Tb2TiO5-Dy2TiO5中子吸收材料的显微组织及性能

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。

Microstructure and Properties of Tb2TiO5-Dy2TiO5 Neutron Absorber Material

Tb₂TiO₅-30 wt%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(1200-1400℃)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 1300℃ 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.