@PhdThesis{dbt_mods_00026038,
  author = 	{Hahn Dr.-Ing., Sebastian},
  title = 	{Grundlagenuntersuchungen zur Wirkweise und Kontrolle von Katalysatoren in autokatalytischen B{\"a}dern zur Metallabscheidung},
  year = 	{2015},
  month = 	{May},
  day = 	{21},
  keywords = 	{Str{\"o}mungszelle; RDE; QCM; NiP; autokatalytische Abscheidung; Stabilisatoren; Blei; Thioharnstoff; galvanostatische Aufl{\"o}sung},
  abstract = 	{In this work, a flow cell for in-situ microgravimetrical and
electrochemical investigationsis introduced and characterized. The well
understood homogeneous diffusionboundary layer of a rotating disk electrode
(RDE) is well suited for the study of electrochemicalprocesses, but the
in-situ measurement of layer thickness is not possible.This parameter is
important for the characterization of deposition processes and canbe
measured with a quartz crystal microbalance (QCM), but rotation for
generating ahomogenous flow and diffusion boundary layer is hardly
feasible. Instead, we builda combination of a flow cell with a QCM to allow
the investigation of diffusioneffects on electrochemical metal deposition
speed.For the flow cell design and optimization, the ``Comsol
Multiphysics`` software wasused to calculate flow conditions and
concentration gradients at the electrode. Calculationresults were checked
by measuring current limiting density values of theredox system
Hexacyanoferrat II/III in our flow cell/QCM combinations and comparingthem
to values obtained with an RDE.The main application of the experimental
assembly is the characterization of theautocatalytic NiP-deposition. In
this process, stabilizers are used to prevent the spontaneousdecomposition
of the electrolyte. The inhibition of the deposition rate as afunction of
stabilizer concentration and its dependence on flow conditions is
examined.Lead and thiourea are used as stabilizers in this work.In the same
experimental arrangement, the electrochemical dissolution potential ofthe
previously deposited NiP-layer was measured in a variety of dissolution
electrolytes.It was found that the NiP-layer's dissolution potential is
influenced by the typeof stabilizer, its concentration and the flow
conditions during the deposition step.After optimizing the dissolution
electrolyte, the measurement of the dissolutionpotential allowed the
estimation of the thiourea concentration in the depositionelectrolyte in a
range between 0-0,5 ppm and >1 ppm.},
  url = 	{https://www.db-thueringen.de/receive/dbt_mods_00026038},
  url = 	{http://uri.gbv.de/document/gvk:ppn:825836867},
  file = 	{:https://www.db-thueringen.de/servlets/MCRZipServlet/dbt_derivate_00031780:TYPE},
  language = 	{de}
}