氯化铁催化合成苯甲酸异丙酯

探讨了氯化铁催化合成到异丙酯的反应条件及机理。     

Effect of processing parameters on microstructures and mechanical properties of rapidly solidified AlFeVSi hot-extruded product

1　INTRODUCTIONRapidlysolidifiedAlFeVSialloy ,developedus ing planarflowcastingbytheAllied SignalAlu minumCompanyofUSA ,isoneofthemostmatureheat resistantaluminumalloysatpresent.FVS0 6 11,FVS0 812andFVS12 12havebeenappliedinthein dustriesofaviationandaerospacetomeettheneedsofadvancedaircraftsforlightweightstructuralmaterialswithhighspecificstrength ,highspecificstiffnessandexcellentthermalstability[14 ] .Theblanksofrapidlysolidifiedheat resistantalu minumalloywereprocessedbyusingpl…     

Crystallization process in rapidly solidified Al-Nd-Ni amorphous alloy prepa red by melt spinning

1　INTRODUCTIONIntherecentfew years ,Al richmetallicglasshasbeenpaidmoreandmoreattentiontointhenovelmaterialsresearchfield ,notonlyduetoitshighstrength ,hardnessandlowdensity ,butalsobecauseanew typeAl basednanophasecompositecanbeob tainedfromitbypartialcrystallization[17] .ManyAl basedamorphous/nanocrystallinealloyscontainingrareearth(RE =La ,Y ,Ce ,Nd ,etc)andtransitionmetal(TM =Fe ,Co ,Ni,etc)elementshaveanattractivecombinationofmechanicalproper ties .Ithasbeenreportedthatmanyofth…     

新型铝合金阳极电化学性能与组织研究

研制了两种新型铝合金阳极材料；用恒电流方法和动电位方法测定了铝合金阳极在碱性氯化钠（25％KOH＋3．5％NaCl）介质中的电化学性能；用金相显微镜、扫描电子显微镜观察了新型铝合金的微观组织和阳级溶解后的表面腐蚀状态。结果表明：固溶于铝基体的微量合金化元素Ga、In及其适量均匀分布的第二相，可以破坏铝氧化膜的致密结构，促使铝基体的正常溶解，减少铝阳极极化，使铝合金阳极的稳定电极电位变得更负；加入能改变铝基体中杂质的存在状态和降低杂质含量的合金化元素Mg等，可以改善铝阳极的腐蚀均匀性，降低自腐蚀速度，提高阳极利用率。     

Devitrification behaviour of rapidly solidified Al87Ni7Cu3Nd3 amorphous alloy prepared by melt spinning method

Rapidly solidified Al87Ni7Cu3Nd3 amorphous alloy was prepared by using melt spinning. Its calorimetric behavior was characterized by using differential scanning calorimeter in a continuous or isothermal heating mode. phase transformation was investigated, with a special interest in primary crystallization, by using an in-situ examination of X-ray diffractometry （XRD） and high resolution transmission electron microscopy （HRTEM）. The results show that, the whole devitrification of rapidly solidified Al87NiyCu3Nd3 amorphous alloy involves two main processes of primary crystallization and secondary crystallization that consist mainly of two reactions. For primary crystallization, the apparent activation energies, EIso and EKis and growth activation energies Eg are about 153, 166 and 288 kJ/mol, respectively. The interdiffusion of Al atoms is a rate-controlled step of formation of the a（Al） particles, but slow diffusion of Ni and Nd atoms plays a significant role in retarding growth of the α （Al） particles. For secondary crystallization, EIso, EKis and Eg of the first reaction are about 291,208 and 290 kJ/mol, and those of the second reaction are about 367, 269 and 372 kJ/mol. The two reactions of secondary crystallization are controlled mainly in an interface-controlled three-dimensional mode, depending mainly on slow diffusion of Ni and Nd atoms.     

电解质组成对铝合金阳极性能的影响

研究了室温下(25℃),4mol/L NaOH 3mol/L NaAlO2介质中,添加Na2SnO3、In(OH)3及Na2SnO3 In(OH)3复合物对铝合金性能的影响。用排水法测试了铝合金电极的析氢速度,用恒电流方法和动电位方法测试了电化学性能。结果表明,4mol/L NaOH 3mol/LNaAlO2介质中,Na2SnO3、In(OH)3及Na2SnO3 In(OH)3混合物能降低铝合金电极自腐蚀速率;恒电流放电时,Na2SnO3使铝合金电极稳定电位稍有正移,In(OH)3和Na2SnO3 In(OH)3混合物使铝合金电极稳定电位明显正移。     

溶胶-凝胶法制备Al2O3·ZrO2复合陶瓷涂层研究

用溶胶-凝胶(Sol-gel)法以Al(NO3)3·9H2O,ZrOCl2·8H2O为原料,乙醇为溶剂,在不锈钢表面制备了xAl2O3·yZrO2复合陶瓷涂层.研究了基材氧化预处理、溶液纽成、添加剂等对陶瓷涂层组成、性能的影响.结果表明:基材氧化预处理能大大改善涂层与基材的结合强度:涂有xAl2O3·yZrO2陶瓷涂层的材料具有较不锈钢更优良的抗高温氧化性能.     

ZrO2@Al2O3陶瓷涂层耐蚀性能研究

用溶胶－凝胶（sol-gel)法在不锈钢表面制备xZrO2.yAl2O3陶瓷涂层,用X射线衍射（XRD）和扫描电子显微镜能谱仪分析了涂层组成与结构;用金相显微镜观测了涂层的孔隙率;用浸泡法和高温抗氧化性试验研究了涂层的耐腐蚀性能。结果表明：xZrO2.yAl2O3涂层随二组分含量的趋近,结构从晶态转变成微晶与玻璃态混合组成,直至完全的玻璃化,涂层致密度提高,耐高温和耐腐蚀性能依次增强。     

快速凝固AlFeX耐热铝合金喷射沉积坯锻造成型工艺试验研究

喷射沉积AlFeVSi合金锭坯需要采用高温（450℃）锻压来实现致密化．通过沿不同取向锻压试验了解了喷射沉积坯及其压实坯的变形能力和锻造损伤情况，采用钢包套锻造工艺制备了完全致密化的喷射沉积Al-9．20Fe-1．37V-2．30Si合金锻件．通过金相、透射电镜、扫描电镜、力学性能检测等研究手段研究了锻造变形对喷射沉积A1FeVSi合金锻坯组织性能的影响．结果表明，喷射沉积AlFeVSi合金坯可以通过锻压变形实现致密化，达到冶金结合状态．喷射沉积AlFeVSi合金压实坯锻造道次压下率可以确定为20—40％，锻造加载方向最好是垂直于喷射沉积原坯沉积面，且需增加可塑性包套来限制侧表面的自由变形．采用钢包套自由锻造工艺可以在累积78％的压缩变形率条件下制备具有良好组织性能的锻造制品．     

高强铝合金的研究现状及展望

对高强铝合金的发展过程进行了简要的回顾，对其研究现状进行了全面评述，并提出了几个在今后的研究及应用中需要重点解决的问题。