煅烧工艺对α-Al2O3晶粒的影响

研究了煅烧温度 ,保温时间及矿化剂对α -Al2 O3 晶粒度的影响。试验表明 ,煅烧温度、硼类和氟类矿化剂都能使α -Al2 O3 晶粒度长大。煅烧时间在较低温度 ( 14 0 0℃ )下有利于α -Al2 O3 晶粒度生长 ,在 15 0 0℃以上对晶粒度基本没有影响。     

AlF3添加剂对氧化铝粉体微观结构的影响

在醇盐水解法制备a-Al2O3工艺过程中引入AlF3作为添加剂,通过XRD、SEM研究了AlF3加入量、水热条件、热处理温度对产物晶相及微观形貌的影响.研究结果表明:AlF3加入可使α-Al2O3相在800℃至900℃之间形成;相同水热温度下,随AlF3加入量增大,α-Al2O3的微观形貌是从不规则的板状结构向嵌入式六角板状结构发展;随水热温度升高,αa-Al2O3的微观形貌则由多面体结构向六角板状结构再到"蠕虫状"结构转变.     

NH4Cl对以碳酸铝铵为前驱体的氧化铝α相变的影响

利用NH4Cl其分解时释放气体的特点控制以碳酸铝铵为前驱体的氧化铝α相变过程中的团聚。采用DTA、XRD、SEM和粒度分析等手段研究了在升温过程中其对氧化铝α相变过程及产物的影响。结果表明，由于NH4Cl在分解时释放气体所产生的冲击作用，相变过程中团聚受到削弱，相变产物的粒径和晶粒尺寸都有所减小。但是氧化铝α相变温度并未有明显下降。     

国产氧化铝粉体的改性及其烧结性能研究

通过某国产氧化铝粉体的研麽和分散,得到颗粒粒度分布窄、颗粒大小均匀的氧化铝粉体;添加氧化镁为烧结助剂,分别进行无压烧结和真空烧结,研究了烧结温度对氧化铝陶瓷的相对密度、显微结构、抗弯强度和直线透过率的影响。在1500℃无压烧结样品品粒尺寸为2～3μm,抗弯强度达到545MPa;1850℃真空烧结样品的晶粒尺寸为20～30μm,直线透过率（600nm）达到32％。     

粉料粒度对氧化铝基陶瓷型芯材料性能的影响

研究了精密铸造叶片用氧化铝基复合陶瓷型芯刚玉粉料粒度对型芯物相、形貌、气孔率、抗蠕变性能、脱芯性能的影响。研究结果表明：粉料粒度对Al2O3基复合陶瓷型芯材料的气孔率、线收缩率和高温蠕变性能均有影响。根据实验数据，分析了几种粉料粒度对陶瓷型芯综合性能影响的机理，同时讨论了不同粉料粒度型芯的烧结机理。     

矿化剂对α-氧化铝原晶形貌的影响及在新产品开发中的应用

本文用电镜和激光粒度仪等手段，初步分析了矿化剂对α-氧化铝原晶大小和形貌的影响。指出α-氧化铝原粉是许多α-氧化铝原晶的聚合体，微粉制备的作用只是打散这种聚合体而不能破坏α-氧化铝原晶，因此α-氧化铝原晶的大小制约了其微粉加工的细度。深入研究矿化剂对α-氧化铝原晶形貌的影响，采用不同矿化剂控制α-氧化铝原晶的大小和形貌，是研究开发适应不同行业需要的高附加值α-氧化铝新产品的关键。     

纳米氧化铝粉体的绿色合成

以廉价的铝锭和异丙醇为起始原料,采用独特的分离提纯、回收再利用技术和溶胶凝胶工艺,合成高性能纳米氧化铝粉体,并利用TEM,XRD和石墨炉原子吸收法等对粉体的相组成、形貌和杂质含量进行分析研究.得出原料对粉体的形貌和组成没有影响,两种不同的Al源均制备出了粒径为10～20nm,球形γ-Al2O3粉体;而原料和蒸馏工艺对纳米氧化铝粉体的纯度有影响,随铝锭纯度的增加,所制备的纳米氧化铝所含的微量杂质含量明显下降.和一次蒸馏相比,二次蒸馏所得产物的主要微量杂质明显下降.利用重熔铝锭为原料,采用二次蒸馏工艺,制得了纯度高达99.99%的纳米氧化铝,且在制备过程中没有废液,废气排出,实现了高纯纳米氧化铝粉体的低成本、环保型生产.     

超声场中溶胶凝胶法制备纳米氧化铝粉体的研究

近年来，超声空化处理已被证明是一种制备纳米材料十分有效的技术，当将超声空化作用应用于溶胶凝胶法制备纳米粉体过程时，将为防止团聚体的生成创造一个独特的条件。本文以六次甲基四胺为沉淀剂，研究了超声场下溶胶凝胶法制备纳米Al2O3粉体的工艺，对产物进行了扫描电镜（SEM），X射线衍射（XRD）分析及粒度分析。实验结果表明，超声波的引入可显著提高粉体的性能。超声处理过的前驱体在1100℃煅烧2小时制得了团聚少，平均粒径在30nm左右的α-Al2O3粉体。超声波的辐射作用有利于纳米α—Al2O3粉体的制备，它的作用主要体现在防止胶粒之间的团聚和长大，及破碎团聚体的作用上。     

《化学品氧化铝》一书出版发行

由张占明为主编。宁云峰、江基旺为副主编仇振琢为特约编审的《化学品氧化铝》一书已于2004年5月出版发行。本文系统地介绍了化学品氧化铝的物理化学特性及制造工艺。着重介绍了不同特性化学品氢氧化铝、活性氧化铝的制取方法和应用领域。阐述了国内外学者对氢氧化铝变体的结构模型、水热转变及热分解行为等的最新观点，解释活性Al2O3的活性本质的论据；α-Al2O3用作高新技术材料的品种及制取方法；高品质低钠氧化铝的生产方法等。本书可供氧化铝生产、铝盐及铝酸盐精细化工、石油化工、催化剂及载体、刚玉陶瓷、耐火材料等行业的教学、科研和生产人员参考。本书售价每册50元（含邮费）。需要订阅的单位及个人请直接与《轻金属》编辑部联系。地址：辽宁省沈阳市和平北大街184号，邮编：110001，电话、传真：024—23261062。     

粉料粒度对氧化铝基陶瓷型芯材料性能的影响

研究了精密铸造叶片用氧化铝基复合陶瓷型芯刚玉粉料粒度对型芯物相、形貌、气孔率、抗蠕变性能、脱芯性能的影响.研究结果表明:粉料粒度对Al2O3基复合陶瓷型芯材料的气孔率、线收缩率和高温蠕变性能均有影响.根据实验数据,分析了几种粉料粒度对陶瓷型芯综合性能影响的机理,同时讨论了不同粉料粒度型芯的烧结机理.     

BN对IF钢连铸结晶器保护渣理化性能的影响

采用BN替代碳质材料,研究BN对IF钢连铸保护渣理化性能的影响,在此基础上设计开发出IF钢新型连铸保护渣.新型连铸保护渣在熔化特性、粘性特征、夹杂物吸收能力和结晶性能等方面与传统连铸保护渣十分接近.新型骨架粒子BN可以使连铸保护渣熔化温度、熔化速度、粘度和结晶温度减小、Al2O3吸收速率增大.采用新型连铸保护渣可以彻底解决IF钢的结晶器内增碳问题,不会发生IF钢增硼问题,而在非稳态浇注条件下可能发生增硼反应.     

The nature and impacts of fines in smelter-grade alumina

Fines in smelter-grade aluminas are recognized as a significant process problem in aluminum smelting. However, understanding the nature of this fine material and how it impacts the reduction process are less clearly understood. The combination of new analytical methods such as variable pressure scanning electron microscopy and very high field solid state nuclear magnetic resonance provide new insights into the phases present and their spatial distribution within aluminas, and suggest how such fine materials are generated, particularly during calcination in the alumina refinery.     

Characterizing the physical and chemical properties of aluminum dross

In this article, the results of an investigation of granular and compact aluminum drosses are reported. The bulk density of granular drosses was determined according to DIN 52110-B, while DIN 52102-RE-VA was applied to compact drosses. The salt contents of the drosses were measured by applying the leaching test DIN 38414-S4; the metal contents by the salt-melting process were measured on a laboratory scale. In addition to the density data, the particle-size analysis, the distribution of elements in the different fractions, composition, metal content of recovered alloys, and gas evolution were compiled in a dross identity card characterizing each dross and simplifying the preanalysis for recovery.     

改进氧化铝微粉生产工艺的几点想法

从目前多品种氧化铝－超细粉生产工艺现状的分析入手,指出生产中在粒度控制、生产效率等方面存在的缺陷,提出采用“振动粉磨－分级系统”,用以提高分级精度和生产效率,减少杂质引入量,进而大幅度提高产品质量,增加产品附加值,提高市场占有率。     

Effect of a gas discharge in the bulk of an electrolyte solution on its physical and chemical properties

The effect of a gas discharge at atmospheric pressure in dielectric tubes filled with an electrolyte solution on the acidity and electroconductivity of solutions of sulfuric acid, sodium hydroxide, and sodium sulfate at various concentrations has been studied. The dynamic current-voltage characteristics of the volume discharge have been obtained for a wide number of electrolytes. It is shown that such discharge action on the investigated solutions causes the growth of their pH and the decrease of their electroconductivity. The process under study is found to be periodic with the electrophysical parameters being dependent not only on the solution electroconductivity but also on its chemical composition.     

Diaphragm discharge influence on physical and chemical properties of electrolyte solutions

The results of the comparison of estimated (theoretical) and experimental values of electroconductivities in acid, alkali solutions, and tap water subsequent to the action of an underwater low voltage diaphragm discharge have been presented. The experiments showed disagreement between the experimental and estimated values, which suggests a change of the solutions structural characteristics.     

氧化铝含量对Ni-P化学复合镀层摩擦学性能的影响

采用化学镀技术制备了不同氧化铝含量的Ni-P复合镀层,并用球盘式磨损试验机测试了镀层的摩擦磨损性能。利用扫描电镜、光学显微镜和X射线衍射仪对镀层和对偶球的表面形貌、成分及微观结构进行了表征,分析了镀层的磨损机理。结果表明：镀层中氧化铝质量分数最高可达34.7%,但镀层磷含量显著降低,Ni-P合金基体为无定形结构;镀层的摩擦因数(约为0.49～0.58)高于Ni-P合金,且随着氧化铝含量的增加先降低后增加,镀层的维氏硬度从502上升至764,磨损率从1.2×10_-14 m₃/(Nm)单调下降至3.2×10_-15 m₃/(Nm),镀层的主要磨损机理由粘着磨损逐步转变为磨粒磨损。     

Effect of ZrO2 and MgO added in alumina on the physical and mechanical properties of spark plasma sintered nanocomposite

The aim of the present research work was to investigate the effect on the properties such as density, surface roughness, microhardness, fracture toughness and microstructure added with MgO and ZrO₂ in an alumina matrix. The magnesia-zirconia toughened alumina spark plasma sintered nanocomposite samples were developed successfully and found the suppressing grain growth and crack free microstructure. No damage was found due to thermal shock up to 1350 °C. The amount of ZrO₂was added with 5 vol%, 10 vol% and 15 vol%, while MgO added with 0.5 vol%, 1 vol% and 2 vol% in an aluminamatrix. Each composition was weighed and mixed together. After that, the powders were pressed under the rapid heating at the sintering temperature of 1250 °C, 1300 °C and 1350 °C and for 5 min holding time under pressure of 60 MPa simultaneously. The optimum properties were found with the compositions of 10 vol% of ZrO₂, 1 vol% of MgO in the Al₂O₃ matrix. It showed highest relative density (99.68%), minimum surface roughness (1.123 μm), highest microhardness (19.46 GPa) and minimum average grain size (0.595 μm). The highest fracture toughness was found to be 6.7 MPa.m^1/2 the added with 15 vol% of ZrO₂,1 vol% of MgO in the Al₂O₃ matrix for the holding time 5 min and a sintering temperature of 1300 °C. The X-ray diffraction analyses indicate the presence of major phases were ZrO₂, α-Al₂O₃, MgO, magnesia phase with minor peaks of the secondary phase MgAl₂O₄. This was found due to chemical reactions between the composite constituents present in the matrix during the sintering. Uniform microstructure was observed using a field emission scanning electron microscope and obtained the sub-micron level of grain size without any significant increases of grain size. The developed compositehas high hardness and toughness to make it more suitable for applications such as ballistic armor and thermal barrier coating.     

稀土Ce对Sn-Cu-Ni钎料物理性能和铺展性能的影响

研究了不同舍量的稀土Ce对Sn-Cu-Ni无铅钎料物理性能和铺展性能的影响.结果表明:添加微量的稀土Ce对Sn-Cu-Ni钎料合金的熔化温度和密度影响不大,而其电阻率有所上升.随着Ce含量的不断增加,钎料焊点表面的光亮度随之增加,钎料在铜基板上的铺展面积也逐渐增大,钎料润湿性有所改善,但是当w(Ce)超过0.05%时,钎料焊点表面光亮度呈现下降趋势,其铺展面积也在减小.