Abstract
Abstract La0.6Ce0.3Pr0.1B6-ZrB2 directionally solidified eutectic (DSE) with the [100] orientation of the La0.6Ce0.3Pr0.1B6 matrix is firstly fabricated via the optical floating zone technique using LaB6, CeB6, PrB6 and ZrB2 powders as raw materials. The microstructure, mechanical and thermionic emission properties of the as-grown La0.6Ce0.3Pr0.1B6-ZrB2 DSE were systematically investigated. The ZrB2 fibers, whose average diameter is 0.8–1.2 μm, are embedded in the [100] La0.6Ce0.3Pr0.1B6 matrix and uniformly distributed. The Vickers hardness does not vary apparently between the transverse and longitudinal sections of La0.6Ce0.3Pr0.1B6-ZrB2, while the fracture toughness is of highly anisotropy. The fracture toughness of 5.71 MPa m1/2 on the longitudinal section, flexural strength of 826.50 MPa and thermionic emission current density of 84.96 A/cm2, which are all higher than that of LaB6 or LaB6-ZrB2, indicate that the La0.6Ce0.3Pr0.1B6-ZrB2 DSE grown here will have great application prospects as a candidate for high-performance thermionic emitters.
Published Version
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