Spark plasma sintering of polycrystalline La0.6Ce0.3Pr0.1B6-ZrB2< /sub> composites

摘要

This paper has studied the densification, microstructure, and properties of polycrystalline La0.6Ce0.3Pr0.1B6-ZrB2 composites prepared by spark plasma sintering (SPS). The highest relative density of 98.7% is obtained at the SPS condition of axial mechanical pressure 50 MPa, sintering temperature 1900 degrees C and holding time 5 min. The Vickers hardness decreases linearly from the maximum value of 21.49 GPa to the value of 8.24 GPa with the tested temperature increased from room temperature to 1000 degrees C. The effects of crack deflection and bridging have resulted in the fracture toughness of 4.56 MPa m(1/2) of dense polycrystalline La0.6Ce0.3Pr0.1B6-ZrB2 composite. The J(1kV) of 7.02 A/cm(2) obtained at 1600 degrees C, the work function of 2.743 eV determined by ultraviolet photoelectron spectroscopy, and the good oxidation resistance below 1100 degrees C in air have revealed that the dense polycrystalline La0.6Ce0.3Pr0.1B6-ZrB2 composite has a good potential to be a promising hot cathode material.

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