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The Al-TiO2-C refiners were prepared by the in-situ exothermic dispersion method using Al,TiO2 and C powders. The particle sizes of TiO2 were 30,60,90 nm and 200 nm, respectively. The effects of particle size of TiO2 on the refiner microstructure were studied. The refinement effect on industrial pure aluminum was evaluated. The XRD, SEM and EDS techniques were used to characterize the phase composition and the microstructure of Al-TiO2-C refiners. The results show that the Al-TiO2-C refiners compose of Al3Ti,TiC and Al2O3.The particle size of TiO2 directly affects the amount,distribution and morphology of the second phase. When the particle size of TiO2 is 30-90 nm,the amount of Al3Ti and TiC is large. However, the segregation phenomenon is obviously observed. The distribution of particles is not uniform. The Al3Ti is lath-like. When the particle size of TiO2 is 200 nm,the distribution of second phases is uniform and the amount is small. The Al3Ti is blocky. After adding the Al-TiO2-C refiner prepared by 30 nm TiO2, the nucleation temperature of α-Al increases from 659.4 ℃ to 661.8 ℃.Re-heating temperature is dropped from 1.2 ℃ to 0.3 ℃.The minimum average grain size is 633 μm. The refinement effect is the best in this condition.

The plasma-transferred arc technology has been observed to induce preferential grain orientation in multiple directions, leading to nonuniform grain growth within the alloy coating material. The addition of nano-oxides can act as heterogeneous nucleation sites, reducing the preferred orientation of grains. In this study, a low-speed mixing method was employed to coat highly dispersed CeO2 nanorods (CNRs) onto the surface of 14Cr2NiSiVMn alloy powder particles. The aim was to analyze the influence of dispersed CNRs on grain growth orientation in different directions and the refinement and heterogeneous nucleation effect of CNR additives. The addition of 0.5 wt.% CNRs resulted in the refinement of dendritic grains along both the perpendicular and parallel directions to the coating cladding direction, leading to the formation of more uniform equiaxed crystals. The combination of Ce with Si and V elements formed submicron particles, which promoted grain nucleation and reduced defects in the coating. Consequently, the mechanical performance of the sample significantly improved. In the deposition direction, there was a notable improvement in microhardness (20.4%), tensile strength (97.6%), and elongation (59.0%). In the perpendicular deposition direction, the tensile strength increased by 88.1%, and the elongation increased by 33.9%. Additionally, the weight loss due to wear decreased by 44.2%, and the relative wear resistance improved by 79.3%. [ABSTRACT FROM AUTHOR]

The Al-TiO2-C grain refiners with the mass fraction of 0.3% La2O3 were synthesized by the exothermic dispersion method using Al,TiO2,C, and La2O3 powders as raw materials, The refiners were fabricated by different compacting pressures, including 80, 85, 88, 90kN and 92kN respectively. Effect of Al-TiO2-C refiners prepared by different compacting pressures on refinement performance of ZL101 alloy was studied. The effects of compacting pressures on the phase morphology and microstructure of Al-TiO2-C refiners were investigated by using XRD, SEM and EDS analysis. The refinement capability of Al-TiO2-C refiners on ZL101 alloy was evaluated by using extracting characteristic values from thermal analysis cooling curves of ZL101 alloy, which comes from MATLAB software. The results show that the optimal compacting pressure is 90kN, Al3Ti exhibiting round block obviously increases and the size is uniformly distributed in the microstructure of refiners; moreover, the number of nucleation particles TiC as well as Al2O3 is increased. Al-TiO2-C has the best refinement performance on ZL101 alloy.

The Al-TiO2-C grain refiners were synthesized by the in-situ exothermic dispersion method by using TiO2,C and Al powders as raw materials. The microstructure of Al-TiO2-C refiners with different C/TiO2 was investigated by SEM, XRD and EDS. Grain refining test was carried out on industrial pure aluminum. The results show that Al-TiO2-C refiners are composed of Al3Ti,TiC and Al2O3. When the mole ratio of C to TiO2 is between 1:25 and 1:20, the amount of Al2O3 is moderate and its distribution is relatively dispersive. An excellent grain refining performance is obtained when adding 0.2% (mass fraction) Al-TiO2-C refiner with C/TiO2 is 1:20, the average grain size is about 142μm and there is no refining recession when holding 1h.

A cationic covalent organic polymer with bifunctional active site was synthesized, which was treated by N, N'-bis(5-bromomethylsalicylaldehyde)ethylenediamine (salen ligand) and tris(1H-imidazol-1-yl) triazine (TIT) in the presence of aluminum ethoxide. The bifunctional cationic covalent organic polymer was investigated by various characterization technologies including PXRD, FT-IR, XPS, TG, SEM, EDS, N2-adsorption and CO2-adsorption. In this polymer, aluminum acts as lewis acid site and bromine ion acts as nucleophile, cooperatively catalyzing the cycloaddition reaction of CO2 and epoxides. Due to its cooperative effect, a higher catalytic activity was found to exhibit 98.1% conversion of epichlorohydrin under optimized conditions (Initial pressure 1.0 MPa, 0.57 mol% catalyst of COP-Al, 90 °C, reaction time 18 h, in the absence of a co-catalyst). Notably, the heterogeneous catalyst still showed good activity and stability after five cycles. A salen-based cationic covalent organic polymers (COP-Al) was used as a bifunctional catalyst for the cycloaddition reaction of CO2 and epoxides with high activity under solvent-free and co-catalyst-free conditions. [ABSTRACT FROM AUTHOR]

A rhodium-catalyzed synthesis of indoloquinazolinone from a readily available hypervalent iodonium reagent and N-carboxamide indole was developed. The protocol features broad functional group tolerance, mild conditions, and excellent yields. The target products were obtained simply by filtration, without tedious column chromatography. Notably, the noble metal catalyst system can be recycled effectively at least ten times. The strategy may be amenable to industrial production. [ABSTRACT FROM AUTHOR]