低压固相烧结制备高致密度LaB_6多晶体

Preparation of High-density LaB_6 Polycrystalline by Low-pressure Solid-state Sintering

以平均粒径为20μm的自制高纯LaB6粉末为原料,采用低压固相烧结工艺制备高致密度LaB6多晶体,考察了压制时间、压力与致密度的关系,并探讨了致密度对材料性能的影响。实验结果表明:一次热压制备内径Φ30 mm高致密度LaB6多晶体工艺参数为:烧结温度2 000℃、热压压力5 MPa、热压时间2 h。在此条件下,产品相对致密度可达到95.9%,抗弯强度为154 MPa,洛氏硬度为87,空心阴极发射电流大于10 A/cm2。该工艺与其它制备工艺相比,设备要求低,产品相对致密度高,具有广阔的工业应用前景。

High-density LaB6 polycrystalline bulks were fabricated by low-pressure solid-state sintering using self- prepared LaB6 powder with an average particle size of 20 μm. An investigation was made on the relationship between the pressing time, pressure and density. The influence of density on material properties was studied as well. The results show that the process parameters for once hot pressing of high-density LaB6 polycrystalline of 030 mm are as follows ： sintering temperature of 2 000 ℃, sintering pressure of 5 MPa and holding time of 2 h. Under such conditions, the relative density, bend strength, Rockwell hardness and hollow cathode emission density of the LaB6 polycrystalline are 95.9%, 154 MPa, 87 and more than 10 A/cm2, respectively. Compared with other preparation processes, this process with lower requirements for the equipment can bring products with higher relative density, presenting a broad prospect for industrial applications.