Design of experiment of a novel cermet coating sprayed with the HVAF technology
Khanlari, Khashayar (2015)
2015
Master's Degree Programme in Materials Science
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2015-04-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201503251169
https://urn.fi/URN:NBN:fi:tty-201503251169
Tiivistelmä
Coating as a cover applied on the surface of the substrate can have different functional and engineering applications and purposes. There are so many different techniques for making coatings including thermal spraying, laser cladding, physical vapor deposition, chemical vapor deposition and etc. Each of these coating techniques is suitable for special kind of materials to be coated and each has some advantages and disadvantages.
Thermal sprayed coatings obtained by hard materials such as WC-Co, NiCr-Cr3C2, Ni-based and Cobalt-based powders are considered to be the best coatings to be deposited on big components that are involved in severe wear applications. This is duo to the combined effect of high thickness achievable by thermal spraying process and intrinsic mechanical behavior of these materials. Despite these mentioned properties, thermal sprayed coatings obtained by these materials have some drawbacks such as over fusion occurring at high process temperature and high cost of powder processing.
Iron-based cermet powder (70 (Fe,Cr)C / 30 FeNiCrSi) is designed with the aim of obtaining iron-based powders with the ability of competition and also solving the drawbacks of conventional powders. These thermal sprayed Fe-based coatings have been less investigated compared to WC-Co or Cr3C2-NiCr or Ni- and Co-based coatings.
Microstructure, micro hardness, roughness, open cell corrosion, wear and X-ray diffraction test were done on the coatings. Results show that despite using different processing factors; almost all coatings are dense and compact. In addition, coatings exhibit high hardness (around 700HV) which is comparable with hardness of conventional coatings. Furthermore, wear rate of the coatings were drastically lower than the substrate without any deposited coating.
In this work, Design of Experiment (DoE) as a useful technique is used for gaining more increased knowledge of the processing factors and optimizing these factors to achieve the best possible desired performance of HVAF thermal sprayed coatings obtained by this iron-based cermet. It is important to note that not all the factors affected the performance in the same manner. Some had strong impacts, some medium impact. Furthermore, interaction between the factors was also studied and analyzed in this report.
Thermal sprayed coatings obtained by hard materials such as WC-Co, NiCr-Cr3C2, Ni-based and Cobalt-based powders are considered to be the best coatings to be deposited on big components that are involved in severe wear applications. This is duo to the combined effect of high thickness achievable by thermal spraying process and intrinsic mechanical behavior of these materials. Despite these mentioned properties, thermal sprayed coatings obtained by these materials have some drawbacks such as over fusion occurring at high process temperature and high cost of powder processing.
Iron-based cermet powder (70 (Fe,Cr)C / 30 FeNiCrSi) is designed with the aim of obtaining iron-based powders with the ability of competition and also solving the drawbacks of conventional powders. These thermal sprayed Fe-based coatings have been less investigated compared to WC-Co or Cr3C2-NiCr or Ni- and Co-based coatings.
Microstructure, micro hardness, roughness, open cell corrosion, wear and X-ray diffraction test were done on the coatings. Results show that despite using different processing factors; almost all coatings are dense and compact. In addition, coatings exhibit high hardness (around 700HV) which is comparable with hardness of conventional coatings. Furthermore, wear rate of the coatings were drastically lower than the substrate without any deposited coating.
In this work, Design of Experiment (DoE) as a useful technique is used for gaining more increased knowledge of the processing factors and optimizing these factors to achieve the best possible desired performance of HVAF thermal sprayed coatings obtained by this iron-based cermet. It is important to note that not all the factors affected the performance in the same manner. Some had strong impacts, some medium impact. Furthermore, interaction between the factors was also studied and analyzed in this report.