立方ZrW_2O_8类型化合物是一类在很宽的温度范围内(0.3-1050K)具有优良的各向同性热收缩性质的化合物。合成立方ZrW_2O_8类型固溶体Zr_(1-x)A_xW_(2-y)Mo_yO_(8-z)并对其性质和结构进行研究，不仅可以深入地认识物质的微观结构与性质的规律性变化之间的关系，而且可以拓宽其应用领域使其具有更广阔的应用前景。本论文用高温固相法合成了系列固溶体ZrW_(2-y)Mo_yO_8 (y = 0.06 - 0.88)和未见报道的固溶体Zr_(1-x)A_xW_2O_(8-z) (A = Al~3+, Mn~2+)；确定了固溶体Zr_(1-x)Al_xW_2O_(8-x/2)的固溶度为3.3mol％。用酸蒸汽水热法合成了固溶体ZrW_2O_7(OH_(1-x)Cl_x)_2•2H_2O (x = 0.016, 0.025)和Zr_0.95Sn_0.05W_2O_8。对固溶体ZrW_(2-y)Mo_yO_8 (y = 0.06 - 0.88)和Zr_(1-x)Al_xW_2O_(8-x/2)的结构与性质的关系首次进行了深入地研究并取得了以下规律性认识:(1) 提出了“两套共轭亚晶格”的初始晶体结构模型。利用中子粉末衍射数据，成功地精修了固溶体ZrW_(2-y)Mo_yO_8 (y = 0.06 - 0.88)的平均晶体结构，得到了平均结构参数如：原子分数坐标，原子占有率，原子位移参数，键长，键角等。精修结果表明：固溶体的晶胞参数和平均结构参数随溶质浓度的变化是晶胞取向有序度函数调制的结果。(2) 根据有序固溶体alpha- ZrW_(2-y)Mo_yO_8和Zr_(1-x)A_xW_2O_(8-x/2)的有序-无序相变温度与组成的线性相关性以及晶胞取向有序度参数与组成的关系，在平均场理论Bragg - Williams近似方程的基础上建立了有序度参数与约化温度的实验方程。利用此方程，可以方便地得到有序固溶体alpha- ZrW_(2-y)Mo_yO_8和Zr_(1-x)A_xW_2O_(8-x/2)在不同温度下或不同组分时的晶体有序度参数。(3) 在系列固溶体Zr_(1-x)A_xWMoO_(8-x/2)和Zr_(1-x)A_xW_2O_(8-x/2)的弹性常数的基础上，总结了这两种类型固溶体的固溶度与晶格畸变(Vegard’s斜率Sv)之间的关系：固溶体Zr_(1-x)A_xWMoO_(8-x/2)的固溶度符合通常的晶格弹性能量阈值控制机理，晶格畸变Sv和固溶度S两者呈反比关系；有序固溶体alpha- Zr_(1-x)A_xW_2O_(8-x/2)的固溶度S表现出正比于Sv的反常的规律，因此我们提出了有序固溶体alpha- Zr_(1-x)A_xW_2O_(8-x/2)的固溶度是由有序度调整的晶格弹性能量阈值控制的机理。此外还建立了固溶体Zr_(1-x)A_xW_2O_(8-x/2)的晶体有序度(eta)与取代和被取代离子的半径差(delta-r)之间的线性关系。

Cubic ZrW_2O_8 has received considerable attention in the past several years because of its isotropic negative thermal expansion over a wide temperature range (0.3-1050K). This makes the investigation of structurally related phases Zr_(1-x)A_xW_(2-y)Mo_yO_(8-x/2) solid solutions an attractive goal.In this paper, ZrW_(2-y)Mo_yO_8 (y = 0.06 - 0.88) and unreported Zr_(1-x)A_xW_2O_(8-z) (A = Al~3+, Mn~2+) solid solutions have been synthesized by solid-state reaction, and the limited solubility of Zr_(1-x)Al_xW_2O_(8-z) was determined to be 3.3mol%. The solid solutions of ZrW_2O_7(OH_(1-x)Cl_x)_2•2H_2O(x = 0.016, 0.025) and Zr_0.95Sn_0.05W_2O_8 were synthesized by ASH method. The relationship between structures and properties of ZrW_(2-y)Mo_yO_8 and Zr_(1-x)Al_xW_2O_(8-x/2) solid solutions was first investigated and some rules were obtained as followed:(1) The initial structure model of “two sets of conjugated sublattice” in the crystal was proposed to refine the solid solution structures. The average crystal structures of ZrW_(2-y)Mo_yO_8 (y = 0.06 - 0.88) were successfully refined based on the neutron powder diffraction data，and the average structure parameters such as atomic coordinates, atiomic occupancy, ADP, bond lengths and angles were obtained. The refined results indicated that structure parameters including lattice parameters, bond lengths and bond angles were dependent of the unit cell orientation order degree. (2) According to the relationship between order – disorder phase transition temperature and solute concentration, together with that between order degree parameter (eta) and solute concentration of ZrW_(2-y)Mo_yO_8 and Zr_(1-x)Al_xW_2O_(8-x/2), the experimental function was obtained based on the Bragg – Williams approximate equation in the average field theory. Using this function, it was easy to calculate the order degree parameters of ZrW_(2-y)Mo_yO_8 and Zr_(1-x)Al_xW_2O_(8-x/2) in different temperatures or different solute concentrations, respectively. (3) Based on the elastic constants of series solid solutions Zr_(1-x)A_xWMoO_(8-x/2) and Zr_(1-x)A_xW_2O_(8-x/2), the relationship between limited solubility and crystal deformation (Sv) was concluded. The limited solubility (S) of Zr_(1-x)A_xWMoO_(8-x/2) was governed by the crystal elastic energy threshold. It was agreed with strained lattice mechanism. In order to explain the abnormal relationship between S and Sv of alpha- Zr_(1-x)A_xW_2O_(8-x/2), we introduced a hypothesis of moldulated elastic energy threshold by crystal order degree to govern S of alpha- Zr_(1-x)A_xW_2O_(8-x/2). In addition, the linear relationship between eta and delta-r (radial difference between substitution and host cations) of Zr_(1-x)A_xW_2O_(8-x/2) was found.