Abstract—

BiFe₂(PO₄)₃ and Bi_1–xSb_хCr₂(PO₄)₃ (0 < x < 1) solid solutions, isostructural with α‑CaMg₂(SO₄)₃ (sp. gr. P6₃/m), have been prepared via boiling down a salt solution, followed by heat treatment, and characterized by X-ray powder diffraction and electron probe X-ray microanalysis. Using variable temperature X-ray diffraction, we have determined thermal expansion parameters of the phosphates in the range from 173 to 473 K. As the temperature is varied, the phosphates expand anisotropically, without polymorphic transitions. BiFe₂(PO₄)₃ and the Bi_1–xSb_хCr₂(PO₄)₃ solid solutions are low-expansion materials, with average linear thermal expansion coefficients α_av below 2 × 10^–6 K^–1.

中文翻译：

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一类新磷酸盐的合成和热膨胀——α-CaMg2(SO4)3 的类似物

摘要——

BiFe ₂ (PO ₄ ) ₃和 Bi _{1– x} Sb _х Cr ₂ (PO ₄ ) ₃ (0 < x < 1) 固溶体，与 α-CaMg ₂ (SO ₄ ) ₃ (sp. gr. P 6 ₃ )同构/米)，通过煮沸盐溶液，然后热处理制备，并通过 X 射线粉末衍射和电子探针 X 射线微量分析进行表征。使用变温 X 射线衍射，我们确定了磷酸盐在 173 到 473 K 范围内的热膨胀参数。随着温度的变化，磷酸盐各向异性膨胀，没有多晶型转变。BiFe ₂ (PO ₄ ) ₃和Bi _{1– x} Sb _х Cr ₂ (PO ₄ ) ₃固溶体是低膨胀材料，平均线性热膨胀系数α _av低于2 × 10 ^–6 K^–1 .