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@PHDTHESIS{Koch:826737,
      author       = {Koch, Denise Silke},
      title        = {{E}ntwicklung selbstheilender {W}ärmedämmschichten},
      volume       = {355},
      school       = {Universität Bochum},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2017-00955},
      isbn         = {978-3-95806-201-6},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {X, 120 S.},
      year         = {2016},
      note         = {Universität Bochum, Diss., 2016},
      abstract     = {The presented work is dealing with the manufacturing of
                      self-healing thermal barrier coatings by atmospheric plasma
                      spraying that are applicable in high temperature processes
                      with thermal loading. The turbine blades of gas turbines for
                      example, experience thermal stresses that are induced into
                      the thermal barrier coatings and can cause crack
                      development. After a certain time these cracks grow and lead
                      to a spallation of the coating. By this, the turbine blade
                      would not be protected any more. With the integration of a
                      self-healing process, the time between maintenances can be
                      extended to save operational costs. The basic idea to
                      realize such self-healing coatings is the integration of
                      MoSi$_{2}$ as self-healing particles. The oxidation of
                      MoSi$_{2}$ leads to the formation of SiO$_{2}$ that can
                      infiltrate cracks and seals them. This can prevent the
                      spallation of the coating. The presented work was performed
                      within a project named SAMBA (self-healing thermal barrier
                      coatings) that was funded by the European Union. The first
                      step in the production of a self-healing thermal barrier
                      coating was the integration of MoSi$_{2}$ particles into a
                      coating. Yttria stabilized zirconia (YSZ) was used as
                      coating matrix since this is the state of the art material.
                      Due to a decomposition of the MoSi$_{2}$ when spraying it at
                      conditions that are needed to produce coatings made out of
                      YSZ, the manufacturing of a homogeneous mixed coating of YSZ
                      and MoSi$_{2}$ from a powder mixture of both materials was
                      not possible. This problem was solved by using a second
                      injection point located at a distance from the
                      plasma-torch-exit. Nevertheless the coatings made out of YSZ
                      and pure MoSi$_{2}$ were not suitable to work as a
                      self-healing thermal barrier coating due to the fact that
                      the oxidation of MoSi$_{2}$ was not controlled. The volume
                      expansion caused by the formation of SiO$_{2}$ induces
                      stresses into the coating that lead to a failure and the
                      spallation of the coating. The second step in the
                      development was to encapsulate the MoSi$_{2}$ particles with
                      Al$_{2}$O$_{3}$, as this encapsulation was supposed to work
                      as a protection against a premature oxidation of the
                      MoSi$_{2}$. As the spraying process leads to a deformation
                      of the particles during deposition on the substrate, a
                      pre-encapsulation of the powder would be destroyed. Because
                      of this, the encapsulation has to be formed in-situ within
                      the coating. Several coatings were produced using Al doped
                      MoSi$_{2}$ to integrate it into the YSZ coatings. These
                      coatings were heat treated and by this several requirements
                      were determined that need to be fulfilled in order to enable
                      the self-healing process. Coatings that have been produced
                      using spraying parameters, that enable the fulfillment of
                      these requirements, and these coatings resulted in an
                      improvement of the lifetime of the coatings compared to
                      standard YSZ coatings. Within the SAMBA project further
                      analysis and investigations will be performed to be able to
                      judge on the self-healing abilities of coatings produced by
                      the procedures described in this work.},
      cin          = {IEK-1},
      cid          = {I:(DE-Juel1)IEK-1-20101013},
      pnm          = {113 - Methods and Concepts for Material Development
                      (POF3-113) / HITEC - Helmholtz Interdisciplinary Doctoral
                      Training in Energy and Climate Research (HITEC)
                      (HITEC-20170406)},
      pid          = {G:(DE-HGF)POF3-113 / G:(DE-Juel1)HITEC-20170406},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/826737},
}