NiP-SiC （≈1 1wt% P） composite coatings were electroplated in a Brenner type plating bath. The coatings had amorphous nano-phase composite structure. Direct current and alternating current electrochemical tests were...NiP-SiC （≈1 1wt% P） composite coatings were electroplated in a Brenner type plating bath. The coatings had amorphous nano-phase composite structure. Direct current and alternating current electrochemical tests were carried out on such coatings in a 3.5wt% solution of NaCl to evaluate their corrosion resistance. The potentiodynamic polarization, electrochemical impedance spectroscopy （EIS） tests, and exposure experiments all show that the corrosion resistance of NiP-SiC coatings first increases and then decreases when the SiC content increases, but the corrosion resistance of NiP-SiC composite coating is better than that of amorphous NiP coatings.展开更多
A novel approach to produce an intermetallic composite coating was put forward.The microstructure,microhardness,and dry-sliding wear behavior of the composite coating were investigated using X-ray diffraction （XRD）,...A novel approach to produce an intermetallic composite coating was put forward.The microstructure,microhardness,and dry-sliding wear behavior of the composite coating were investigated using X-ray diffraction （XRD）,scanning electron microscopy （SEM）,energy dispersive spectrum （EDS） analysis,microhardness test,and ball-on-disc wear experiment.XRD results indicate that some new phases FeAl,Fe0.23Ni0.77Al,and Ni3Al exit in the composite coating with the Al2O3 addition.SEM results show that the coating is bonded with carbon steel metallurgically and exhibits typical rapid directional solidification structures.The Cr7C3 carbide and intermetallic compounds co-reinforced composite coating has a high average hardness and exhibits an excellent wear resistance under dry-sliding wear test compared with the Cr7C3 carbide-reinforced composite coating.The formation mechanism of the intermetallic compounds was also investigated.展开更多
Metastable phases formed during vitrification or devitrification open an avenue to study the intrinsic structural hierarchy in amorphous materials.The phase transformation sequence of Al89Ce11 amorphous ribbon was inv...Metastable phases formed during vitrification or devitrification open an avenue to study the intrinsic structural hierarchy in amorphous materials.The phase transformation sequence of Al89Ce11 amorphous ribbon was investigated using diff erential scanning calorimetry,in situ high energy X-ray diffraction(HEXRD)and ex situ high-resolution scanning transmission electron microscope.The results reveal the devitrification pathway following the reaction:amorphous→ε-Al_(60)Ce_(11)+fcc-Al→η-Al_(41)Ce_(5)+fcc-Al→Al_(11)Ce_(3)+fcc-Al.It has been found that bothε-Al_(60)Ce_(11)andη-Al_(41)Ce_(5)metastable phases have same Ce-centered 1-6-6-6-1 motif,suggesting that the structural motif can be inherited.Formation of metastable phase with large unit cell is related to the short-range orders developed during solidification.Structural heredity provides a new method to tailor the microstructure and properties of Al-based alloys based on genetic mechanism.展开更多
基金supported by the National High-Tech Research and Development Program of China(No.2002AA331080)the Scientific Research Key Program of Beijing Municipal Commission of Education (No.KZ200410028012)
文摘NiP-SiC （≈1 1wt% P） composite coatings were electroplated in a Brenner type plating bath. The coatings had amorphous nano-phase composite structure. Direct current and alternating current electrochemical tests were carried out on such coatings in a 3.5wt% solution of NaCl to evaluate their corrosion resistance. The potentiodynamic polarization, electrochemical impedance spectroscopy （EIS） tests, and exposure experiments all show that the corrosion resistance of NiP-SiC coatings first increases and then decreases when the SiC content increases, but the corrosion resistance of NiP-SiC composite coating is better than that of amorphous NiP coatings.
文摘A novel approach to produce an intermetallic composite coating was put forward.The microstructure,microhardness,and dry-sliding wear behavior of the composite coating were investigated using X-ray diffraction （XRD）,scanning electron microscopy （SEM）,energy dispersive spectrum （EDS） analysis,microhardness test,and ball-on-disc wear experiment.XRD results indicate that some new phases FeAl,Fe0.23Ni0.77Al,and Ni3Al exit in the composite coating with the Al2O3 addition.SEM results show that the coating is bonded with carbon steel metallurgically and exhibits typical rapid directional solidification structures.The Cr7C3 carbide and intermetallic compounds co-reinforced composite coating has a high average hardness and exhibits an excellent wear resistance under dry-sliding wear test compared with the Cr7C3 carbide-reinforced composite coating.The formation mechanism of the intermetallic compounds was also investigated.
基金Project supported by the National Natural Science Foundation of China(No.51478039)the Fundamental Research Funds for the Central Universities of China(Nos.FRF-TP-14-063A2 and FRF-TP-15-001C1)+2 种基金the Beijing Nova Program(No.Z151100000315053)the 111 Project(No.B12012)the Ningbo Science and Technology Project(No.2015C110020),China
基金the funding support from the National Key Research and Development program(No.2020YFC2200500)the support from“The Pearl River Talent Program”the US Department of Energy,Office of Science,Office of Basic Energy Sciences,under Contract No.DE-AC02-06CH11357。
文摘Metastable phases formed during vitrification or devitrification open an avenue to study the intrinsic structural hierarchy in amorphous materials.The phase transformation sequence of Al89Ce11 amorphous ribbon was investigated using diff erential scanning calorimetry,in situ high energy X-ray diffraction(HEXRD)and ex situ high-resolution scanning transmission electron microscope.The results reveal the devitrification pathway following the reaction:amorphous→ε-Al_(60)Ce_(11)+fcc-Al→η-Al_(41)Ce_(5)+fcc-Al→Al_(11)Ce_(3)+fcc-Al.It has been found that bothε-Al_(60)Ce_(11)andη-Al_(41)Ce_(5)metastable phases have same Ce-centered 1-6-6-6-1 motif,suggesting that the structural motif can be inherited.Formation of metastable phase with large unit cell is related to the short-range orders developed during solidification.Structural heredity provides a new method to tailor the microstructure and properties of Al-based alloys based on genetic mechanism.
