OpenAIRE |
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