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    Tb2TiO5-Dy2TiO5中子吸收材料的显微组织及性能

    Microstructure and Properties of Tb2TiO5-Dy2TiO5 Neutron Absorber Material

    • 摘要: 以Tb4O7粉、Dy2O3粉和TiO2粉为原料,采用高能球磨、冷等静压和高温烧结工艺制备了Tb2TiO5-30%(质量分数) Dy2TiO5中子吸收材料,研究不同球磨时间(0~48 h)下混合粉体的微观结构,不同烧结温度(1 200~1 400℃)与时间(1~96 h)下烧结块体材料的微观结构、热物理性能和耐腐蚀性能。结果表明:混合粉体的晶粒尺寸随球磨时间的延长而减小,球磨12 h后即可获得均匀混合的纳米晶粉体,纳米晶混合粉体在1 300℃烧结96 h获得了具有高致密度正交晶体结构Tb2TiO5-Dy2TiO5块体材料;该块体材料在500℃的热导率和热膨胀系数分别为2.2 W·m-1·K-1和5.8×10-6 K-1,在360℃/18.6 MPa去离子水中的腐蚀速率变化很小,平均腐蚀速率为0.18 mg·dm-2·h-1,该块体材料具有较高的热导率、较低的热膨胀系数以及较好的耐高温水腐蚀性能,是控制棒用中子吸收材料较优的候选材料。

       

      Abstract: Tb2TiO5-30wt%Dy2TiO5 neutron absorber material was prepared by high energy ball milling, cold isostatic pressing and high temperature sintering with Tb4O7 powder, Dy2O3 powder and TiO2 powder as raw materials. The microstructure of the powder mixture at different ball milling time (0-48 h), and the microstructure, thermophysical properties and corrosion resistance of sintered bulks at different sintering temperature (1 200-1 400 ℃) for different times (1-96 h) were studied. The results show that the grain size of powder mixtures decreased with increasing ball milling time, and the homogeneous nanocrystalline powder mixture was obtained by ball milling for 12 h. Tb2TiO5-Dy2TiO5 bulks with high density and orthorhombic structure was obtained after sintering nanocrystalline powder mixture at 1 300 ℃ for 96 h. The thermal conductivity and thermal expansion coefficient at 500 ℃ were 2.2 W·m-1·K-1 and 5.8×10-6 K-1, respectively. The corrosion rate of the bulks in deionized water at 360 ℃/18.6 MPa almost kept a constant and the mean corrosion rate was 0.18 mg·dm-2·h-1. The prepared bulks had high thermal conductivity, low thermal expansion coefficient and good corrosion resistance performance, which was an excellent candidate as neutron absorber materials for control rods.

       

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