Electroplated reactive nanoparticle dispersed coatings

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Reactive layer systems are combinations of at least two materials (mostly metals) whose reaction with each other shows a strongly negative enthalpy. State of the art are e.g. Ni-Al multilayers, which are produced by PVD processes. Applications for reactive layers arise in joining technology, where the rapid release of large amounts of heat in a small, well-defined space is required. In this project, particulate reactive layer systems will be produced by electrochemical deposition from ionic liquids (ILs). A special gas phase process will be used for the preparation of nano- to micro-scale particles, in which the particles are obtained as a dispersion in an IL. This dispersion then serves as the basis for an electroplating bath from which the layers are electrochemically deposited. For a reactive Ni-Al system, Ni particles can be dispersed in an Al electrolyte, or Al particles in a Ni electrolyte. Structure-reactivity relationships will be investigated at the deposited layers with various analytical methods (high speed thermography, XRD, FIB, TEM etc.). Among others, the question of how the size and distribution of the particles affect the reaction speed of the layer will be investigated. In the electrochemical preparation process, particular attention will be paid to the stabilization of the particles in the IL and a better understanding of the deposition process. Open questions arise regarding the role of the surface charge of the particles in the IL. Can classical theories for the deposition mechanism of composite coatings in aqueous media describe the process under consideration in this project? Overall, it is expected that the state of knowledge regarding the preparation methods and structure-property relationships of reactive layer systems will be significantly expanded. This basic knowledge will then form the basis for tailoring reactive coating systems for new applications.