用溶胶－凝胶法在碳纤维表面涂覆Al2O3

本文研究用溶胶-凝胶方法在碳纤维表面涂覆Al₂O₃,的工艺对涂层性能、结构及对纤维强度、抗氧化性能等的影响。结果表明:所配溶胶质量好,涂覆工艺合适,可在纤维表面得到均匀、连续的Al₂O₃,涂层;该涂层不仅改善了纤维的抗氧化性能,而且还能保持纤维原有的强度;改善与熔铝的润湿性,为复合材料的制备提供方便。     

Al2O3/Al-4.5Cu-Ce合金复合材料的界面现象

本研究采用座滴法和电子探针探讨了Al-4.5Cu-Ce合金的表面张力及其与Al₂O₃的界面润湿性、界面结构、界面结合方式和强度.得出:饰降低Al-4.5Cu合金的表面张力,提高Al₂O₃/Al-4.5Cu合金的润湿性和界面剪断应力;铈改善润湿性的机制是在界面上的吸附与富集,未发现铈与Al₂O₃的界面反应产物,界面仍属于直接结合界面.     

射频磁控溅射钛镀层与陶瓷界面的X射线光电子能谱研究

本文采用XPS配合Ar+离子原位刻蚀研究了用射频磁控溅射法制备Ti/Al₂O₃(0001),Ti/Al₂O₃(多晶)和Ti/MgO(001)体系的界面结构。结果表明,在Ti/Al₂O₃体系的界面处存在Al3+的还原态和Ti的氧化态,且在刻蚀过程中,Al3+的还原态出现在Ti的氧化态之前。用相同方法制备的Ti/MgO界面没有产生类似的界面反应。     

Fe－40Al合金与Al2O3陶瓷的界面润湿现象

本文采用座滴法研究了金属间化合物Fe-40 Al与Al₂O₃陶瓷的润湿性及界面的相互作用,重点考察了温度、保温时间以及合金元素对Fe-40A1合金/Al₂O₃润湿行为和界面反应的影响。     

SiO2玻璃原位反应合成Al/Al2O3复合材料

利用SiO₂玻璃具有易近成型、致密及各向同性的特点,通过SiO₂玻璃与铝熔体间的反应合成了Al/Al₂O₃复合材料,克服长期以来在合成Al/Al₂O₃复合材料时均采用颗粒反应物的局限。反应产物是一种组织均匀致密的Al 与Al₂O₃互为网络的Al/Al₂O₃陶瓷基复合材料。反应温度升高,整个反应产物中的Al的体积分数上升。Al/Al₂O₃复合组织在三维空间的真实形态中存在着Al相被Al₂O₃完全包围的形态,证明了网络状Al₂O₃组织形成的烧结机理。与合成Al/Al₂O₃的其它工艺相比,本工艺可在1000℃的较低温度进行,并具有反应速度快、断裂韧性和抗弯强度值高的特点。     

碳化硅与氧化铝界面化学稳定性研究

借助最新最权威基本的热力学数据,按化学平衡理论,分析SiC和Al₂O₃之间可能发生的化学反应,定量计算SiC中不同C活度、不同固相产物活度,不同温度下SiC和Al₂O₃间诸反应各气相产物分压和分压总和,精确分析SiC和Al₂O₃界面的热力学稳定性,提供一个大气压惰性气体环境SiC和Al₂O₃界面的热力学失稳判据,为SiC材料研究者提供可靠的参考资料。     

新型陶瓷基复合超疏水涂层的制备及其性能

为了研究开发新型超疏水涂层的制备方法,改善涂层的结构与性能,以Al₂O₃-40%TiO₂(AT40)、PFA(全氟烷氧基乙烯基醚共聚物)粉末为原始材料,采用大气等离子喷涂(APS)技术,并调整电流、氩气流量等喷涂参数,在铝合金基体表面制备了两种不同的AT40/PFA复合超疏水涂层。利用相对应的测试仪器及分析手段对喷涂态涂层的相组成、显微结构、摩擦系数及基本性能等进行了表征分析。结果表明,两种涂层的相组成均为C₂₀F₄₂、Al₂TiO₅及少量的γ-Al₂O₃、α-Al₂O₃相;涂层表面均为圆形和椭圆形的粒状突起结构,其中突起结构的表面均存在类似荷叶表面结构的二元微纳米乳突结构,其表面粗糙度为9.3 μm和12.41 μm;所得涂层具有良好的综合性能,与水的静态接触角均达到了150°以上,滚动角为4~5°;在其他参数不变的情况下,随着电流的增大及氩气流量的减小,涂层中的陶瓷相含量增加,涂层的粗糙度、摩擦系数、显微硬度及结合强度均增大。     

陶瓷颗粒增强镍合金复合涂层冲蚀磨损的试验研究

以WC,ZrO₂,Cr₂O₃和Al₂O₃陶瓷颗粒为增强相,镍合金粉末为基体,运用等离子喷涂技术制备四种陶瓷/镍合金复合涂层。采用冲蚀磨损试验机和正交试验方法,进行陶瓷颗粒相浓度、磨粒粒度、冲蚀角和速度对陶瓷颗粒/镍合金复合涂层抗冲蚀磨损性能影响的试验研究。采用表面形状测量仪对陶瓷颗粒/镍合金复合涂层磨损表面形貌进行测量和分析。试验结果得到WC,ZrO₂,Cr₂O₃和Al₂O₃四种陶瓷颗粒/镍合金复合涂层冲蚀磨损率的经验关联式。     

氧化铝体积分数对Al2O3f+Cf/ZL109混杂复合材料干滑动摩擦磨损行为的影响

利用挤压铸造法制备了Al₂O_3f+C_f/ZL109短纤维混杂金属基复合材料,并探讨了Al₂O₃纤维对该混杂复合材料干滑动摩擦磨损行为的影响。结果表明:混杂复合材料的摩擦系数以及从轻微磨损到急剧磨损转变的临界载荷均随着Al₂O₃体积分数的增加不断增大。在轻微磨损阶段,复合材料的主要磨损机制为犁沟磨损和层离,且Al₂O₃体积分数为12%时混杂复合材料的磨损率最低。发生严重磨损时,基体和复合材料的磨损机制均为严重的粘着磨损。     

硅酸铝短纤维增强AZ91D复合材料的界面微观结构及力学性能

以晶化的硅酸铝短纤维（Al₂O₃-SiO₂ ）_sf为增强体、用磷酸铝为预制体粘结剂,通过挤压浸渗工艺制备了（Al₂O₃-SiO₂ ）_sf /AZ91D镁基复合材料。通过光学显微镜、TEM和HREM分析研究了复合材料的界面微观结构和界面反应产物。结果表明：用挤压浸渗法制备的硅酸铝短纤维增强AZ91D镁基复合材料的界面厚度约为100 nm,界面上除有一定数量的MgO颗粒和少量的MgAl₂O₄和Mg₂Si颗粒外, 还有少量的MgP₄等反应产物存在;硅酸铝增强纤维与镁合金基体之间形成了较强界面结合,界面微观结构比较理想。力学性能测试表明,与AZ91D基体合金相比,复合材料的室温抗拉强度提高了约18%,弹性模量提高了约58%。     

ZnAl 2O 4涂覆 Al 18B 4O 33( w)增强 6061Al 复合材料界面结构与拉伸性能

使用溶胶2凝胶法在硼酸铝晶须表面制备 ZnAl 2O 4涂层 , 采用挤压铸造法制备了 ZnAl 2O 4涂覆的硼酸铝晶须增强 6061Al 复合材料。研究了 ZnAl 2O 4涂覆对复合材料界面润湿性、 室温拉伸性能以及高温热暴露后界面热稳定性的影响。试验结果表明: 纳米 ZnAl 2O 4涂覆能够明显提高复合材料的界面润湿性 , 从而提高复合材料的室温拉伸性能; 均匀的 ZnAl 2O 4涂覆能有效地阻碍界面反应 , 使复合材料具有良好的热稳定性能。研究了涂覆对复合材料在铸态及高温热暴露后拉伸断裂行为的影响。未涂覆硼酸铝晶须增强的铝基复合材料在拉伸变形过程中晶须以折断为主 , ZnAl 2O 4涂覆硼酸铝晶须增强的铝基复合材料在拉伸变形过程中晶须以拔出为主。     

Fine structure of coated whiskers in Al18B4O33w/γ-Al2O3/6061Al composite

Sol-gel -Al₂O₃ coating was deposited onto surfaces of aluminum borate whiskers to control the spinel reactions between whiskers and matrix alloys. High-resolution electron microscopy (HREM) observations of the whisker defects and coating structure in the squeeze-cast Al₁₈B₄O₃₃w/-Al₂O₃/6061Al composite were carried out. Stacking faults and edge dislocations in the whiskers were directly observed, and zigzag anti-phase boundaries were also found. A deformation of whiskers along sectional direction was observed, which was determined to be a source of in situ fracture of whiskers. The sol-gel -Al₂O₃ coating was a nanocrystalline material with an average grain size of 5 nm.     

高温熔剂法制备硼酸铝晶须的研究

研究了高温熔剂法制行９Ａｌ２Ｏ３．２Ｂ２Ｏ３的方法，通过正交试验，利用方差和极并分析法对生长硼酸铝晶须的反应条件进行了优化，找出了生长硼酸铝晶须的最佳工艺条件。结果表明，在高温熔剂法制备肥的过程中，反应温度，氧化硼和氧化铝的摩尔配比及恒温时间为主要因素，并在最佳工艺条件下制得晶须的长经比５０～１００。     

In situ synthesis of porous ceramics with a framework structure of aluminium borate whisker

New porous ceramics with a framework structure of aluminium borate (9Al2O3 · 2B2O3) whiskers, in which the whiskers are distributed uniformly and randomly, can be synthesized in situ by firing of a green powder compact of a mixture of aluminium hydroxide, boric acid and an additive of nickel oxide above 1100°C. During firing, the whiskers of aluminium borate grow in situ in the compact, and are bonded together by sintering. The porous aluminium borate consists solely of whiskers, has a porosity of 85%–50%, which corresponds to a volume fraction of whiskers of 15%–50%, and a flexural strength of 2.2–56.1 MPa. Because the whiskers are strongly bonded to other whisker(s), the problem of whiskers scattering, that can be an inhalation hazard, is solved. The aluminium alloy matrix composite using this porous aluminium borate as reinforcement was fabricated by the squeeze-casting method. The tensile strength of the composite material with a whisker volume fraction of 20% can be improved by up to about 90% compared with the unreinforced matrix alloy at 350°C. © 1998 Chapman & Hall     

偶联剂对硼酸铝晶须/双马来酰亚胺性能的影响

应用自行合成的一类新型硼酸酯偶联剂及硅烷偶联剂等对硼酸铝晶须进行表面处理,考察了硼酸铝晶须对双马来酰亚胺树脂体系性能的影响.结果表明,硼酸酯处理后的晶须对材料的改性作用较硅烷更加显著;硼酸铝晶须添加到双马来酰亚胺树脂中后,材料的弯曲强度在晶须含量为5%时达到最大值,而后随晶须含量的增大稍有下降;随晶须添加量的增大材料的弯曲模量和耐热性逐渐提高;经硼酸酯处理的晶须与树脂基体具有更好的界面粘接.     

溶胶-凝胶法Al2O3涂层碳纤维增强铝基复合材料的研制

以异丙醇铝为原料, 经乙酰丙酮改性, 通过水解缩合制得Al₂O₃溶胶, 研究溶胶2凝胶法在碳纤维上涂覆氧化铝陶瓷和制备(涂层) 碳纤维增强铝基复合材料预制丝的连续工艺。采用了IR、TG-DTA、XRD、SEM 等手段对溶胶2凝胶产物、涂层纤维、碳纤维增强铝预制丝进行了分析表征。结果表明: γ-Al₂O₃涂层有效的阻止了氧分子渗入, 与原纤维相比, 涂层纤维的耐高温性能明显提高。涂层后纤维与熔融铝的润湿性和相容性明显改善, 涂层有效的阻止了碳/铝界面反应, 使预制丝强度明显提高。      

硼酸铝晶须/双马来酰亚胺树脂摩擦磨损性能

研究了不同偶联剂及硼酸铝晶须添加量对硼酸铝晶须/双马来酰亚胺复合材料的摩擦磨损性能的影响。结果发现,硼酸铝晶须能有效地提高复合材料的耐磨性,晶须的加入使材料的磨损率明显降低;偶联剂对材料摩擦磨损性能的影响不明显;体系中添加硼酸铝晶须后随摩擦时间的延长复合材料的摩擦系数呈增大趋势。当晶须含量较小时摩擦机制主要是轻微的粘着磨损和疲劳磨损,当晶须含量大于8%时,疲劳磨损占主导地位,同时伴有粘着磨损和磨粒磨损。      

Microscopic examination of the interface region in AC8A/Al18B4O33w composites reinforced with as-received and artificial nitrided Al18B4O33 whiskers

Aimed to control the interfacial reaction in Al₁₈B₄O₃₃/Al composites, the artificial nitridation process is proposed based on thermodynamic calculations, which leads to a 50-nm thick artificial nitrided coating surrounding a Al₁₈B₄O₃₃ whisker. Aluminum (AC8A) matrix composites reinforced with different Al₁₈B₄O₃₃ whiskers were processed and Al₁₈B₄O₃₃ whiskers were used in their as-received form and after artificial nitridation. The interface region between the aluminum matrix and Al₁₈B₄O₃₃ was charactered using transmission electron microscopy. Results show that extensive reaction takes place during the incorporation process between the as-received Al₁₈B₄O₃₃ whiskers and the aluminum matrix and Mg in the base alloy forms MgAl₂O₄ spinel phases. Such interfacial reaction is enhanced after T6 heat treatment. In the case of artificially nitrided Al₁₈B₄O₃₃ whiskers, even though the artificial nitrided coating surrounds the Al₁₈B₄O₃₃ whisker, it can react with the AC8A alloy to produce MgAl₂O₄, but the degree of the interfacial reaction is reduced. The interfacial reaction only consumes the artificial nitrided coating instead of the reinforcement whiskers and the integrity of the whisker is preserved.     

Effects of sintering temperature of whisker preform on the microstructures and tensile properties of Bi(OH)3-coated Al18B4O33 whisker-reinforced aluminum matrix composites

A alumina borate whisker with Bi(OH)₃ coating was prepared by a chemical method. The coated whiskers were sintered at various temperatures. The coated whisker-reinforced pure aluminum matrix composite was fabricated by squeeze casting method. The microstructures of the coated whiskers and coated composites with the different sintering temperature of whisker preform were studied, and the tensile properties of the coated composites at room temperature were also investigated. It can be found that the microstructures of coatings on the whisker surfaces and at the interface in the coated composites are strongly dependent on the sintering temperature of whisker preform. The ultimate tensile strength and elongation to fracture of the coated composites increased with the increasing of sintering temperature of the whisker preform.     

Preparation and characterization of Al18B4O33 + BaPbO3/Al hybrid composite

In this paper, the aluminum borate whisker (ABOw) and BaPbO₃ particles (BPOp)/Al hybrid composite with radiation protection function was fabricated by squeeze casting technique. The microstructure and properties of the hybrid composite were investigated. The test results show that BPOp and aluminum matrix have a reaction, and this reaction forms a coating on the surface of ABOw. The introduction of BPOp increases radiation protection function of the matrix evidently, at the same time, the hybrid composite has better mechanical properties compared with the aluminum matrix and ABOw/Al composite.