【作者】 田浩；

【导师】 耿林；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2007， 硕士

【摘要】 采用BaPbO₃颗粒和2024铝合金,用粉末冶金技术制备了具有辐射防护功能的BaPbO₃/2024Al复合材料。探索了复合材料的制备工艺;利用XRD、SEM和室温拉伸试验对复合材料的组织和性能进行了研究。同时探索了溶胶-凝胶法、沉淀法和室温固相反应法在BaPbO₃颗粒表面包覆Al₂O₃涂层的涂覆工艺;利用XRD、SEM、EDS和TG/DTA分析手段对包覆层和包覆效果进行了分析。试验结果表明:制备的430℃挤压态BaPbO₃/2024Al复合材料抗拉强度可达317Mpa,但复合材料中存在Pb,说明在材料的制备过程中,BaPbO₃与2024Al基体发生反应生成了Pb;在热压温度为430℃时,热压压力为0MPa下,没有发现Pb的生成;但当存在压力时,即使温度降低为400℃依然发生反应生成了Pb,压力促进了反应,并且400℃热压态复合材料不致密。说明为了保证制备出致密的复合材料,通过控制热压温度和热压压力无法避免复合材料中界面反应的发生。在铝溶胶浓度为0.4mol/L,Al₂O₃:BaPbO₃（wt.%）=1:1,pH=3.5-4.1,搅拌时间为30min的工艺条件下,制备出了表面被完全包覆的Al₂O₃涂层,但溶胶-凝胶法包覆Al₂O₃涂层BaPbO₃颗粒中含有氧化铅。沉淀法在BaPbO₃颗粒上包覆Al₂O₃涂层的分析表明:只能将BaPbO₃粉末直接加入到Al（OH）3沉淀中,而不能将硝酸铝溶液加入到碱性的BaPbO₃悬浮液中;随着Al₂O₃与BaPbO₃的重量比（Al₂O₃:BaPbO₃ （wt.%））的增大,包覆效果越好;但沉淀法制备的氧化铝涂层不能完全包覆在BaPbO₃颗粒表面。利用室温固相反应法在BaPbO₃颗粒表面完全包覆Al₂O₃涂层。EDS分析表明:颗粒的表面元素有Al元素,这证明包覆层为Al₂O₃;同时由2024Al与室温固相反应法制得的混合粉末的DTA分析可知,在350℃和500℃之间并无明显的放热和吸热峰,这说明BaPbO₃颗粒表面被完全包覆上氧化铝,氧化铝涂层防止了BaPbO₃颗粒与2024Al的接触,使反应无法进行。更多还原

【Abstract】 The aluminium matrix composites with radioprotection function were fabricated by powder metallurgy using BaPbO₃ powders and 2024Al powders. Preparation technology is studied on impacting interface reaction of composites. The microstructure and properties of the composites were investigated by XRD, SEM and tensile test. The technical parameter is researched on making BaPbO₃ coated by Al₂O₃. The effect of coatings is investigated by XRD, SEM, EDS and TG/DTA.The experimental results indicated that the tensile test shows that the tensile strength of the aluminium matrix composites is 317MPa, and the composites contain Pb, so there are reactions between BaPbO₃ and 2024Al when the composites were fabricated. When the sintering temperature is 430℃and no pressure, there is no reaction between BaPbO₃ and 2024Al, but when the pressure of hot pressing is not 0MPa, even if the temperature is 400℃, there also exit reactions between BaPbO₃ and 2024Al. And composite is unsound. So that shows us for making dense composites, interface reaction did not avoid through controlling the temperature and pressure of hot pressing.When technical parameters are that concentration of Al-sol is 0.4mol/L,Al₂O₃:BaPbO₃ （wt.%）=1:1, pH=3.5-4.1 and mixed for 30min, Al₂O₃ completely coated BaPbO₃ are produced. But PbO is found in BaPbO₃ coated by Al₂O₃.BaPbO₃ coated by Al₂O₃ are produced using chemical precipitation method. There only puting BaPbO₃ powders into Al（OH）3 liquor is suitable, and putting Al（NO3）3 liquor into BaPbO₃ suspending liquid is not suitable. The effect of coatings is better along with the Al₂O₃:BaPbO₃ （wt.%） lager. But Al₂O₃ coating is incomplete coated on BaPbO₃ surface.Al₂O₃ completely coated BaPbO₃ are produced by a humid solid state reaction at room temperature. There is Al element on BaPbO₃ coated by Al₂O₃ by EDS analysis, so this proves the coating is Al₂O₃. DTA analysis of 2024Al+ BaPbO₃ coated by Al₂O₃ shows that there is no exothermic peak and endothermic peak between 350℃and 500℃, and this proves Al₂O₃ is completely coated on BaPbO₃, so contact between BaPbO₃ and 2024Al is impossible and reaction is avoided.更多还原