【作者】 胡新鸽；

【导师】 邱克辉；

【作者基本信息】 成都理工大学 ， 金属矿产与金属材料， 2009， 硕士

【摘要】 Mg₂TiO₄具有低介电常数、介电损耗和优良的微波介电性能,但目前对于Mg₂TiO₄作为电子陶瓷的研究仍然很少,对其发光性能的研究尚未见相关文献报道。本论文以钛酸四丁酯和硝酸镁为原料,分别以柠檬酸和尿素为燃料,低温燃烧法合成了Mg₂TiO₄粉体并研究了采用燃烧法合成制备钛酸镁Mg₂TiO₄电子陶瓷粉体材料的工艺条件,并通过XRD、SEM分别对合成样品的物相组成、结构、颗粒大小、形貌等微观特征进行了表征和分析;研究了掺杂稀土离子的种类及其掺杂量、燃料种类、煅烧温度、保温时间、乙二醇和柠檬酸用量对其性能的影响,并采用荧光光度计对粉体的发光性能进行了表征和初步探讨。XRD衍射图分析表明:燃料种类对物相组成的影响最大。以尿素为燃料合成的样品纯度高,物相组成为纯的Mg₂TiO₄（PCPDF卡号为02-1157）;以柠檬酸为燃料合成的样品为Mg₂TiO₄,含有少量的MgTiO₃和MgO。煅烧温度、保温时间同样影响样品的物相,以柠檬酸为燃料时,随煅烧温度的升高和保温时间的增加,Mg₂TiO₄的衍射峰变得尖锐而且强度增强,影响较为明显;以尿素为燃料时,Mg₂TiO₄的衍射峰随温度升高的变化较明显,但是随保温时间增加的变化影响不大。可见,适当提高温度和延长保温时间都有利于合成较纯的Mg₂TiO₄。SEM照片显示,燃料种类对样品的微观形貌影响较大。尿素为燃料时,样品的微观形貌为球团状,柠檬酸为燃料时,样品的微观形貌为片状。FL光谱分析结果表明,Mg₂TiO₄的激发光谱为峰值位于338nm的宽带谱,其发射峰位于400nm和661nm,为Mg₂TiO₄的本征发射,其中400nm为Mg₂TiO₄的主发射峰,位于紫光区,661nm为次发射峰,位于红光区,因此发光颜色为紫红色。掺杂稀土离子的种类及其掺杂量、燃料种类、煅烧温度、保温时间、乙二醇的量、柠檬酸的量对Mg₂TiO₄的发光性能都有影响。稀土离子的掺入有助于提高钛酸镁的发光性能,掺Dy³⁺和Nd³⁺的发光效果最好,掺Dy³⁺、Nd³⁺、Tb³⁺对400nm处的紫光发射有利,掺Pr³⁺则有利于661nm处的红光发射;以尿素为燃料合成样品的发光亮度和强度强于柠檬酸体系合成的样品;煅烧温度、保温时间、掺杂浓度影响样品的发光性能,随煅烧温度提高、保温时间和掺杂浓度的增加,发光亮度提高,但并非煅烧温度越高,保温时间越长,掺杂浓度越大,样品的发光性能就越好。猝灭浓度0.05moL%,合适的保温时间20min。结果表明,燃烧法合成钛酸镁Mg₂TiO₄电子陶瓷粉体材料的较佳工艺条件为:尿素为燃料,尿素:[Mg+Ti]=1.5:1,乙二醇:尿素=4:1,掺入稀土离子的量为0.05moL%,煅烧温度为900℃,保温时间为20min。对Mg₂TiO₄的合成制备技术、性能以及用途的研究还属于一个新的领域,本研究对应用领域的拓展以及新产品的开发,以及利用我国丰富的钛和镁资源,发展新产业具有非常重要的现实意义。同时,我国钛和镁的矿产资源非常丰富,有着发展钛和镁金属材料、无机非金属材料如钛酸镁电子陶瓷材料、荧光材料、光学功能材料等新型钛镁材料的资源优势。更多还原

【Abstract】 Mg₂TiO₄ has minor dielectric constant , dielectric spoilage and excellent microwave dielectric properties, but researches on Mg₂TiO₄ used as electroceramics are still very few , literatrues about the luminescent properties haven’t been found. In the dissertation , Mg₂TiO₄ of high purity and better luminescent effect can be synthesized at 900℃by combustion method using urea as the fuel , the temperature can be reduced by 400℃compared with the temperature 1300℃of solid state reaction in literature , so the cost can be greatly reduced.In the dissertation , the magnesium titanium oxide（Mg₂TiO₄） electroceramics powders has been synthesized via combustion method by using tetra-n-butyl titanate and magnesium nitrate as raw materials, citric acid and urea as the fuels respectively. And also, researches on technological conditions of the synthesis of Mg₂TiO₄ electronic ceramics are studied , simultaneously , phase composition, construction, particle size, appearance and other microscopic features are characterized and analysized by XRD and SEM. The influence of the factors on the properties of Mg₂TiO₄ are studied , such as the variety of the doping ions and its doping amount , the sort of fuels , calcination temperature , the holding time , the amount of ethylene glycol and the quantity of citric acid , and also the luminescent properties are investigated by the fluorescence spectrophotometer.The XRD shows that the kinds of fuels have the greatest influence on the phase composition. When using urea as the fuel , Mg₂TiO₄ of high purity can be synthesized , and the phase composition is pure Mg₂TiO₄ , and its PCPDF card number is 25-1157 ; but when using citric acid as the fuel , the sample is constitued by Mg₂TiO₄ , little MgTiO₃ and MgO . Calcination temperature , heat holding time also infulences the phase of the sample , when citric acid is used as the fuel , the diffraction peak of Mg₂TiO₄ is sharper and the intensity is stronger as the temperature and the heat preservation time raises , the effect is obvious ; when urea is used as the fuel , the diffraction peak of Mg₂TiO₄ is visible as the temperature raises , but isn′t apparent as the heat preservation time prolongs. So, raising temperature and prolonging heat preservation time help to get purier Mg₂TiO₄ for the system of magnesium titanate .The SEM photos show that the kind of fuels has the greater influence. When urea is used as the fuel , the appearance is regiment and when using citric acid as the fuel , the micro- appearance is schistose .The FL spectrums show that the excitation spectrum of Mg₂TiO₄ is a broad-band spectrum , and the peak value is 338nm , the emission peaks are located at 400nm and 661 nm , they are the intrinsic emission of Mg₂TiO₄ , the peak at 400 nm is the main emission peak , which is located in purple light region, and the peak at 661 nm is the secondary emission peak ,which is located in red light region, so the color of the Mg₂TiO₄ is reddish purple. The variety of the doping ions and its doping amount ,the sort of fuels ,calcination temperature ,the holding time ,the amount of ethylene glycol and the quantity of citric acid all have effects on the luminescent properties of Mg₂TiO₄. We find that the doping of rear earth ions helps to enhance the properties of luminescence of Mg₂TiO₄. The samples doped by Dy³⁺ and Nd³⁺ have the best luminescent effect, doping Dy³⁺ , Nd³⁺and Tb³⁺ favor for the purple light emission of 400nm , doping Pr³⁺ is in favor of the red light emission of 661 nm . The system that uses urea as the fuel have the better luminescent brightness and intensity compared with the system using citric acid as the fuel. The properties of luminescence is better and better as the calcination temperature ,heat preservation time and the amount of doping concentration raises , but it has a quench temperature 900℃, quench concentration 0.05moL%, an optimal heat preservation time 20min. The results show that the better technological conditions of preparing Mg₂TiO₄ electronic ceramics powders by combustion can be got when the ratio of urea to [Mg+Ti] , ethylene glycol to urea is respectively 1.5 and 4.0, the doping amount of rear earth ions equals to 0.05moL% , the calcining temperature is 900℃, heat preservation time lasts 20 minutes.Therefore, researches on Mg₂TiO₄ have great importance. The preparation technology , properties and application is still a new field , it will be very important practical to the development of the open up of application field and the development of new products ,and also it has great practical significance to develop new industries using the rich resources of titanium and magnesium . Simultaneously, we have the advantage of resources to develop metal materials of titanium and magnesium,magnesuim titanate electronic ceramics materials , optical functional materials and so on .更多还原