Search

Ceramic particles reinforced iron matrix composites attract considerable interest in the industrial engineering field due to the ceramic’s excellent fatigue and wear resistance. ZTA ceramic particle has been regarded as an ideal reinforcement phase. In this study, three-body abrasive wear behaviours and the mechanism of the ZTA/Fe composites and high chromium white cast iron Cr15 standard samples were investigated. The wear resistance of the ZTA/Fe composite was superior to the Cr15 standard sample under SiO2 abrasives. The extruded ZTA could protect the matrix surrounding ZTA ceramic particles. However, ZTA ceramic particles were cut together with the Cr15 matrix under SiC abrasives. The wear mechanism of the composites was a combination of the cutting and fatigue for SiC abrasives. This work was funded by the National Key Research and Development Programof China [grant number 2021YFB370 1204], National Natural Science Foundation of China [grant number 52175184], the Fundamental Research Funds for the Central Universities of China [grant number xzy012019010], the Key-Area Research andDevelopment Program of Guangdong Province [grant number 2019B010942001], the Natural Science Basic Research Program of Shaanxi [grant number 2021JM-011], Open Fund of National Joint Engineering Research Center for abrasion control and moulding of metal materials [grant number HKDNM201901], the China Postdoctoral Science Foundation [grant number 2021M702558], the Guangxi Innovation Driven Development Project [grant number GUIKEA A18242001]. Cong Li would like to acknowledge the support of the China Scholarship Council.

Atmospheric plasma spraying (APS) was taken to fabricate the NiCrAlY coating. The corrosion-wear properties of NiCrAlY coating was measured respectively under deionized water, artificial seawater, NaOH solution and HCl solution. Experimental results presented that the as-sprayed NiCrAlY coating consisted of Ni3Al, nickel-based solid solution, NiAl and Y2O3. In deionized water, the coating with the lowest corrosion current density (icorr) of 7.865 &times, 10&minus, 8 A/cm2 was hard to erode. Meanwhile, it presented a lower friction coefficient and the lowest wear rate. In HCl solution, NiCrAlY coating gave the highest corrosion current density (icorr) of 3.356 &times, 6 A/cm2 and a higher wear rate of 6.36 &times, 6 mm3/Nm. Meanwhile, the emergence of Al(OH)3 on the coating surface could reduce the direct contact between the counter ball and sample effectively, which was conducive to the lowest friction coefficient of 0.24.

NiAl matrix composite coatings were prepared using atmospheric plasma spraying (APS). The mechanical and tribocorrosion properties of the NiAl matrix composite coatings, incorporated with Cr2O3 and Mo, were investigated, and the synergistic effect between corrosion and wear was studied in detail. The microhardness of the composite coating improved from 195.1 to 362.2 HV through the addition of Cr2O3 and Mo. Meanwhile, the Cr2O3 and Mo phases were distributed uniformly in the composite coatings. The X-ray diffraction (XRD) peaks of Ni-based solid solution slightly shifted to the right after adding the Mo. This was probably due to the solid solution of Mo into the matrix. The NiAl&ndash, Cr2O3&ndash, Mo composite coating had the lowest corrosion current density, wear rate and friction coefficient of 9.487 &times, 10&minus, 6 A/cm2, 3.63 &times, 6 mm3/Nm, and 0.18, in all composite coatings as well as showing excellent tribocorrosion properties.

The microstructure of NiAl matrix high temperature lubricating composites containing BaO/TiO2 metallic oxides were investigated. The NiAl-BaO/TiO2 composites were fabricated by vacuum hot-pressing sintering. The diffraction peaks of NiAl slightly shifted to the left with the addition of BaO/TiO2 metallic oxide. The crystal plane distance of NiAl phase in the composite was bigger than that in NiAl material according to the Bragg equation. Meanwhile, the lattice distortion and dislocation occurred in the composite structure, which is probably due to the Ti element dissolve in the NiAl matrix during sintering. The cohesive energy and formation enthalpy of NiAl were improved with the incremental of Ti solution contents through density functional theory calculations, which was indicated that the Ti element could dissolve in the NiAl and was in good accordance with the results of XRD and TEM.

NiCrAlY and NiCrAlY-Mo coatings were fabricated by atmospheric plasma spraying (APS). The corrosion-wear performance of the coatings was investigated in artificial seawater and the synergistic mechanism between wear and corrosion were evaluated in detail. Results showed that the diffraction peaks of Ni3Al shifted to the right and the microhardness of the coating was improved from 329.8 HV to 342.5 HV with adding the Mo element. Meanwhile, the NiCrAlY-Mo coating had a lower friction coefficient, with a wear rate of 0.26 and 3.69 &times, 10&minus, 6 mm3/Nm, compared to the NiCrAlY coating with a wear rate of 0.37 and 4.67 &times, 6 mm3/Nm. The NiCrAlY coating had severe corrosion and the corrosion mainly occurred in grain boundary. Adding the Mo element, the Mo element was distributed in the grain boundary and the coating had a lower corrosion rate and visibly slighter corrosion. The NiCrAlY-Mo coating had excellent corrosion-wear properties in artificial seawater.