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Highlights: [•] Calculation results indicate that luminol can form an extended hydrogen-bonding network. [•] The simulated adsorption spectrums of the network model are in accordance with the experimental results. [•] The changes induced by hydrogen bonds are discussed. [ABSTRACT FROM AUTHOR]

In this paper, by regulating the A-site doped rare earth elements to achieve the transformation of entropy, the composition of (La 1/3 Nd 1/3 Eu 1/3) 2 Zr 2 O 7 (LNEZ) and (La 1/4 Nd 1/4 Eu 1/4 Y 1/4) 2 Zr 2 O 7 (LNEYZ) medium entropy ceramic system and (La 1/5 Nd 1/5 Eu 1/5 Y 1/5 Gd 1/5) 2 Zr 2 O 7 (LNEYGZ) high entropy ceramic system were designed and prepared. The results show that the thermal and mechanical properties of the ceramics are enhanced as the entropy value increases, and from this it is demonstrated that the crystal structure of the high-entropy LNEYGZ ceramics is the most disordered. Severe lattice distortions have the effect of hindering and enhancing the behavior of elemental expansion, phonon scattering, etc., and have the effect of enhancing the resistance of ceramics to sintering and heat insulation. Moreover, the small grain size enables the ceramic to have an enhanced ability to deflect cracks, and the fracture toughness of the ceramic is thus enhanced. [ABSTRACT FROM AUTHOR]

The phase instability of 6–8 wt% Y 2 O 3 partially stabilized ZrO 2 (YSZ) in high temperature and molten salt corrosion environment seriously limits its application above 1200 °C. In this study, the chemical co-precipitation method prepared Yb 2 O 3 and CeO 2 co-doping YSZ (YbCeYSZ) ceramic materials to improve the above issues. It was proposed to improve the defect of high-temperature phase instability of CeO 2 -doped YSZ materials by adding Yb 2 O 3. The phase stability, thermal insulation properties, and Na 2 SO 4 + V 2 O 5 molten salt corrosion behavior of YbCeYSZ ceramic materials were studied. The results showed that 2.5 mol% Yb 2 O 3 -4 mol% CeO 2 -YSZ material (2.5Yb4CeYSZ) had no monoclinic phase (m-ZrO 2) after holding at 1500 °C for 120 h due to forming more defect clusters in the system. Meanwhile, the 2.5Yb4CeYSZ had excellent thermal insulation performance and molten salt corrosion resistance, which was attributed to the strong phonon scattering in the 2.5Yb4CeYSZ material system and the low reactivity between the stabilizer and the corrosive salt. [ABSTRACT FROM AUTHOR]

• Heat treatment led to the growth of the grain size of the NiTi phase in the coatings. • The spinodal decomposition occurred in the NiTi 2 phase by cryogenic treatment. • The post-treatments affected the phase transformation characteristics of the coatings. • The coating after cryogenic treatment has the highest microhardness. YF 3 modification NiTi-Si coatings were prepared on Ti-6Al-4 V substrate by laser cladding. On this foundation, heat and cryogenic treatments were conducted respectively to explore the effect of after-treatment procedures. The consequence of post-treatment methods on the phase constituent, microstructure, mechanical property, and phase transition characteristics of post-treatment coatings was studied. The phase constituent of the three coatings was roughly the same, composed of NiTi and NiTi 2. The results show that heat treatment led to the coarsening of NiTi phase grain size and increased Si content in the NiTi 2 phase. In addition, due to the rapid cooling rate provided by cryogenic treatment, the spinodal decomposition of the Si element occurred in the NiTi 2 phase. Furthermore, the post-treatments also affected the phase transformation characteristics of the coatings. As the temperature of martensitic transformation is sensitive to the content of Ni element in the NiTi phase, the M s and M f points of the heat treatment coating were slightly higher. In contrast to the heat treatment, the M s and M f points of the cryogenic treatment coating decreased. The microhardness of the three coatings is as follows: cryogenic treatment > original coatings > heat treatment. The cryogenic treatment coating has the highest microhardness due to grain refinement and spinodal decomposition. In addition, the cryogenic treatment coating showed the best wear morphology. [ABSTRACT FROM AUTHOR]

In recent years, nickel–titanium (NiTi) coatings have shown excellent tribological performance due to their unique phase transition characteristics. However, in the laser cladding of NiTi coatings in a semi-open environment, there are still issues with nitrogen and oxygen impurities arising in the coatings due to their exposure to air. In this study, three rare earth (RE) compounds were used to modify NiTi coatings in a semi-open environment to obtain coatings without any impurities. The effect of different RE compounds (Y 2 O 3 , YF 3 and YCl 3) on phase composition, surface oxidation and mechanical properties were studied. NiTi, NiTi 2 and the impurity phase titanium nitride (TiN) were observed in the original and Y 2 O 3 modified coating. In addition, incompletely melted Y 2 O 3 exists in the Y 2 O 3 -modified coating. The coatings with YCl 3 and YF 3 were composed of NiTi and NiTi 2 phase and the TiN impurity phase was not observed in either coating. In addition, the oxidation phenomenon at the top of the coating gradually weakened in the original, Y 2 O 3 , YCl 3 and YF 3 -modified coatings. Furthermore, the R-phase was characterised in the YF 3 -modified coatings. The average microhardness values of the original, Y 2 O 3 , YCl 3 and YF 3 -modified coatings were 669.68 HV 0.3 , 755.1 HV 0.3 , 579.1 HV 0.3 and 390.47 HV 0.3 , respectively, of which the microhardness of the YF 3 -modified coating was the lowest. Although RE compounds did not significantly change the tribological properties, the Y 2 O 3 -modified coating exhibited the best tribological properties (∼0.886 mm, 2.6 mg). The results show that YF 3 can isolate pollutants from the air in the coating and protect the coating in a semi-open environment. • NiTi alloy coating was prepared by laser cladding in a semi-open environment. • The TiN impurity phase disappeared inside the coating after the addition of YF 3. • The coating with YF 3 addition has the lowest microhardness. • The YF 3 prevents the Ti element in coatings from being contaminated by N 2 in the air. [ABSTRACT FROM AUTHOR]

Abstract The fracture resistance of nanoscale MEMS films under high frequency impact seriously influences its service life. Nano impact test is a reliable technique to evaluate the fatigue fracture resistance of films by simulating the dynamic cyclic loading conditions. In this paper, a kind of Cu film was prepared by magnetron sputtering. The effects of loading parameters and indenter size on the fatigue damage behavior were studied for the Cu films during by nano impact test technique. The dislocation propagation and crack initiation during the nano impact process were also analyzed by molecular dynamics simulation. The results show that: Nano impact failure of Cu film can be divided into three stages and the main failure forms are cracks and delamination. The increase of the indenter radius leads to the increase of fatigue indentation size. The deformation range and damage accumulation degree of thin film material also increased correspondingly. With the increase of nano impact loading rate, the film material suffered more momentum from the indenter. The fatigue damage energy accumulation accelerates the damage. Highlights • Fatigue property of Cu Film was tested by nano-impact technology. • The nanometer impact fatigue process is simulated by molecular dynamics. • The damage mechanism of nanometer impact fatigue is analyzed. • Relationships between indenter size and loading rate and fatigue property are explained. [ABSTRACT FROM AUTHOR]

Abstract In order to obtain metallurgical shape memory alloy with a better quality, electro-magnetic stirring (EMS) technology is selected as an aiding method during plasma arc deposition (PAD) process. In this work, Ti 51 Ni 49 alloys were successfully produced by EMS-assisted PAD technology. Influence of EMS on the microstructure, phase transformation behavior, micro-hardness and wear resistance of PAD TiNi alloy have been systematically investigated. The PAD TiNi alloy is composed of TiNi coarse columnar dendrites with a certain number of Ti 2 Ni phases distributed in the inter-dendritic regions. Under the action of EMS, TiNi coarse columnar dendrites transform into fine non-dendrites or spheroid grains and the homogeneity of microstructures improves significantly. The implementation of EMS during PAD do not change the path of phase transformation, but improve the degree of phase transformations and reduce the transformation temperatures of PAD TiNi alloy. The EMS-PAD TiNi alloy possesses better dry wear resistance than the PAD TiNi alloy, which can be attributed to the higher degree of pseudo-elasticity of TiNi phases and strengthening of Ti 2 Ni phases. Highlights • Ti 51 Ni 49 shape memory alloys were successfully produced by electromagnetic stirring (EMS) - assisted plasma arc deposition (PAD) technology. • Under the action of EMS, TiNi coarse columnar dendrites transform into fine non-dendrites and its homogeneity improves significantly. • The EMS-PAD TiNi alloy possesses better dry wear resistance than the PAD TiNi alloy due to the higher degree of pseudo-elasticity and strengthening of Ti 2 Ni phases. [ABSTRACT FROM AUTHOR]

In this work, the CoNiAlBx coatings were successfully prepared on 38CrMoAl steel by laser cladding technology. The effects of B content addition on the microstructure, phase composition, microhardness, and tribological properties of the coatings were systematically analyzed. We found that CoNiAlB coatings were composed of β,γ,and FeB phase. TEM results shown that the orientation relationships between FeB phase and γ phase were [—112]FeB//[12]γ. With the addition of B, the microstructure changed from cellular morphology to dendritic morphology, then generated FeB phase, the transformation of microstructure led to the improvement of the coating: The microhardness improved from 380 Hv 0.3 to 790 Hv 0.3 , the friction coefficient reduced from 0.75 to 0.45, wear rate decreased from 3.59·10−14 m3 N−1 m−1 to 1.34·10−14 m3 N−1 m−1. The wear mechanism of CoNiAlB coatings was changed from only oxidation wear to only abrasive wear, exhibited excellent tribological property. [Display omitted] • FeB phase was appeared in CoNiAlB coatings due to the addition of B. • The crystallographic orientation relationships and d-spacing of two phases were analyzed. • The appearance of FeB phase improved the microhardness and friction property of the coating. • The microhardness was increased by ∼390 Hv0.3, wear rate decreased to 1/3 of the original. [ABSTRACT FROM AUTHOR]

The fracture behavior of high-profile high-entropy alloy coating was characterized by in-situ TEM tensile testing. The samples for in-situ TEM tensile testing were obtained by FIB technology. The results show that irrelevant to phase constitution, the Young's module, fracture strength and ultimate elongation are measured as ∼107 GPa, ∼2.70 GPa and ∼2.6%, respectively. Transcrystalline fracture and cleavage fracture with the cleavage plane of {112} are observed evidentially and the evolution of the dislocation motion in the material could be directly connected with the fracture behavior from the recorded movies obtained by a Gatan CCD camera. The engineering stress-strain curve is nearly linearity, however, a slight deviation away from linearity could be noted in the end of engineering stress-strain curve, which is attributed that the extra elastic deformation results in part of continued deformation. [ABSTRACT FROM AUTHOR]

The granulation of ammonium chloride (AC) fertilizer has been investigated in a laboratory scale based on the pan granulator at ambient temperature. Significant improvement of granulation efficiency of AC was achieved by using polyaluminium chloride (PAC) as solid binder and urea as granulation additive. Highly charged cations by PAC hydrolysis could reduce the electrostatic force of AC, resulting in efficient particle agglomeration. Analyzing the surface structure and characteristics of the PAC and AC granules revealed their interactions, which lead to the formation of aggregate nucleus. Furthermore, PAC contained a larger number of active groups, which served as bridges to form particle-polymer-particle complex, and facilitated the growth of particle. Meanwhile, urea and AC could react with each other to form stable inclusion complex which also had pronounced effect on the increase of granulation rate for AC. [ABSTRACT FROM AUTHOR]

Unanticipated a new and simple urea-ammonium chloride cocrystal synthesis method on industrial scale was found during attempts to produce a kind of granulated compound fertilizer. The aggregation of fertilizer powder can make the interaction among particles from loose to close, which generate mechanical pressure and in turn act as the driving force to benefit cocrystal growth. Additionally, the honeycomb-like channels constructed by other coexisting compound make the water evaporates more moderate, which can help the formation of supersaturated solution at suitable rate, further promote the growth of cocrystal. This approach possibly opens a new route toward the developing methodologies for cocrystal synthesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • CeO 2 nanoparticles modified GO composites were synthesized by hydrothermal method. • Electroless Ni-P coatings enhanced by modified GO were prepared on Mg-Li alloys. • The microstructure of coatings became uniform and dense after adding modified GO. • Adding modified GO was conducive to improving the wear resistance of coatings. • Modified GO significantly improved the corrosion resistance of coatings. A new strategy of CeO 2 nanoparticles integration with GO nanosheets (CeO 2 @GO composites) was adopted for reinforcing Ni-P coating on Mg-Li alloys. Besides, the effect of GO nanosheets and CeO 2 @GO composites as reinforced particles on the microstructure, corrosion resistance and wear resistance of Ni-P coating were investigated. CeO 2 nanoparticles with average size of 4.19 nm were uniformly synthesized on GO nanosheets by hydrothermal method. The cellular nodules of coatings were refined after adding GO nanosheets and CeO 2 @GO composites. Moreover, the compactness and flatness of CeO 2 @GO-Ni-P composite coating were better than that of GO-Ni-P composite coating. The average friction coefficient of CeO 2 @GO-Ni-P composite coating (0.331) was decreased by 17%, 35.5%, and 39.6% than that of GO-Ni-P composite coating, Ni-P coating and Mg-Li substrate, respectively. The addition of GO nanosheets and CeO 2 @GO composites both improved the corrosion resistance of coatings, while CeO 2 @GO-Ni-P composite coating has the best corrosion resistance. Compared with Mg-Li alloys, the self-corrosion potential of CeO 2 @GO-Ni-P composite coating (-0.35 ± 0.006 V) shifted to positive potential by 1.28 V, and the self-corrosion current density was reduced by two order of magnitude (1.41 ± 0.13 × 10-6 A⋅cm−2). This was mainly attributed to the synergistic effect of the CeO 2 nanoparticles on the GO nanosheets. [ABSTRACT FROM AUTHOR]

In this work, the effect of the dual-phase microstructure (FCC and Laves phases) of Ni 1.5 CrCoFe 0.5 Mo 0.1 Nb x (x = 0.55 hypoeutectic, 0.68 eutectic and 0.8 hypereutectic) high-entropy alloy coatings on their corrosion and tribo-corrosion behaviors were studied. In a 3.5 wt.% NaCl solution, the FCC phase behaved as anodic sites. With the increase of Nb content, the passive regions of the coatings increased slightly. Mott–Schottky analysis revealed that the improvement in the performance of the passive film is mainly attributed to the reduced point-defect density. The increased Laves phase changed the wear mechanism of the coatings from adhesive to abrasive wear. [Display omitted] • The effect of the dual-phase microstructure on the tribo-corrosion behaviors of the eutectic HEA coatings was studied. • The interaction between FCC and Laves phases in the coatings was revealed by EBSD. • Nb 0.68 and Nb 0.8 coatings exhibited nano-scale pitting sizes. • With the increase of Laves phase, the protective capability of the passive films on the coatings was improved. [ABSTRACT FROM AUTHOR]