Fe2O3／Al体系制备Al2O3粒子增强铝基复合材料

对Fe2O3与Al合金反应合成法制备Al2O3粒子增强铝基复合材料进行了研究.对所得复合材料进行组织观察,OM观察发现Fe以网状合金相形式存在;SEM观察显示原位颗粒分布均匀,颗粒细小,直径小于0.5 μm;TEM观测显示Al2O3颗粒边角圆滑、界面干净,与基体结合良好.对复合材料进行力学性能测试,硬度略有提高,室温抗拉强度略低,300℃时抗拉强度达到92.18 MPa,比基体提高了26%.     

Pseudo-semi-solid thixoforging of cup shell with Al/Al2O3

1 Introduction The composite has high strength and high hardness when some ductile metal is added into the ceramics, at the same time the fracture toughness can be improved availably[1?4]. We also know that the increase of toughness is because of the bri…     

氨化Si基Ga2O3／Al2O3制备GaN薄膜

研究了Ga2O3／Al2O3膜反应自组装制备GaN薄膜。首先利用磁控溅射法在硅衬底上制备Ga2O3／Al2O3膜，再将Ga2O3／Al2O3膜在高纯氨气气氛中氨化反应得到了GaN薄膜。用X射线衍射(XRD)，X光光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)和荧光光谱(PL)对样品进行结构、组分、形貌和发光特性的分析。测试结果表明：用此方法得到了六方纤锌矿结构的GaN晶体膜。     

氨化硅基Ga2O3／Al2O3制备GaN薄膜性质研究

研究了Ga2O3／Al2O3膜反应自组装制备GaN薄膜。首先利用磁控溅射法在硅衬底上制备Ga2O3／Al2O3膜，再将Ga2O3／Al2O3膜在高纯氨气气氛中氨化反应得到GaN薄膜。用傅里叶红外谱仪(FTIR)，X射线衍射(XRD)和扫描电镜(SEM)对试样进行结构、组分和形貌分析。通过分析薄膜各方面的性质，得出了用此方法制备氮化镓薄膜的Al2O3缓冲层最佳的厚度为15nm左右，最佳氨化条件是在900℃下氨化15min。     

原位生成Al2O3、TiB2和Al3Ti/Al复合材料的热循环行为

本文研究了Al-TiO2-B系原位生成Al2O3、TiB2和Al3Ti/Al颗粒增强铝基复合材料的热循环行为，研究结果表明了纯铝及B／TiO2摩尔比分别为0、1和2的颗粒增强铝基复合材料的热循环行为具有以下结果，纯铝和复合材料热循环后均产生了残余应变和滞后环；Al-TiO2-B系列复合材料热循环应变的各项指标均比纯铝基体大大降低，且具有较小的内耗功和较好的热稳定性，可以预测其具有较高的热疲劳寿命，热循环曲线能很好的评估复合材料在温度循环变化的环境中工作时的热稳定性和热疲劳。     

Oxidation Performance of Fe-Al／WC Composite Coatings Produced by High Velocity Arc Sprayed at 650℃

The Fe-Al/WC intermetallic composite coatings have been prepared by high velocity arc spraying(HVAS) technology on 20G steel and the oxidation performance of Fe-Al/WC composite coatings has been studied by means of thermogrativmetic analyzer. The results demonstrate that the kinetics curve of oxidation approximately follows the logarithmic law. The composition of the oxidized coating surface mainly is composed of Al2O3, Fe2O3, Fe3O4 and FeO which distribute unevenly. The protective Al2O3 film firstly forms and preserves the coatings from further oxidation.     

Al2O3对电沉积Ni-Co／AlO3复合镀层性能的影响

应用直流复合电沉积技术制备Ni—Co／Al2O3复合镀层，并研究了Al2O3对电沉积Ni—Co／Al2O3复合镀层性能的影响。结果表明：在本试验范围内，镀层的硬度和耐磨性随着Al2O3含量的增加而提高。     

Sintering densification and properties of Al2O3／PSZ （3Y） ceramic composites

1　INTRODUCTIONAl2 O3ceramicsisoneofthewide spreadingma terialsbecauseitholdsgoodfeaturessuchasresistancetohightemperature ,oxidation ,corrosionandabra sion .However ,thebrittlenatureofAl2 O3ceramicshaspromptedustoexploreavarietyofapproachestoenhanceitsfracturetoughness .SinceGarvieetal[1]advancedatheoryin 1975 ,thatistoimprovethefracturetoughnessandflexuralstrengthofZrO2 ce ramicswithmartensitictransformation ,ZrO2 hasbeenreceivingconsiderableattention .AddingMgO ,CaO ,Y2 O3andCeO2…     

The Microstructure and Mechanical Behavior Evaluation of Ce-TZP／Al2O3 Nanocomposites

Ce-TZP/Al2O3 nanocomposites were prepared from mixture of self-made Ce-TZP nanometer powder and commercial Al2O3 powder by hot-pressing method. Influences of nanometer ZrO2 particles on the mechanical properties and microstructure of Ce-TZP/Al2O3 ceramics were investigated. Meanwhile, t→m transformation toughening mechanism was investigated by x-ray diffractometry (XRD) method, and deflection of samples under applied stress were recorded too. The results show that when the percentage of ZrO2 was 20%, the mechanical properties and microstructures of materials were preferential. Additionally, TEM observation show that dislocation structures form both in the Al2O3 grain and on the Al2O3 grain boundary.     

自蔓延高温合成TiB2／Al2O3复合材料的力学性能

以普通商用TiO2为原料，与铝粉、碳化硼进行自蔓延（SHS）高温合成TiB2／Al2O3复合材料，通过差热和X射线衍射分析，确定了TiO2、Al及B4C的反应机制，得到了生成TiB2／Al2O3复合粉体的最佳工艺条件。测定了TiB2／Al2O3复合粉体相关的力学性能，得到材料的抗压强度为87．2MPa，抗弯曲强度为104．3MPa。SEM观察发现生成相中存在大量的气相或气孔，生成物微观区域不太均匀，材料的断裂形式主要为脆性断裂，生成物的颗粒尺寸为亚微米级。     

铝热还原法合成TiN／刚玉复合陶瓷的研究

以金属铝粉和钛白粉为原料，在流动氮气和匣钵埋碳保护气氛下采用铝热还原氮化法制备了TiN／刚玉复合陶瓷。采用XRD-SEM和TEM等分析手段，研究了铝热还原氮化法制备TiN／刚玉复合陶瓷在不同气氛和温度下的物相组成、晶格常数、显微结构。研究结果表明：在流动氮气和埋碳气氛下铝热还原法均可以制备TiN／刚玉复合陶瓷；处理温度和气氛明显影响着铝热反应的程度及产物的形貌，在埋碳条件下处理后的产物中TiN含量、晶粒大小、晶格常数明显低于流动氮气氛下处理产物中上述各项值。热力学计算发现埋碳条件下铝除参与铝热还原反应外，还与碳粉床中氧发生反应，导致参与铝热反应的金属铝不足，造成产物中有剩余的金红石存在。     

以白云石和菱镁石的混合物为原料真空铝热还原法炼镁的机理(英文)

利用SEM和EDS研究真空铝热还原煅白和煅烧菱镁石的混合物炼镁的反应机理。结果表明,根据在温度T时,t时间的还原率ηt与此温度下实验最终获得的还原率ηf的比,将还原过程分为三个阶段:0≤ηt/ηf≤0.43±0.06、0.43±0.06≤ηt/ηf≤0.9±0.02、0.9±0.02≤ηt/ηf<1。第一阶段为铝分别与煅烧菱镁石和煅白反应,主要产物为12CaO·7Al2O3和MgO·Al2O3,还原速率受化学反应的控制;Ca2+伴随熔融铝的扩散和化学反应速度决定了第二阶段的还原速率,CA相是此阶段的主要产物;CA2相在第三阶段产生,反应速率受Ca2+扩散控制。     

以白云石和菱镁石的混合物为原料真空铝热还原法炼镁过程的动力学（英文）

研究真空铝热还原煅烧白云石和煅烧菱镁石的混合物炼镁过程的动力学,提出一种满足真空铝热过程的等温还原方法。实验在4 Pa的真空下进行。实验结果表明:还原率随着温度、制团压力和铝粉添加量的提高而增加。对不同还原时间的还原渣进行XRD分析,结果表明,还原过程能够粗略地分为3个阶段:MgAl2O4和Ca12Al14O33的形成阶段;CaAl2O4的生成阶段;CaAl4O7的形成阶段。根据动力学模型将获得的实验数据分为3部分,这3部分的活化能分别为98.2、133.0和223.3 kJ/mol。     

Pt催化作用下无氢碳化制备纳米WC粉及其烧结性能研究

针对无氢碳化中反应速率缓慢、颗粒长大的问题,在无氢碳化过程中添加少量Pt作为催化剂,制备纳米WC粉。采用热压烧结对WC粉进行烧结得到无粘结相硬质合金。研究了Pt添加对WC粉的形貌和烧结性能的影响,以及Pt和烧结温度对烧结样品的致密化,组织和力学性能的影响。结果表明,少量的Pt可显著降低无氢碳化温度,制备的WC粉粒径细小且均匀。随着烧结温度升高,无粘结相硬质合金的致密度增加,晶粒尺寸增大,硬度与断裂韧性增加,但烧结温度过高,出现异常长大晶粒和W₂C,导致无粘结相硬质合金的断裂韧性严重下降。最佳烧结工艺为,烧结温度1700 ℃,保温60 min,压力40 MPa,所得无粘结相硬质合金致密度达到98.8%,平均晶粒尺寸为263.6 nm,维氏硬度和断裂韧性分别为2887 kg.mm^_-2和7.1 MPa.mm^_1/2。     

铝酸钠溶液碳酸化分解产品中的Na2O

对高浓度铝酸钠溶液碳酸化分解过程中Na2 O的析出行为和产品中Na2 O的存在形式进行了实验研究。结果表明 :溶液中NaAl(OH) 4的过饱和度是高浓度铝酸钠溶液碳酸化分解的主要动力 ,并直接影响产品中吸附碱和晶间碱含量水平 ;提高分解温度、添加晶种或钾碱均可以明显降低产品的Na2 O含量 ;表面吸附和晶间夹杂存在的可洗碱一般占氢氧化铝产品中Na2 O含量的 2 0 %～ 30 %,而晶格碱和含碱化合物杂质等不可洗碱是产品中Na2 O的主要存在形式。     

铝热还原酸溶性钛渣制备TiAl基多元合金

对含高钛的酸溶性钛渣进行铝热还原制备钛铝基多元合金。为了控制并了解合金的制备,讨论了铝和氧化钙的添加和温度的影响。通过考虑材料的配比计算,可以成功地使合金与渣合金分离。大多数还原元素的回收率表现为高值,在所有实验条件下均为95%。铝的添加主要影响合金的成分,而氧化钙的添加则通过改变渣系成分来影响渣金分离。此外,系统的温度可以提高大部分还原元素的回收率和分配比。     

Microwave permittivity of SiC-Al2O3 composite powder prepared by sol-gel and carbothermal reduction

SiC-Al2O3 composite powder was prepared by sol-gel and carbothermal reduction method. The powder synthesized was characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM） to confirm the phase formation, and the thermodynamic analysis was performed systematically. Moreover, the variation of its microwave permittivity with different atomic ratio of Al/Si was investigated in the frequency range of 8.2-12.4 GHz. The results show that, the powder obtained consists of spherical particles of 300-400 nm in diameter, which are composed of SiC and Al2O3 microcrystal with the grain size of approximately 45 nm. The results of XRD accord with those of the thermodynamic analysis. It is impossible for Al atoms to dissolve in the lattice of SiC during the carbothermal reduction process. Along with the increase of atomic ratio of Al/Si in the xerogel, the amount of Al2O3 in the powder synthesized increases, which reduces both ε＇, the real part of complex permittivity, and tg δ（ε＂/ε＇）, the dissipation factor, where ε＂ is the imaginary part of complex permittivity.     

铝热还原工艺条件对Al-Ti-Ce中间合金物相结构和合金元素浓度的影响

在Na3AlF6-NaCl-KCl氟氯混合电解质体系中,通过铝热还原法以TiO2和CeO2为Ti源和Ce源,制备Al-Ti-Ce中间合金。研究反应时间、反应温度、电解质构成（Na3AlF6质量百分含量）、K2TiF6添加量四种工艺条件对Al-Ti-Ce中间合金物相结构和合金元素浓度的影响。实验结果表明,在所有实验工艺参数范围内,制备的Al-Ti-Ce中间合金均由ɑ-Al、Al3Ti和Ti2Al20Ce三相构成。制备的最佳单因素工艺参数为：反应时间90 min,反应温度850℃,Na3AlF6质量百分含量40 %、K2TiF6添加量20 mol%。热力学分析结果从理论上进一步证明了在实验条件下几种主要化学反应的可行性。     

Synthesis of ZrO2-SiC composite powder and effect of its addition on properties of Al2O3-C refractories

ZrO2-SiC composite powder was synthesized by carbothermal reduction of zircon in argon atmosphere, and it was used as the additive to prepare Al2O3-C refractories. The effects of heating temperature on the synthesis process and the addition of the synthesized composite powder on the properties of the Al2O3-C refractories were investigated. The results show that the synthesized composite powder can be easily obtained by heating the mixture of zircon and carbon black at 1 873 K for 4 h in argon atmosphere, and the relative contents of ZrO2 and SiC in sample reach about 83.7% and 16.3%, respectively. The bulk density, crushing strength and thermal shock resistance of the Al2O3-C refractories can be improved obviously by the addition of the synthesized ZrO2-SiC composite powder.