Al/Al2O3多层膜的表面和界面的分析研究

用热蒸发沉积和自然氧化及加热法制备纳米量级的Al/Al2 O3薄膜和多层膜。用X射线光电子谱仪 (XPS)和透射电镜 (TEM)对样品进行检测。XPS实验说明自然氧化的Al2 O3膜层厚在 2～ 5nm。Al/Al2 O3薄膜及多层膜的O与Al的原子浓度比为 1 4 3～ 1 85。Ar离子刻蚀的XPS实验结果 (刻蚀速率为 0 0 9nm/s)说明 :2个对层的Al/Al2 O3多层膜截面样品具有周期性结构。TEM观察到了 5个对层的Al/Al2 O3多层膜的层状态结构 ,其周期为 4nm。由此说明 ,热蒸发及自然氧化法是制备纳米量级的Al/Al2 O3多层膜的有效方法     

Al/Al2O3多层膜的表面分析与电性能的研究

用热蒸发沉积和自然氧化及加热法制备纳米量级的Al/Al2/O3薄膜和多层膜.本文用X射线光电子能谱(XPS)和紫外光电子能谱(UPS)对样品进行价带能谱的检测与分析.获得的Al/Al2/O3多层膜价带的XPS光电子能谱谱形基本相似;通过对Al/Al2O3三层膜在不同极角的UPS谱线的检测,得到其Ei-(k∥i)关系曲线.此外,测定了低温下的I-U特性,发现纳米量级的Al/Al2O3薄膜具有负阻特性.     

Al/Al2O3多层膜的表面和界面的分析研究

用热蒸发沉积和自然氧化及加热法制备纳米量级的Al/Al2O3薄膜和多层膜.用X射线光电子谱仪(XPS)和透射电镜(TEM)对样品进行检测.XPS实验说明自然氧化的Al2O3膜层厚在2～5 nm.Al/Al2O3薄膜及多层膜的O与Al的原子浓度比为1.43～1.85.Ar离子刻蚀的XPS实验结果(刻蚀速率为0.09 nm/s)说明2个对层的Al/Al2O3多层膜截面样品具有周期性结构.TEM观察到了5个对层的Al/Al2O3多层膜的层状态结构,其周期为4 nm.由此说明,热蒸发及自然氧化法是制备纳米量级的Al/Al2O3多层膜的有效方法.     

不同调制周期TiAlSiN/Mo2N多层膜的微观结构、力学和摩擦性能研究

采用射频磁控溅射制备不同调制周期的TiAlSiN/Mo2N多层膜。利用X射线衍射,扫描电镜,能量弥散X射线谱,纳米压痕仪及摩擦试验机对薄膜的成分,相结构,力学及室温摩擦性能进行分析。结果表明,不同调制周期的TiAlSiN/Mo2N多层膜为fcc与hcp混合结构,不同调制周期的TiAlSiN/Mo2N多层膜硬度均大于单层TiAlSiN和Mo2N薄膜,且TiAlSiN/Mo2N多层膜的硬度与弹性模量随调制周期的影响不大,硬度稳定在29 GPa左右,室温条件下,以Al2O3为摩擦副的TiAlSiN/Mo2N多层膜平均摩擦系数平均摩擦系数均低于单层TiAlSiN、Mo2N薄膜,且随调制周期的增大逐渐降低,其最低平均摩擦系数为0.42,对应调制周期为12 nm。     

Al／Al2O3多层膜的表面和界面的分析研究

用热蒸发沉积和自然氧化及加热法制备纳米量级的Al/Al2O3薄膜和多层膜。用X射线光电子谱仪（XPS）和透射电镜（TEM）对样品进行检测。XPS实验说明自然氧化的Al2O3膜层厚在2－5nm。Al/Al2O3薄膜及多层膜的O与Al的原子浓度比为1.43-1.85。Ar离子刻蚀的XPS实验结果（刻蚀速率为0.09nm/s)说明：2个对层的Al/Al2O3多层膜截面样品具有周期性结构。TEM观察到了5个对层的Al/Al2O3多层膜的层状态结构，其周期为4nm。由此说明，热蒸发及自然氧化法是制备纳米量级的Al/Al2O3多层膜的有效方法。     

Al／Al2O3多层膜的表面分析与电性能的研究

用热蒸发沉积和自然氧化及加热法制备纳米量级的Al/Al2O3薄膜和多层膜。本用X射线光电子能谱（XPS）和紫外光电子能谱（UPS）对样品进行价带能谱的检测与分析。获得的Al/Al2O3多层膜价带的XPS光电子谱谱形基本相似；通过对Al/Al2O3三层膜在不同极角的UPS谱线的检测，得到其Ei-(Ki∥）关系曲线，此外，测定了低温的I－U特性，发现纳米量级的Al/Al2O3薄膜具有负阻特性。     

Ti(CN)/TiC/Al2O3/TiN多层涂层的结构和界面结合力研究

采用中温、高温复合化学气相沉积技术(MHCVD)在WC- (6％wt)Co硬质合金基体表面制备了Ti(CN)/TiC/Al2O3/TiN 多层陶瓷涂层.通过光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和数显显微硬度计等手段分析多层陶瓷涂层的表面及断面形貌、物相组成、显微硬度;采用表面划痕实验,结合形貌观察及X射线能谱分析(EDS)研究多层陶瓷涂层/硬质合金基体的界面结合力及其影响因素.结果表明:Ti(CN)/TiC/Al2O3/TiN 多层陶瓷涂层结构均匀致密,涂层后硬质合金的显微硬度明显提高,约2600 HV,多层陶瓷涂层与基体界面结合良好,划痕实验显示临界载荷高达105 N,多层陶瓷涂层界面间的原子扩散作用对涂层/基体界面附着力有较大贡献,而涂层内部少量Ti2O3、W6Co6C 等物相的存在对提高界面结合力也有帮助.     

纳米Al2O3增强磷化膜耐磨性的研究

将α型纳米Al2O3加入到磷化液中,选择合适的分散剂,在一定的温度范围内进行磷化,通过共沉积使纳米材料包裹在磷化膜层中,以达到改善磷化膜质量、提高膜层性能的目的.研究了磷化温度、时间、分散剂和纳米用量及酸度调节剂Na2CO3 对反应的影响,通过正交试验得出最优磷化工艺参数为:18.0 g/L ZnO,1.0 g/L Ni(NO3)2,16 mL/L HNO3, 3.0 g/L Ca(NO3)2,28.5 mL/L H3PO4,5.0 g/L Mn(H2PO4)2,2.0～5.0 g/L 柠檬酸,1.0～5.0 g/L 酒石酸,3.0～5.0 g/L 复合促进剂,11.0 g/L Na2CO3,4.0 g/L α型纳米Al2O3 ,分散剂A 2.5 g/L,磷化温度80 ℃,磷化时间12 min.经X射线、扫描电镜、电子探针等测试分析发现,加入的α型纳米Al2O3在磷化膜层中基本均匀分布.用细纱纸摩擦法测试磷化膜的耐磨性,发现加入α型纳米Al2O3的磷化膜耐磨性明显增强.     

大气等离子喷涂工艺参数对Al2O3涂层性能的影响

为了提高燃烧器工艺烧嘴的使用寿命,在UMCo-50基材表面大气等离子喷涂Al2O3层。采用正交试验法对喷涂工艺参数进行了优化,运用微观形貌分析、X射线衍射分析并结合强度及显微硬度等测试方法,系统研究了喷涂主气流量、功率和送粉量对AI2O3涂层综合性能的影响规律。结果表明:喷涂主气流量、功率和送粉量对Al2O3涂层性能具有交互性影响,在40L/min Ar,48 kW和30g/min条件下可以获得性能较好的Al2O3涂层,极大地提高了UMCo-50基材的抗高温氧化和耐磨性能,使之具有广阔的应用前景。     

化学镀Ni-P/纳米Al2O3复合镀层结构及性能研究

通过化学复合镀工艺制备了Ni-P/纳米Al2O3复合镀层.利用扫描电子显微镜(SEM)和X射线衍射(XRD)对复合镀层的表面形貌及结构进行了测试,研究了纳米Al2O3添加剂、Al2O3复合量质量分数、热处理等工艺条件对Ni-P/纳米Al2O3复合镀层结构与性能的影响.结果表明,Ni-P/纳米Al2O3复合镀层的硬度和耐磨性高于Ni-P合金镀层,而且随着Al2O3复合量的增大镀层硬度和耐磨性增加.当纳米Al2O3复合量质量分数为10.1%时,Ni-P/纳米Al2O3复合镀层的硬度较Ni-P合金镀层增大28%,磨损失重减少20%以上.400℃热处理后,复合镀层结构由非晶态转变为晶态,镀层硬度由570 HV增大到1 185 HV,耐磨性也进一步提高.     

Nitridation-assisted Al infiltration for fabricating Al composites

In this study, we developed an Mg-, vacuum-, and pressure-free process for manufacturing Al-based composites via nitridation-assisted spontaneous infiltration of molten Al. In this process, the wettability between molten Al and ceramic reinforcement was significantly enhanced by nitridation via heating and surface modification of the Al particles; this provided a sufficient capillary force (i.e., negative curvature) for spontaneous infiltration of molten Al. The proposed process can generate composites based on Mg-free Al matrices and is relatively versatile in terms of the type, volume fraction, and morphology of the reinforcement material. Furthermore, the properties of the final composites can be modified by controlling their degree of nitridation, thereby expanding the material scope and their corresponding application fields.     

低价硫化铝法从氧化铝直接炭还原制铝的动力学研究

低价硫化铝法从氧化铝直接炭还原制铝的动力学过程极为复杂,过程的前期受界面化学反应控制,过程后期受扩散过程控制,并求得不同时期的活化能,反应前期:E1=63.81 kJ/mol(6.67 Pa)、E2=50.82 kJ/mol(66.7 Pa)、E3=54.72 kJ/mol(666.7 Pa)、E4=39.61 kJ/mol(1333 Pa);反应后期:E*1=112.90 kJ/mol(6.67 Pa)、E*2=89.92 kJ/mol(66.7 Pa)、E*3=97.32 kJ/mol(666.7 Pa)、E*4=51.83 kJ/mol(1333 Pa).从动力学的角度提出了反应的较佳条件.温度、真空度的提高一方面可增大反应速率,但另一方面却加大了硫化铝的挥发,仅从增大速率而言,温度应大于1100 ℃,真空度应优于1333 Pa为宜.     

Thermal stability of Al/Al11 Ce3 and Al/Al11 La3 /Al3 Ni eutectics obtained by Bridgman growth

Abstract

The effects of extended treatment at 500°C on microstructure and microhardness of Al/Al₁₁ Ce₃ and Al/Al₁₁ La₃ /Al₃ Ni eutectics in Al–12·1Ce and Al–11·3La–5·4Ni (wt-%) alloys Bridgman solidified at 0·1 mm s^-1 are reported. Coarsening of Al/Al₁₁ Ce₃ occurs more rapidly in some eutectic cells than others such that areas coarsening at a lower rate still form 10% of the microstructure even after 3024 h. It was found that Al/Al₁₁ La₃ /Al₃ Ni showed accelerated coarsening at eutectic cell boundaries but association between Al₁₁ La₃ and Al₃ Ni still remained within cells and at cell boundaries even after 3024 h. Associated decreases in hardness for Al/Al₁₁ Ce₃ were similar to fibrous Al/Al₆ Fe of similar initial spacing subjected to the same heat treatment. The 30% higher initial hardness of Al/Al₁₁ La₃ /Al₃ Ni largely persisted even after 3024 h at 500°C.     

钪在铝及铝合金中的作用

总结了Sc在铝及铝合金中对合金组织、力学性能、热稳定性、焊接性能和抗腐蚀，性能的影响。Sc在铝合金中是有效的晶粒细化剂、再结晶抑制剂和改善焊接性能的添加剂；Sc可以细化铝合盒晶粒，提高合盒的力学性能和再结晶温度，增强铝合金的热稳定性，改善铝合盒的焊接性能和抗腐蚀性能；分析了Sc在铝合盒中的作用机理。     

Al and Ti/Al contacts on n-GaN

Al(60 nm) and Ti(40 nm)/Al(160 nm) metal layers have been deposited by thermal evaporation onto n-GaN epitaxial layers grown by metal organic chemical vapour deposition (MOCVD) on a c-plane sapphire substrate. The samples have been annealed at 300, 400, 700 or 900 °C for 10 min in vacuum. The microstructural and electrical properties of the contacts have been investigated by electron microscopy, X-ray diffraction and by current-voltage measurements. As-deposited Al and Ti/Al contacts were rectifying with Schottky barrier heights below 0.35 eV and 0.38 eV, respectively. After heat treatment at 300 °C and 400 °C both contacts exhibited linear current-voltage characteristics. After annealing at 700 °C Al contacts became rectifying with a barrier height of 0.42 eV, while Ti/Al contacts remained nearly linear at the same temperature. The electrical characteristics and XRD analysis indicated that the upper metal in Ti/Al contact diffused in the Ti layer already during deposition. Cross-sectional transmission electron microscopy revealed that in the case of Ti/Al contacts, the continuity of the Ti layers ceased when annealing above 700 °C. X-ray diffractions showed, that a Ti₂N interface phase formed in Ti/Al contacts at 700 and 900 °C, and an AlN interface phase developed in the same contact at 900 °C.     

Transport Properties of the Tunnel Junctions Al1-xCox/{Al1-xCox-oxide}/Al

The oxides of Al1-xCox (x=0,0.25,0.5,0.75, and 1.0) alloys were chosen as barrier materials in this work. The tunnel junction consists of the bottom electrode Al1-xCox and the top electrode Al with an insulating layer { Al1-xCox-oxide} which was formed by natural oxidation in a baking-box at 333K. The oxidation time for forming an Al1-xCox-oxide layer on the surface of the bottom Al1-xCox layers were optimized.The resistance of Al1-xCox/{ Al1-xCox-oxide}/Al tunnel junctions varied between 101 and 106 Ω measured at 1 my and 4.2 K. The effective barrier height and width of insulating layers Al1-xCox-oxide ( x=0.25, 0.5, and 0.75 )varied between 0.6 and 2.7 eV and between 1.3 and 2.1 nm. It is shown that the thin oxide layer of Al1-xCox alloys can be chosen as barrier materials.     

铝合金时效成形及时效成形铝合金

介绍了铝合金时效成形的方法、基本原理、工艺特点及应用情况,概括了国外研究铝合金时效成形工艺及相关可时效成形铝合金的现状,重点阐述了时效成形对铝合金微观组织结构的影响.