Baogang Guo

Bio: Baogang Guo is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Coating & Microstructure. The author has an hindex of 9, co-authored 10 publications receiving 666 citations.

Effects of NaAlO2 on structure and corrosion resistance of microarc oxidation coatings formed on AM60B magnesium alloy in phosphate–KOH electrolyte

Abstract: Microarc oxidation coatings on AM60B magnesium alloy were prepared in phosphate–KOH electrolytes with and without NaAlO 2 addition. The effect of NaAlO 2 on the characteristic of breakdown voltage in different concentrations of NaAlO 2 has been studied. The compositions, structure and morphologies of the oxide coatings formed in different concentrations of NaAlO 2 were determined by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion resistance of the oxide coatings was evaluated in 3.5 wt.% NaCl solution using potentiodynamic polarization tests. The results showed that the solution conductivity increased while the values of breakdown voltage decreased with the increase of concentration of NaAlO 2 . In both cases the coatings contained Mg, Al, O and P as well as a trace amount of Na and K, and were mainly composed of MgO and spinel MgAl 2 O 4 . The addition of NaAlO 2 into the base electrolyte resulted in the increase of spinel MgAl 2 O 4 in the oxide coating. Furthermore, the number and size of micropores on top of the surface decreased with the increasing concentration of NaAlO 2 , though the surface roughness increased with the NaAlO 2 addition. The coating formed in the electrolyte containing 8.0 g/L NaAlO 2 exhibited the highest corrosion resistance in NaCl solution.

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

Abstract: NiAl/hBN coating was successfully prepared on a Ni-based superalloy substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si3N4 from ambient to 1000 °C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings were observed using a scanning electron microscope. It was found that the laser cladding NiAl/hBN coating on the Ni-based superalloy substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 1000 °C. The friction and wear behavior of the laser cladding NiAl/hBN coating was strongly dependent on test temperatures. The coating had a small friction coefficient and wear rate as it slid against the ceramic counterpart at elevated temperatures up to 1000 °C. The wear mechanism was characterized by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 °C and mild adhesion wear and plastic deformation up to 400 °C and above.

Recent advances in designing superhydrophobic surfaces.

Abstract: The interest in superhydrophobic surfaces has grown exponentially over recent decades. Since the lotus leaf dual hierarchical structure was discovered, researchers have investigated the foundations of self-cleaning behavior. Generally, surface micro/nanostructuring combined with low surface energy of materials leads to extreme anti-wetting properties. The great number of papers on this subject attests the efforts of scientists in mimicking nature to generate superhydrophobicity. Besides the thirst for knowledge, scientists have been driven by the many possible industrial applications of superhydrophobic materials in several fields. Many methods and techniques have been developed to fabricate superhydrophobic surfaces, and the aim of this paper is to review the recent progresses in preparing manmade superhydrophobic surfaces.

A review on self-cleaning coatings

Abstract: This review article summarizes the key areas of self-cleaning coatings, primarily focusing on various materials that are widely used in recent research and also in commercial applications. The scope of this article orbits around hydrophobic and hydrophilic coatings, their working mechanism, fabrication techniques that enable the development of such coatings, various functions like Anti-icing, Electro-wetting, Surface switchability and the areas where selfcleaning technology can be implemented. Moreover, different characterization techniques and material testing feasibilities are also analyzed and discussed. Though several companies have commercialized a few products based on self-cleaning coating technology, much potential still remains in this field.