振动球磨制备Fe-6.5 %Si硅钢微粉

采用振动球磨法制备Fe-6．5％Si（质量分数）硅钢微粉，试验中对硅钢粉末进行不同球料比、不同球磨时间、干法球磨和湿法球磨制备微粉试验。结果表明：随着球磨时间的延长，颗粒尺寸变细，球磨12h后，颗粒细化速度变慢；加大球料比及延长球磨时间可进一步细化粉末粒度，但对粉末的粒度分布无影响；湿磨比干磨制粉效率高，粒度分布多在小粒级范围内。     

Fe2O3粉末表面非均匀成核法包覆

为解决氧化铁红在高温下呈现不稳定性的问题, 采用非均匀成核法使Si（OH）4和Al（OH）3均匀包覆在氧化铁红粉末颗粒表面, 用X射线衍射仪、透射电镜、 Zeta电位测定仪对包覆前后的Fe2O3粉末颗粒进行分析. 结果表明, 通过非均匀成核法可以制备出被SiO2和Al2O3包覆的Fe2O3复合粒子, 其技术的关键是如何控制反应溶液pH值和涂层物质沉淀的反应浓度, 以保持被覆颗粒稳定的悬浮特性.     

氢氧化镧和氢氧化钕微粉的制备

采用化学共沉淀法制备La(OH)3和Nd(OH)3微粉,研究了反应物浓度、氨水浓度、滴定速度以及加入分散剂对制备La(OH)3微粉和Nd(OH)3微粉粒度的影响,初步确定了制备D50≤1μm的La(OH)3微粉和Nd(OH)3微粉的最佳工艺条件。     

高能球磨法制备超细Al2O3粉末

采用高能球磨法制备超细Al2O3粉末,研究了球磨时间、球磨转速及工艺控制剂等工艺参数对Al2O3粉末粒度和形貌的影响。结果表明:在一定范围内,延长球磨时间,提高球磨转速均能有效地减小颗粒尺寸;在球磨过程中加入工艺控制剂,能有效地防止粉末粘附在磨球和磨罐上,并改善粉末颗粒的均匀性。在本文试验条件下,加入工艺控制剂乙醇,球磨转速为400r/min,球磨时间为30h等条件下,获得Al2O3粉末的D50为0.82μm,Al2O3粉末粒径分布在0.12～6.37μm范围内。     

热分解对镍化合物粉末粒度与形貌的影响

对尿素均匀沉淀、碳酸铵沉淀和草酸盐沉淀所得镍的化合物粉末及其热处理样品,采用SEM、XRD、激光粒度分析仪和氮吸附仪进行表征。结果表明：不同沉淀体系形成的粉末粒度和形貌等各不相同,且在热分解过程中的变化行为也不同。较低温度下（如400℃）的热分解产物较好地继承了沉淀粉末的原有特征;温度过高时（如900℃）则易导致显著的烧结团聚。     

Al_2O_3掺杂钼合金粉末的形貌变化

采用水热合成法结合低温煅烧及两次还原工艺制备了Al2O3质量分数分别为0、0.25%、0.5%、0.75%、1.0%的钼合金粉末。通过SEM观察了混合钼合金粉末的形貌,采用XRD分析了钼合金粉末的相组成,研究了不同制备阶段Al2O3掺杂量对钼合金粉末的影响。结果表明:Al2O3掺杂量对钼合金粉末的均匀性、颗粒分布、粒径大小有一定影响,Al2O3掺杂量的增加对钼合金粉末的团聚有分散作用。经两次氢气还原,片状的MoO3颗粒完全被还原为球状的Mo颗粒,混合粉末主要由Mo和α-Al2O3相组成,不含其他相。α-Al2O3能细化还原后的Mo颗粒,且Al2O3掺杂量越大,Mo颗粒的细化效果越显著。     

低碳钢表面改性用耐磨无机涂层的研究

文章介绍了运用磷化技术和溶胶一凝胶技术,在AlCl3＋Al的水解体系中制备得到Al（OH）,凝胶,经烧成后在低碳钢表面形成活性Al2O3涂层。实验分析了磷化时间、涂覆溶胶中Al（On）,浓度以及涂层的厚度等对无机涂层与基体结合力的影响。同时运用X衍射分析与视频显微镜对基底表面包覆的Al2O3涂层的形成过程、形貌、相结构等进行表征和分析。实验结果表明通过磷化作用后的金属基底表面能转变成一种易于跟Al2O3涂层结合的磷酸盐薄膜,能有效地增强Al2O3溶胶与金属载体的附着力,使其表面形成均匀的致密氧化铝薄膜涂层。     

掺杂方式对Al2O3/Mo复合材料组织及性能的影响

分别采用固-固、液-固和液-液掺杂方式向钼粉中引入Al2O3,然后用粉末冶金法制备出掺杂钼粉,经压制、烧结制成Al2O3颗粒增强钼基复合材料.对掺杂钼粉及钼坯进行SEM形貌观察,并测定复合材料的密度和显微硬度.结果表明,液-液掺杂能够制备出粉末颗粒小、密度及硬度高的Al2O3/Mo复合材料,其掺杂Al2O3颗粒细小且分布较均匀.     

低温热处理以及高能球磨对制备超细氧化铝的影响

以Al2（SO4）3与（NH4）2CO3为原料，采用液相沉淀法，制备出前驱物NH4Al（OH）2CO3（碱式碳酸铝铵），利用低温热处理以及高能球磨对前驱物进行了处理，并煅烧得到α～Al2O3。运用XRD、振实密度、SEM等现代分析检测技术对样品进行表征。结果表明：采用低温热处理能改善Al2O3粉体的分散性，并能在一定程度上促进Al2O3的晶型转变；采用高能球磨能在很大程度上改善Al2O3粉体的分散性，并且能极大地促进Al2O3的晶型转变，制备出片状Al2O3粉末。经过低温热处理与高能球磨的前驱物，在1100℃煅烧2h，能得到无团聚、粒径为500nm左右的片状超细α-Al2O3粉末。     

用喷雾干燥法制备PSZ-3Y粉末颗粒的形貌研究

用激光衍射法和SEM（Scanning Electron Microscope)法研究了喷雾干燥法制备PSZ-3Y粉末的粒度分布和形貌特征，表明用传统法制备的PSZ-3Y虽然可以获得细颗粒粉末，但是团聚非常严重，分散性能和流动性都很差，而用喷雾干燥法制备的PSZ-3Y粉末和造粒可以获得粒度分布均匀，流动性和分散性好的不团聚的球状颗粒。粉末的形貌与其采用的制粉原料的组成形态和工艺关系不大，但从原粉中喷雾制粒获得粉末的颗粒表面较粗糙和有小裂纹，其分布性能比直接喷雾粉末颗粒性能好。     

Effect of scandia on tungsten oxide powder reduction process

Scandia doped tungsten powders were prepared by spray drying combined with two-step hydrogen reduction.The particle size of doped tungsten powder,powder morphology and doped tungsten matrix were characterized by scanning electron microscope,X-ray diffrac-tion and laser diffraction particle size analyzer,respectively.The reduction behavior of Sc2O3 doped tungsten oxide and the effect of Sc2O3 on the property of tungsten powder were studied by the temperature programmed reduction.The experimental results showed that the pre-cursor powders prepared by spray drying had spherical shape.The addition of Sc2O3 could decrease the reduction temperature of tungsten oxide.The scandia doped tungsten powder had sub-micrometer size in the range of 0.1 to1 μm and scandium distributed evenly in the powder.By using this kind powder,sub-microstructure cathode matrices with semispherical grains and homogenous distribution of scan-dium were obtained.     

Effect of scandia on tungsten oxide powder reduction process

Scandia doped tungsten powders were prepared by spray drying combined with two-step hydrogen reduction. The particle size of doped tungsten powder, powder morphology and doped tungsten matrix were characterized by scanning electron microscope, X-ray diffraction and laser diffraction particle size analyzer, respectively. The reduction behavior of Sc₂O₃ doped tungsten oxide and the effect of Sc₂O₃ on the property of tungsten powder were studied by the temperature programmed reduction. The experimental results showed that the precursor powders prepared by spray drying had spherical shape. The addition of Sc₂O₃ could decrease the reduction temperature of tungsten oxide. The scandia doped tungsten powder had sub-micrometer size in the range of 0.1 to1 μm and scandium distributed evenly in the powder. By using this kind powder, sub-microstructure cathode matrices with semispherical grains and homogenous distribution of scandium were obtained.     

机械热化学法制备的Mo-Cu复合粉末及其性能

钼酸铵热解氧化物与铜粉经过球磨混合后,在H2气氛下进行共还原,制得Mo-30Cu复合粉末,利用X射线衍射、SEM等测试分析手段对复合粉末进行表征,研究粉末的压制行为和烧结性能,并研究烧结温度对Mo-Cu合金的致密度、热导率和电导率的影响。结果表明:采用机械-热化学法可以制备出颗粒均匀的Mo-Cu复合粉末,该粉末具有良好的压制性;随烧结温度的升高,Mo-Cu合金的致密度、热导率和电导率提高,经1 280℃烧结后,合金的致密度可达99%以上,显微组织分布均匀,合金的热导率最高达到196.5(W.m-1.K-1),电导率达50.5 IACS。     

超细陶瓷粉末表面改性处理

采用分步沉淀法制备ZrO_2(Y_2O_3)超细陶瓷粉末。制备过程中利用有机大分子作处理剂进行粉末表面改性处理。使用先进压汞仪、TEM、SEM、XRD等检测技术对粉末密度、孔隙分布、烧结性以及形态、相组成等进行测定。结果表明,适量的处理剂有利于控制粉末团聚状态,改善其分散性、流动填充性,使粉末及粉末压坯孔隙分布变窄,孔径细小,粉末颗粒球形度好,粒径小而均匀,凹方相ZrO_2含量增高,粉末烧结性等也明显优于未经处理的粉末。     

Obtaining of a finely dispersed powder of gadolinium hydroxide

Finely dispersed powders of gadolinium hydroxide are obtained by chemical deposition (dispersing). The influence of various factors on the powder characteristics such as dispersity, morphology, and chemical composition is investigated. The dependence that the mentioned characteristics have on the character of the anion of the gadolinium salt, the concentration and acidity of its solution, and the concentration of the precipitant and pH of precipitation, is established. The optimal results are observed with the use of diluted chloride solutions of gadolinium and a 5–10 wt % precipitant in the form of the NH₃ solution.     

喷雾干燥-冷等静压-烧结法制备ITO靶材的工艺研究

以化学共沉淀法制备的ITO粉末为原料,采用喷雾干燥-冷等静压-烧结法制备了ITO靶材,通过扫描电子显微镜(SEM)观察粉末、素坏及烧结后ITO靶材的表面形貌和气孔分布,并就粉末不同粒度组成对靶材压制与烧结效果的影响进行了分析.实验结果表明:通过喷雾干燥-冷等静压-烧结工艺可制备出相对密度大于97%的ITO靶材,喷雾干燥...     

Use of certain binders to increase the strength of green compacts

The effect of additives of certain binders to produce an increase in the strength of compacts of copper and iron powders is experimentally investigated. The best results are obtained upon the addition of 5 mass% polyvinylacetate to the powder. Through the use of this binder it becomes possible to saw and drill powder compacts prior to sintering.     

扩散工艺对铜合金粉末物理性能的影响

本文通过不同扩散工艺制备了Cu-Zn-Fe合金粉末,并对粉末的物理性能进行了检测,结果表明颗粒结构和颗粒形貌是影响粉末松装密度、流速、粒度分布的主要因素,同时利用粉末烧结理论解释了扩散温度和扩散时间对粉末物理性能的影响规律.     

Application of mechanochemical activation in production of zircon ceramics

The processes of preliminarily treatment of powders of various zircon concentrates when obtaining zircon ceramics are investigated. Based on the results of Raman spectroscopy, it is shown that, even at an insignificant content of impurities in the zircon concentrate, samples of powders with a small specific surface are prone to decomposition in the course of smelting at t = 1600°C. Mechanochemical activation with additives of surfactant species yields an increase in the milling efficiency and sinterability of the powder. However, resistance to the thermal decomposition of the samples increases. Based on an activated powder without the addition of any sintering activators, almost single-phase zircon ceramics with a residual porosity of <10% and a temperature of thermal decomposition over 1600°C was obtained.