【摘要】 采用燃烧法在较低温度下成功合成了各向同性的负热膨胀材料ZrW2O8粉体。用X射线衍射、扫描电镜、红外光谱综合分析和研究了反应过程中炉温、硼酸和尿素含量、W6+与Zr4+的摩尔比对合成ZrW2O8纯度的影响。结果表明:燃烧法可以合成高纯度、粒径为0.5μm的ZrW2O8粉体。燃烧法合成高纯ZrW2O8的最佳条件是:炉温为500℃,硼酸的摩尔分数为10%,(NH2)2CO与(NH4)5H5[H2(WO4)6]·H2O+ZrOCl2·8H2O的质量比为2:1,(NH4)5H5[H2(WO4)6]·H2O与ZrOCl2·8H2O的摩尔比为1:3.2。所合成的ZrW2O8在50～700℃之间的线膨胀系数α=-5.08×10-6/℃,其线膨胀系数与温度的关系符合方程dL/L0=-1.4×10-2-4.5×10-4T(50℃≤T≤700℃)。更多还原

【Abstract】 Isotropic ZrW2O8 powders material with negative thermal expansion were successfully synthesized via a combustion method at low temperature. The effects of the furnace temperature, the H3BO3 and (NH2)2CO content, and the molar ratio of W6+ and Zr4+ on the purity of the synthesized ZrW2O8 powders were investigated by X-ray diffraction, scanning electron microscopy and infrared spectrum. The results show that high purity ZrW2O8 powders with a mean particle size of 0.5 μm, can be obtained by the method under the follo- wing conditions: a furnace temperature of 500 ℃; a H3BO3 molar fraction of 10%; a 2:1 mass ratio of (NH2)2CO and (NH4)5H5[H2(WO4)6]·H2O added to ZrOCl2·8H2O; and a 1:3.2 molar ratio of (NH4)5H5[H2(WO4)6]·H2O and ZrOCl2·8H2O. The linear thermal expansion coefficient of prepared ZrW2O8 material is -5.08×10-6/℃ in the temperature range from 50℃ to 700℃. The equation for the relationship of thermal expansion to the temperature of the material is dL/L0=-1.4×10-2-4.5×10- 4T.更多还原