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Author

Changqing Liu

Other affiliations: University of Hull
Bio: Changqing Liu is an academic researcher from Loughborough University. The author has contributed to research in topics: Soldering & Intermetallic. The author has an hindex of 31, co-authored 250 publications receiving 4395 citations. Previous affiliations of Changqing Liu include University of Hull.


Papers
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Journal ArticleDOI
TL;DR: In this article, the equivalent circuits for electrochemical impedance spectroscopy (EIS) modelling of PVD coated steels in 0.5 N NaCl solution were established and the circuit parameters obtained are correlated with the dielectric characteristics, and microstructure of steels and PVD hard coatings.

442 citations

Journal ArticleDOI
TL;DR: In this article, a systematic study of PVD ceramic (TiN and CrN) coated mild steel and AISI 316L stainless steel was carried out using the Electrochemical impedance spectroscopy (EIS) technique as the coated systems were immersed in 0.5 N NaCl solution.

340 citations

Journal ArticleDOI
TL;DR: In this paper, electrochemical impedance spectroscopy (EIS) was employed to study the corrosion performance of two commercially available hard coatings (TiN and CrN) on mild steel substrate.

296 citations

Journal ArticleDOI
TL;DR: In this article, the corrosion resistance of mild steel coated with single layered and multi-layered TiN and CrN coatings has been studied, and it is shown that applying four layers of coating can enhance the corrosion performance of PVD TiN/CrN coated mild steel.
Abstract: The corrosion resistance of mild steel coated with single layered and multi-layered TiN and CrN coatings has been studied. The base material was coated with TiN and CrN by an electron-beam plasma-assisted physical vapour deposition (PAPVD) technique. ‘Single’ layers of TiN or CrN, which normally include an interlayer (approx. 100–200 nm) of Ti or Cr under the main TiN or CrN film, were prepared; four layers of TiN (or CrN) were produced by four sequential repetitions of the single-layer process. The microstructural features and corrosion performance were then compared. It is shown that applying four layers of coating can enhance the corrosion performance of PVD TiN and CrN coated mild steel. The corrosion resistance improvement is not only attributed to the increase in thickness, but also to the internal microstructure and phase composition. CrN coatings produced in this work proved to be particularly promising in terms of corrosion resistance, owing to their dense non-columnar structure which contained a mixture of three phases: Cr (b.c.c.), Cr2N (hexagonal) and CrN (f.c.c.). Mild corrosion reactions were observed in CrN coated steel during various electrochemical tests in aqueous salt solution, indicating that inter-phase corrosion had caused a redistribution of the current flow, so as to eliminate current concentration at small through-coating pinholes. This prevented rapid galvanic attack at the coating/substrate interface. More importantly however, in comparison with the columnar structure of TiN coatings, the dense structure with fine equiaxed crystallites made the CrN coatings less permeable to the corrosive medium.

207 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175°C to 250°C, where the kinetics obey a parabolic growth law until complete consumption of the Al pad.

188 citations


Cited by
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Journal ArticleDOI
06 Apr 2016
TL;DR: Marshall has unique expertise in leveraging new digital tools, 3D printing, and other advanced manufacturing technologies and applying them to propulsion systems design and other aerospace materials to meet NASA mission and industry needs.
Abstract: Propulsion system development requires new, more affordable manufacturing techniques and technologies in a constrained budget environment, while future in-space applications will require in-space manufacturing and assembly of parts and systems. Marshall is advancing cuttingedge commercial capabilities in additive and digital manufacturing and applying them to aerospace challenges. The Center is developing the standards by which new manufacturing processes and parts will be tested and qualified. Rapidly evolving digital tools, such as additive manufacturing, are the leading edge of a revolution in the design and manufacture of space systems that enables rapid prototyping and reduces production times. Marshall has unique expertise in leveraging new digital tools, 3D printing, and other advanced manufacturing technologies and applying them to propulsion systems design and other aerospace materials to meet NASA mission and industry needs. Marshall is helping establish the standards and qualifications “from art to part” for the use of these advanced techniques and the parts produced using them in aerospace or elsewhere in the U.S. industrial base.

481 citations

Journal ArticleDOI
TL;DR: In this article, the equivalent circuits for electrochemical impedance spectroscopy (EIS) modelling of PVD coated steels in 0.5 N NaCl solution were established and the circuit parameters obtained are correlated with the dielectric characteristics, and microstructure of steels and PVD hard coatings.

442 citations

Journal ArticleDOI
TL;DR: The passive film formed on the equiatomic CoCrFeMnNi high-entropy alloy (HEA) is enriched in Fe and Mn but depleted in Cr.

405 citations

Journal ArticleDOI
TL;DR: In this article, the main results found in recent literature about the corrosion performance of metallic bipolar plates are presented and compared to graphite-based ones, and the results show that metallic materials have better mechanical strength and better electrical conductivity than graphite materials.

399 citations