中文摘要：

在空气和真空条件下对α-Fe_2O_3粉末进行了从室温到1 000℃的高温原位X射线衍射研究,分别修正了空气和真空条件下赤铁矿在27-1 000℃范围内的晶胞参数,从而得到了晶胞参数随温度变化的关系和赤铁矿在空气和真空条件下的热膨胀系数,并得出了热膨胀系数与温度的关系,即赤铁矿的热膨胀系数不随温度变化。赤铁矿在空气气氛下的热膨胀系数为αa=9.603 16×10^-6/℃,αc=6.647 67×10^-6/℃,β=2.606 33/℃;真空气氛下的热膨胀系数为αa=9.006 79×10^-6/℃,αc=6.891 23×10^-6/℃,β=2.511 51/℃。

英文摘要：

In situ X-ray diffraction patterns of the powder hematite polymorphs were recorded in a temperature range from room temperature（ RT） to 1 000℃ in static air and vacuum. Lattice parameters for hematite（ RT -1 000℃） in static air and vacuum were refined. The variations of lattice parameters of hematite with temperature were therefore well described. Linear（ α） and volume（ β） thermal expansion coefficients of hematite（ RT -1 000℃） were calculated. The change laws of α and β with temperature for hematite in static air and vacuum were summarized. It is shown that linear（ α） and volume（ β） thermal expansion coefficients of hematite（ RT - 1 000℃）are constant with increasing temperature. The thermal expansion coefficients for hematite are αa= 9. 603 16 ×10^-6/℃, αc= 6. 647 67 × 10^-6/℃, β = 2. 606 33/℃ in static air and αa= 9. 006 79 × 10^-6/℃, αc= 6. 891 23× 10^-6/℃, and β = 2. 511 51/℃ in vacuum.