【作者】 王晓芳；

【导师】 谷臣清；

【作者基本信息】 西安理工大学 ， 材料学， 2007， 硕士

【摘要】 ZrW₂O₈、ZrV₂O₇是具有各向同性,负热膨胀系数大且响应温度范围宽的两类负热膨胀材料,但均存在一定不足。本项研究旨在通过两者的复合克服其不足,发挥各自的优势,并在此基础上研究ZrW₂O₈/Cu、ZrV₂O₇/Al的复合技术及其热膨胀特性,以期研制热膨胀特性可控,更便于应用的低热膨胀材料,扩大其应用领域。ZrV₂O₇与ZrW₂O₈的复合,采用氧化物固相煅烧合成法与液相法预制前驱体粉末,再经煅烧合成两种方法进行。通过对实验产物进行结构（XRD）、组织（SEM）、电子能谱成分分析（EPS）和热膨胀特性测试分析,结果表明:两种方法均可实现ZrV₂O₇与ZrW₂O₈之间的复合。在650℃～700℃煅烧合成,可获得Zr（V、W）xOy质复合陶瓷,其结构保持与ZrV₂O₇完全相同的点阵结构,属于一种掺杂有W6+的ZrV₂O₇质陶瓷材料,此材料仍保持着ZrV₂O₇的负热膨胀特性。在20℃～120℃温度范围内的热膨胀系数显著下降,降至2.9×10-6/℃,已接近理想电子封装材料的要求。而且,采用液相法预制前驱体—煅烧合成制备的复合产物的烧结性能好,更有利于工程应用。ZrW₂O₈与Cu的复合,采用向ZrW₂O₈前驱体/Cu粉复合烧结工艺过程中引入CuO与Al的放热反应工艺技术。经对产物进行XRD、SEM、EPS和热膨胀特性测试分析,结果表明:采用该工艺技术可制备出组织致密,形成具有Cu网架结构的ZrW₂O₈、Al2O3/Cu基复合材料。该材料在30℃～60℃间为零膨胀;60℃～300℃间的平均线膨胀系数仅为4.2×10-6/℃,显示出非常优异的低热膨胀特性。ZrV₂O₇与Al的复合,采用ZrV₂O₇、Al混合粉末无压渗透烧结及ZrV₂O₇前驱体包覆Al粉末烧结合成两种工艺方法进行。经对实验产物进行XRD、SEM、EPS和热膨胀特性分析测试,结果表明:采用ZrV₂O₇前驱体包覆Al粉末烧结合成的ZrV₂O₇/Al复合材料,其中的ZrV₂O₇纯度更高,ZrV₂O₇与Al之间具有更好的界面结合性和热膨胀特性。此材料在室温～120℃间平均线膨胀系数为18.0×10-6/℃;120～400℃间为4.04×10-6/℃;400～500℃间为7.3×10-6/℃。虽仍具有高的正热膨胀系数,但较Al的热膨胀率（23.0×10-6/℃）已显著下降。在此基础上,采用粉末冶金法制备的ZrV₂O₇/Al梯度材料亦呈现出高的组织致密性,并表现出良好的抗热震性能。更多还原

【Abstract】 ZrW₂O₈ and ZrV₂O₇ demonstrated the isotropic and a large negative thermal expansion coefficient over a wide range of temperatures, but they both existed certainly defects. The purpose of this research aimed to overcome the inadequacies of the two compounds, and displayed their respective advantages. In order to facilitate the application of the thermal expansion materials and expand its application areas, compound technology and thermal expansion characteristics of ZrW₂O₈/Cu、ZrV₂O₇/Al were further studied.ZrV₂O₇ and ZrW₂O₈ were compounded by two different methods: directly-calcined synthesis from oxides and calcined synthesis with the precursor. The results by XRD、SEM、EPS and thermal-expansion test indicated that the composite can be achieved by both methods. The ceramics of Zr（V、W）xOy was obtained from 650℃～700℃by calcined, and its structure kept the identical lattice structure with ZrV₂O₇. The ceramics kept NTE and belonged to one kind of doping W6+ in ZrV₂O₇. But the thermal expansion coefficient was remarkably dropped to -2.9×10-6/℃from 20℃to 120℃, and the thermal expansion coefficient already closed to the request of the ideal electronic packing materials. Moreover, the method of calcined synthesis with the precursor is advantageous, and more useful for engineering applications.ZrW₂O₈/Cu composites was obtained by exothermic reaction of Al、CuO and ZrW₂O₈. The results by XRD、SEM、EPS and thermal-expansion test indicated that the microstructure by this method was compacted and formed spatial grid structure of Cu. The thermal expansion of this material was performance zero inflation from 30℃to 60℃, and the coefficient was 4.2×10-6/℃from 60℃to 300℃. This material shows very excellent thermal expansion characteristics.ZrV₂O₇/Al was compounded by two different methods: one was pressureless sintering by the powder of ZrV₂O₇ and Al, and another was the precursor of ZrV₂O₇ coated Al powder. The result by XRD、SEM、EPS and thermal-expansion test indicated that the ZrV₂O₇/Al compositeby the precursor coated Al had the good contact surface between Al and ZrV2O7, and the purity of ZrV2O7 was high. The thermal expansion coefficient is 18.5×10-6/℃from 10℃to 120℃. And the thermal expansion coefficient is 4.04×10-6/℃from 120℃to 400℃. From 400℃to 500℃the thermal expansion coefficient is 7.3×10-6/℃. This material displayed normal thermal expansion, but compared Al remarkably dropped. Based the foundation, the gradient material of ZrV2O7/Al was achieved by the method of powder metallurgy. This material had the good microstructure and fine heat-resistant performance.更多还原