铟锡合金真空蒸馏分离的研究

研究了真空蒸馏法分离铟锡合金,回收金属铟与锡的新工艺。从理论上分析了铟与锡分离的可能性和规律性,并进行工业化试验。工业化试验的结果表明,控制蒸馏温度1050℃,真空度3 Pa时,铟锡合金中的铟与锡能在较大程度上分离开,得到含铟量大于95%的粗铟,粗铟中的含锡量降至1%以下。铟的直收率达到92%,物料的总回收率达到99%。该方法是铟锡分离中流程短、无污染、低能耗的新工艺、新技术。     

铟锡氧化物陶瓷靶材热等静压致密化研究

用化学共常常法制备了铟锡氧化物（ＩＴＯ）复合粉末。粉末经冷等静压成型后进行热等静压致密化。热等静压时采用碳钢作包套,采用铜箔作隔层,实验研究了热等静压工艺参数－保温温度、保压压力和保温时间对ＩＴＯ陶瓷靶材致密化的影响。实验结果表明：靶材的相对密度在大约１０００℃处有一峰值;相对密度随压力增加而增加;当保温温度较低时,适当处长保温时间有利于提高密度;当保温温度较高时,延长保温时间反而使密度降低,分析     

高岭土煅烧活化过程研究

利用热重-差热、X射线衍射、红外光谱、扫描电子显微镜、拉曼光谱等测试手段,对高岭土煅烧活化过程进行研究,得到高岭土煅烧活化的温度范围,分析高岭土样品煅烧前后官能团的变化,并对其制备的地聚物进行抗压强度以及微观形貌对比。结果表明,高岭土的最佳活化条件为600℃下煅烧6 h,制备的地聚物水化浆体结构致密,水化产物呈层状堆积,7 d抗压强度达到62.7 MPa。     

真空蒸馏铟锡合金回收金属铟的研究

采用真空电阻炉对铟锡合金进行了实验研究。首先通过实验确定了较好的蒸馏时间和蒸馏温度范围。最后根据化验结果确定了对生产具有指导意义的实验条件,即对金属铟质量分数为90%的铟锡合金进行真空蒸馏时,采取的对生产具有指导意义的工艺条件为蒸馏温度1250℃,蒸馏时间60 min;蒸馏温度1300℃,蒸馏时间40 min;所得的金属铟的含铟量大于99%。     

铟锡氧化物陶瓷靶的制备

研究了铟锡氧化物(ITO)粉末退火后的组织和结构,比较了不同状态的粉末和制备工艺对ITO靶材的影响.结果表明,纳米ITO粉末在800℃以下具有体心立方In2O3结构,1100℃退火后由In2O3和SnO2两相组成;ITO粉末经过喷雾造粒后,形成了实心球形颗粒并具有合理的颗粒级配,通过气氛烧结可以制备出高密度优良的ITO...     

微波晶化法合成柱撑纳米层状双氢氧化物及其对PP阻燃性能的研究

采用低饱和态共沉淀,辅助微波手段快速合成了纳米ZnAl-C6H5SO3 LDHs,其粒径为20～100nm,分散性较好、颗粒团聚少.将其应用于聚丙烯(PP)中,详细研究其对PP阻燃性能及抑烟性能的影响.经氧指数(LOI)、扫描电镜(SEM)和锥形量热仪(CONE)等研究表明,改性后的LDHs在PP材料中分散良好,在将PP氧指数有效提高到28的同时降低了材料的热释放速率,有效延缓和抑制了材料的烟释放速率.     

煅烧温度对二氧化钛纳米晶性能的影响

研究了不同煅烧温度下,锐钛矿相、混晶和金红石相二氧化钛纳米晶的 粒径、比表面积和吸收光谱的变化。经相同的温度煅烧后,金红石相二氧化钛纳米晶的生长速率和比表面积下降速率均大大高于锐钛矿相,表明高温反应或煅烧难以获得金红石相纳米晶,真空热处理的金红石相二氧化钛纳米晶可以保持较高的比表面积和较小的粒径,但易导致非化学配比、晶格缺陷并降低了粉体的性能。     

铟锡氧化物薄膜的生产现状与应用

介绍了铟锡氧化物（ＩＴＯ）薄膜的特征,主要生产工艺及其在汽车、宇航、建筑、电子、太阳能等领域的应用。并对该材料生产工艺及产品市场的发展前景进行了展望     

机械化学法合成羟基插层Mg/Fe型层状双氢氧化物

Mg/Fe型层状双氢氧化物(LDH)是一类可有效去除水中有害组分(特别是有害阴离子)的无机吸附材料.常用的共沉淀法在合成层状双氢氧化物过程中容易产生大量碱性废水,且合成产物通常结晶度较低.本文利用改进的机械化学合成法,选取MgO和无定形态的Fe(OH)3作为反应前驱物,成功制备出了羟基(-OH)插层的Mg/Fe型层状双...     

退火处理对铟锡氧化物粉末的影响

对两种不同比表面积(BET)的铟锡氧化物(ITO)纳米粉末进行退火处理,研究和比较了温度对两种粉末微观组织和结构的影响,并对这两种粉末烧结的靶材进行了比较。结果表明,在800～1500℃进行不同温度的退火处理后,在1200℃以上,两种比表面积的ITO粉末粒径增长显著,颗粒之间出现了相互合并和结合长大现象,而高BET粉末的粒径增加幅度比低BET粉末的更大;在1525℃烧结后,用高BET粉末烧成的靶材的晶粒和气孔尺寸更大,气孔数量也更多。     

Design of composite porous cermets synthesized by hydrothermal treatment of CrAl powder followed by calcination

The microstructure of the porous Cr–Al metal–oxide cermet was studied by means of XRD, SEM, EDX as well as IR and Raman spectroscopy. This cermet was synthesized by mechanical alloying of Cr–Al powders in an AGO-2 planetary ball mill followed by hydrothermal treatment in a special stainless steel die and calcination in air. As a result, a highly porous monolith comprised of metal-like particles randomly distributed in the oxide matrix (Cr₂O₃ and Al₂O₃) was formed. Two types of the composite cores were found in cermets. The first one consisted of chromium phase containing nanoparticles sized from 50 to 140 nm and Al-enriched phase at the interfaces. The second one consisted of new chromium oxide phases with hexagonal Cr₂N-like and fcc CrN-like structures probably with Cr₂O and CrO stoichiometry. These new phases were stabilized within aggregates of the nanocomposite particles containing inclusions of alumina. The relations between different preparation stages and the cermet microstructure are discussed.     

Investigation of composite hydroxyapatite powder for plasma spraying bioceramic coatings

Powder synthesis on the basis of a matrix from nanocrystalline titanium dioxide with incorporated HA particles was developed. Using scanning and transmission electron microscopy (SEM and TEM), the shape, size, and relief of TiO₂-HA powder particles are investigated. When calculating for the powder particles using the SEM photos and TEM negative films on a picture analyzer, the granulometrical composition and the average maximum particle diameter (0.7 μm) are determined.     

Preparation of nickel-coated alumina composite powder by an aqueous-phase reduction process

A nickel coating on the surface of alumina particles, used as a reinforcement in metal-ceramic composite materials, substantially improves their wettability by molten metals. Nickel was deposited on alumina particles by reducing nickel ions from a solution under hydrogen pressure in the presence of ammonia as a complexing agent. It was found that the addition of Fe²⁺ ions and anthraquinone was necessary for forming an adequate nickel coating on the alumina surface. The optimum conditions were the [NH₃]/[Ni²⁺] ratio of 1.6, 2760 kPa hydrogen pressure, 175 °C, and an anthraquinone addition of 0.04 g l^–1.     

导电聚苯胺/纳米镍粉复合屏蔽材料的研究

制备了导电聚苯胺/纳米镍粉复合屏蔽材料.实验中把导电聚苯胺与镍粉以28的比例制成复合粉,然后再将复合粉与环氧树脂以37的比例混合,制成屏蔽涂料.检测结果显示,当聚苯胺电导率为102S/cm、镍粉颗粒尺寸为50～180nm、涂层厚度为0.45mm时,在30～1500MHz的频段范围可获得80～100dB的屏蔽效能.分析表明,大幅度提高吸收损耗,适当降低反射损耗可以减少二次电磁污染.这种屏蔽涂料不仅可用于电器机壳,而且也可用于电子元件、器件.     

直接碳化原位合成WC-Co复合粉的反应过程

以偏钨酸铵(AMT)、可溶性钴盐、有机碳源为原材料,采用喷雾转化、直接碳化原位合成法,成功制备出WC-Co复合粉末。利用XRD、SEM等分析方法对粉末样品物相组成、微观形貌、粒度分布进行了研究。研究表明,由于Co对W碳化的促进作用,在900℃时,W就被完全碳化为WC,远低于W正常被碳化完全的温度;W的碳化过程主要依靠钨粉颗粒表面与含碳气氛热解后沉积在钨颗粒表面上的碳元素的反应以及碳向钨粉颗粒内部的扩散来实现,属固-固反应;由于生成W2C的自由能比WC的更低,W很快先被碳化为W2C,然后再进一步碳化为WC;W/Co/C碳化反应体系沿WCo3,Co6W6C,W2C-Co,WC-Co步骤进行反应;随着温度的升高,反应体系可不经过前两步,而直接生成W2C-Co,再进一步碳化为WC-Co复合粉。     

Synthesis of Al2O3-WC composite powder by SHS process

Al₂O₃-WC composite powder was synthesized by self-propagating high-temperature synthesis using Al powder as a reducing agent. WC, W₂C and Al₂O₃ were concurrently formed in WO₃-Al-C system. It was found that the complete reaction was achieved with excessive addition of carbon and appropriate processing parameters such as degree of dilution, particle size of aluminum, pellet compaction pressure and carbon source. The final product which was leached by 50% 1 : 4 HNO₃ + HF diluted solution was consisted of Al₂O₃-55wt%WC having 2–3 m of mean particle size.     

Investigation of functional core-rim composite part production by inserted powder injection moulding

In this study, the use of Cu and Ni interlayers have been investigated for functional core-rim composite part production with WC-Co 9?wt-% feedstock/steel. For this purpose, different experiments have been performed and joining condition, shear strength and microstructure of the intermediate region have been examined. It has been found that AISI 4340 insert/WC-Co have been joined and 85.8?MPa shear strength achieved, but high speed steel insert has not joined. Moreover, it has been determined that better results are obtained with Ni interlayer. Under the same conditions, when the 40?µm Ni interlayer has been used between AISI 4340 core and WC-Co rim, shear strength has been increased approximately twice and has been 162.7?MPa.     

Preparation of high-purity and ultrafine WC-Co composite powder by a simple two-step process

In this study, high-purity and ultrafine WC-6%Co composite crystallites was synthesized by a simple two-step process consisting of the precursor-formation of the mixture of blue tungsten oxide (WO_2.9) and cobaltic oxide (Co₂O₃) and the following deep reduction and carburization with CH₄-H₂ mixed gases. The experimental results revealed that after the first carbothermic reduction stage at 1050 or 1150 °C, a mixture of W, WO₂ and Co₇W₆ was obtained, which was further carburized to the WC and Co phases by CH₄-H₂ mixed gases at 900 °C. With the increase of C/WO_2.9 molar ratio, the particle sizes of first-stage precursor and carbonized product were both decreased. The particle sizes of final products are mainly determined by C/WO_2.9 ratio and reaction temperature at the first stage. When the C/WO_2.9 ratio was in the range of 2.3–2.7, the high-purity WC-6%Co composite powder with the average particle sizes of 160–410 nm could be obtained.