采用高能球磨法制备了用于热浸镀锌的纳米C eO2/Zn复合粉末,并利用X射线衍射(X-ray d iffraction,XRD)、X射线光电子能谱(X-ray photoe lectron spectroscopy,XPS)、透射电镜(T ransm iss ion e lectron m i-croscopy,TEM)、扫描电镜(Sc...采用高能球磨法制备了用于热浸镀锌的纳米C eO2/Zn复合粉末,并利用X射线衍射(X-ray d iffraction,XRD)、X射线光电子能谱(X-ray photoe lectron spectroscopy,XPS)、透射电镜(T ransm iss ion e lectron m i-croscopy,TEM)、扫描电镜(Scann ing e lectron m icroscopy,SEM)以及能谱分析(X-ray energy d ispers ive spec-trum,EDS)等方法,对复合粉末的显微结构、表面成分、晶粒大小、微观形貌以及元素分布进行了研究。结果表明,随着球磨时间的延长,纳米C eO2硬团聚体逐渐解聚,Zn晶粒不断细化,形成层片状复合粉末;球磨120 m in后纳米C eO2粒子分散良好,呈理想的单个均匀弥散分布状态包覆在Zn颗粒上形成近似球形的复合粒子,其粒径分布均匀。展开更多
Nanocrystalline CeO2 powders (particle size ≈10-15 nm), doped with up to 20 at.-% of Mg,Ca or Y were prepared by chemical precipitation under hydrothermal conditions. The particle size and shape of the powders change...Nanocrystalline CeO2 powders (particle size ≈10-15 nm), doped with up to 20 at.-% of Mg,Ca or Y were prepared by chemical precipitation under hydrothermal conditions. The particle size and shape of the powders change slightly with the dopant concentrations. The the of the dopants on the sintering of the compacted powders was investigated during heating at a constant rate of 10℃/min. The elemental composition and the concentration of the dopant has significant efFect on the densification and grain growth. Compared to undoped CeO2, the dopants produce a shift in the densification curve to higher temperatures. For the same dopant concentration and under identical sintering conditions, the Ca doped samples reach nearly full density with the smallest grain size (≈50 nm), however, the Mg doped sample has the lowest density (≈95% of the theoretical) with the largest grain size (≈1 μm)展开更多
To satisfy practical requirements from industrial applications, an alternate route for synthesis compound ultrafine CeO2 powders by wet-solid-phase mechanochemical modification using industrial grade hydrated cerium c...To satisfy practical requirements from industrial applications, an alternate route for synthesis compound ultrafine CeO2 powders by wet-solid-phase mechanochemical modification using industrial grade hydrated cerium carbonate as raw material was proposed.The effect of modifier reaction percentage, reaction time, calcining temperature and modifier amount on particle size, density, suspensibility, and hardness of compound CeO2 powder was investigated.The phase evolutions of preparation process were characterized by XRD.SEM micrograph of the final product shows that compound CeO2 powders obtained are well-dispersed, spherically-shaped, uniformly-sized and submicron-sized particles.The method is readily available in raw material, low in cost, simple in process, and has great potential for industrialization.The compound CeO2 powders of different physical properties can be synthesized by controlling the above-mentioned influence factors in preparation process.展开更多
The crystallization in the three-component systems Rb2SO4-MSO4-H2O (M = Mg, Co, Ni, Cu, Zn) is studied by the method of isothermal decrease of supersaturation. It has been established that isostructural double compoun...The crystallization in the three-component systems Rb2SO4-MSO4-H2O (M = Mg, Co, Ni, Cu, Zn) is studied by the method of isothermal decrease of supersaturation. It has been established that isostructural double compounds, Rb2M(SO4)2·6H2O (M = Mg, Co, Ni, Cu, Zn), , crystallize from the ternary solutions within wide concentration ranges. The infrared spectra are discussed with respect to the normal vibrations of the sulfate ions and water molecules. The unit-cell group theoretical treatment of the double salts is presented. The extent of energetic distortions of guest ions (about 2 mol%) matrix-isolated in the respective selenates, (M' = K, Rb,;M" = Mg, Co, Ni, Cu, Zn), is commented.展开更多
文摘采用高能球磨法制备了用于热浸镀锌的纳米C eO2/Zn复合粉末,并利用X射线衍射(X-ray d iffraction,XRD)、X射线光电子能谱(X-ray photoe lectron spectroscopy,XPS)、透射电镜(T ransm iss ion e lectron m i-croscopy,TEM)、扫描电镜(Scann ing e lectron m icroscopy,SEM)以及能谱分析(X-ray energy d ispers ive spec-trum,EDS)等方法,对复合粉末的显微结构、表面成分、晶粒大小、微观形貌以及元素分布进行了研究。结果表明,随着球磨时间的延长,纳米C eO2硬团聚体逐渐解聚,Zn晶粒不断细化,形成层片状复合粉末;球磨120 m in后纳米C eO2粒子分散良好,呈理想的单个均匀弥散分布状态包覆在Zn颗粒上形成近似球形的复合粒子,其粒径分布均匀。
文摘Nanocrystalline CeO2 powders (particle size ≈10-15 nm), doped with up to 20 at.-% of Mg,Ca or Y were prepared by chemical precipitation under hydrothermal conditions. The particle size and shape of the powders change slightly with the dopant concentrations. The the of the dopants on the sintering of the compacted powders was investigated during heating at a constant rate of 10℃/min. The elemental composition and the concentration of the dopant has significant efFect on the densification and grain growth. Compared to undoped CeO2, the dopants produce a shift in the densification curve to higher temperatures. For the same dopant concentration and under identical sintering conditions, the Ca doped samples reach nearly full density with the smallest grain size (≈50 nm), however, the Mg doped sample has the lowest density (≈95% of the theoretical) with the largest grain size (≈1 μm)
基金Project supported by the National Natural Science Foundation of China (20163002)and the Jianxi Natural Science Foundation( 0220004 )
文摘To satisfy practical requirements from industrial applications, an alternate route for synthesis compound ultrafine CeO2 powders by wet-solid-phase mechanochemical modification using industrial grade hydrated cerium carbonate as raw material was proposed.The effect of modifier reaction percentage, reaction time, calcining temperature and modifier amount on particle size, density, suspensibility, and hardness of compound CeO2 powder was investigated.The phase evolutions of preparation process were characterized by XRD.SEM micrograph of the final product shows that compound CeO2 powders obtained are well-dispersed, spherically-shaped, uniformly-sized and submicron-sized particles.The method is readily available in raw material, low in cost, simple in process, and has great potential for industrialization.The compound CeO2 powders of different physical properties can be synthesized by controlling the above-mentioned influence factors in preparation process.
文摘The crystallization in the three-component systems Rb2SO4-MSO4-H2O (M = Mg, Co, Ni, Cu, Zn) is studied by the method of isothermal decrease of supersaturation. It has been established that isostructural double compounds, Rb2M(SO4)2·6H2O (M = Mg, Co, Ni, Cu, Zn), , crystallize from the ternary solutions within wide concentration ranges. The infrared spectra are discussed with respect to the normal vibrations of the sulfate ions and water molecules. The unit-cell group theoretical treatment of the double salts is presented. The extent of energetic distortions of guest ions (about 2 mol%) matrix-isolated in the respective selenates, (M' = K, Rb,;M" = Mg, Co, Ni, Cu, Zn), is commented.
