Sen Liao

Nanocrystalline Zn0.5Ni0.5Fe2O4

Zn0.5Ni0.5Fe2(C2O4)3·6H2O was synthesized by solid-state reaction at low heat using ZnSO4·7H2O, NiSO4·6H2O, FeSO4·7H2O, and Na2C2O4 as raw materials. The spinel Zn0.5Ni0.5Fe2O4 was obtained via calcining Zn0.5Ni0.5Fe2(C2O4)3·6H2O above 773xa0K in air. The Zn0.5Ni0.5Fe2(C2O4)3·6H2O and its calcined products were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), Fourier transform FT-IR, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and vibrating sample magnetometer (VSM). The result showed that Zn0.5Ni0.5Fe2O4 obtained at 1073xa0K had a saturation magnetization of 86.7xa0emuxa0g−1. The thermal process of Zn0.5Ni0.5Fe2(C2O4)3·6H2O experienced three steps, which involved the dehydration of the six crystal water molecules at first, and then decomposition of Zn0.5Ni0.5Fe2(C2O4)3 into Zn0.5Ni0.5Fe2O4 in air, and at last crystallization of Zn0.5Ni0.5Fe2O4. Based on KAS equation, and OFW equation, the values of the activation energies associated with the thermal process of Zn0.5Ni0.5Fe2(C2O4)3·6H2O were determined to be 126.02xa0±xa023.93, and 259.76xa0±xa018.67xa0kJxa0mol−1 for the first, and second thermal process steps, respectively. Dehydration of the six waters of Zn0.5Ni0.5Fe2(C2O4)3·6H2O is multi-step reaction mechanisms. Decomposition of Zn0.5Ni0.5Fe2(C2O4)3 into Zn0.5Ni0.5Fe2O4 could be simple reaction mechanism, probable mechanism function integral form of thermal decomposition of Zn0.5Ni0.5Fe2(C2O4)3 is determined to be g(α)xa0=xa0[−ln(1xa0−xa0α)]4.

Nanocrystalline ZrO2 preparation and kinetics research of phase transition

The precursor of nanocrystalline ZrO2 was synthesized by solid-state reaction at low heat using ZrOCl2·8H2O, and Na2CO3·10H2O as raw materials. The nanocrystalline ZrO2 was obtained by calcining the precursor. The precursor and its calcined products were characterized using TG/DTA, FT-IR, XRD, and SEM. The results showed that the precursor dried at 353 K was a zirconyl carbonate compound. When the precursor was calcined at 673 K for 150 min, highly crystallization ZrO2 with tetragonal structure (space group P42/nmc (137)) was obtained with a crystallite size of 24 nm. However, when the precursor was calcined at 1023 K for 150 min, highly crystallization ZrO2 with monoclinic structure (space group P21/c(14)) was obtained with a crystallite size of 20 nm. The mechanism and kinetics of the thermal process of the precursor were studied using DTA and XRD techniques. Based on the Kissinger and Arrhenius equation, the values of the activation energies associated with the thermal process of the precursor were determined to be 26.80 and 566.73 kJ·mol−1 for the first and third steps, respectively. The mechanism of ZrO2 phase transition from tetragonal to monoclinic structure is the random nucleation and growth of nuclei reaction.

Standard Molar Formation Enthalpy of NH4Fe(HPO4)2

Ammonium-iron(III) bis(hydrogenphosphate) was synthesized via solid-state reaction at low temperature and characterized by X-ray diffraction, infrared spectroscopy and scanning electron microscope. Standard molar enthalpy of formation was determined by an isoperibol solution calorimeter at 298.15K. The results show that the obtained product is NH4Fe(HPO4)2 with shape of Lamellar particles. According to Hesss law, a new thermochemical cycle was designed, and the standard enthalpy of formation of the titled complex at 298.15K is: ΔfHmφ[(NH4)Fe(HPO4)2 (s), 298.15K] = −2641.52 ±0.06 kJ·mol−1.

Synthesis of Nano-Lamellar KZnPO4 via Solid-State Reaction and its Data Mining Technology

Potassium zinc phosphate was synthesized by solid-state reaction using K3PO4·3H2O and ZnSO4·7H2O as reagents. To investigate the influence of molar ratio, grinding time, holding temperature, holding time on yield and zinc content of the product, experimental project was designed by uniform design and data mining technology. Obtained product was characterized by X-ray diffraction, scanning electron microscope and energy disperses spectroscopy. The results show that the two mathematical models can be established by regression analysis according to yield and zinc content, which can be used to obtain the best technology conditions of solid-state reaction. Under the optimum reaction conditions: molar ratio of K3PO4·3H2O: ZnSO4·7H2O = 1.01, grinding time 31min, holding temperature 750°C, holding time 3.2 h, the prepared product is KZnPO4 with nano-lamellar structure, and the reaction average yield value is 84.33% and zinc content is 31.29%.

Nanocrystalline Zn 0.5 Ni 0.5 Fe 2 O 4

Zn0.5Ni0.5Fe2(C2O4)3·6H2O was synthesized by solid-state reaction at low heat using ZnSO4·7H2O, NiSO4·6H2O, FeSO4·7H2O, and Na2C2O4 as raw materials. The spinel Zn0.5Ni0.5Fe2O4 was obtained via calcining Zn0.5Ni0.5Fe2(C2O4)3·6H2O above 773xa0K in air. The Zn0.5Ni0.5Fe2(C2O4)3·6H2O and its calcined products were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), Fourier transform FT-IR, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and vibrating sample magnetometer (VSM). The result showed that Zn0.5Ni0.5Fe2O4 obtained at 1073xa0K had a saturation magnetization of 86.7xa0emuxa0g−1. The thermal process of Zn0.5Ni0.5Fe2(C2O4)3·6H2O experienced three steps, which involved the dehydration of the six crystal water molecules at first, and then decomposition of Zn0.5Ni0.5Fe2(C2O4)3 into Zn0.5Ni0.5Fe2O4 in air, and at last crystallization of Zn0.5Ni0.5Fe2O4. Based on KAS equation, and OFW equation, the values of the activation energies associated with the thermal process of Zn0.5Ni0.5Fe2(C2O4)3·6H2O were determined to be 126.02xa0±xa023.93, and 259.76xa0±xa018.67xa0kJxa0mol−1 for the first, and second thermal process steps, respectively. Dehydration of the six waters of Zn0.5Ni0.5Fe2(C2O4)3·6H2O is multi-step reaction mechanisms. Decomposition of Zn0.5Ni0.5Fe2(C2O4)3 into Zn0.5Ni0.5Fe2O4 could be simple reaction mechanism, probable mechanism function integral form of thermal decomposition of Zn0.5Ni0.5Fe2(C2O4)3 is determined to be g(α)xa0=xa0[−ln(1xa0−xa0α)]4.