采用大气等离子喷涂，在不同喷涂距离下制备了碳化硼涂层，研究了喷涂距离对碳化硼涂层的显微结构、相组成和电导率的影响．用EDS和XPS分析了涂层的相组成；扫描电镜观察涂层的显微结构；标准四探针法测量涂层的电导率．结果表明，喷涂距离不仅会影响碳化硼涂层的显微结构，而且会改变碳化硼涂层的相组成；等离子喷涂碳化硼涂层的表面电导率随温度的增加而增加，表现出明显的半导体特性；涂层表面电导率同相组成和显微结构密切相关，涂层中B2O3相含量越高，气孔率越大，则涂层的电导率越低．
Boron carbide coatings were deposited under atmospheric pressure by plasma spray at different spraying distance. Their microstructure
and phase composition were studied through EPMA, EDS and XPS. Their dc conductivity was measured by standard four-probe. The results show that
the suitable spraying distance causes dense B4C coating; the longer the spraying distance, the serious oxidation of B4C powder is,
the spraying distance may severely affect the phase composition. The plasma spray boron carbide coatings possess semiconductor properies. The
conductivity increases with temperature. The phase composition and B/C ratio determined by the spraying distance, can affect the conductivity of boron carbide coating.
参考文献
| [1] | Samsonov G V, Vinitskii I M. Handbook of Refractory Compounds., IFI / Plenum. NY, 1980. 414--415 2 Milkins M L. In Boron and Refractory Borides, Edited by B.L.Matkovich. Springer-Verlag, NY, 1977. 633--634 3 Reinmuth K, Lipp A, Knoch H, et al. J. Nucl. Mater., 1984, 175: 124--129 4 Kanno Y. Yogyo Kyokaishi. 1986, 94 (4): 449--451 5 Bouchacourt M, Thevenot F. J. Mater. Sci., 1986, 20: 1237--1247 6 Wood C, Emin D. Phys Rev, B, 1984, 29: 4582--4586 7 Bray B, et al., J. Less-common Metals 1979, 67: 327--343 |
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