硼含量对碳硼化合物结构、力学影响行为研究

利用低压化学气相沉积技术, 以BCl₃-C₃H₆-H₂为反应气体制备了不同掺硼量的热解碳薄膜B_xC_1-x(x=0.05, 0.10, 0.16, 0.30, 0.50), 并研究了硼含量对B_xC_1-x微观结构及力学性能的影响。B_0.1C_0.9展现了高度结晶的类石墨结构, 其中大部分B取代石墨层中的C。随着B含量上升, B主要形成B-C键, B_xC_1-x结构向无定型转变。纳米压痕测试结果显示, B_0.1C_0.9的弹性模量和硬度较低, 载荷位移曲线显示其力学变形接近弹性变形, 随着B含量增加, 碳化硼生成量增加, 其弹性模量和硬度显著提升, 载荷位移曲线表现出典型的脆性材料力学行为。

Boron Content on Microstructure and Mechanical Properties of Amorphous Boron Carbide by Chemical Vapor Deposition

Boron carbide coatings B_xC_1-x (x=0.05, 0.10, 0.16, 0.30, 0.50) were prepared by low pressure chemical vapor deposition technique from BCl₃-C₃H₆-H₂ precursor mixtures. The effects of boron content on the microstructure and mechanical behaviors of the B_xC_1-x were investigated. The B_0.1C_0.9 coating displayed a graphite-like structure of high crystallinity where a large fraction of boron atoms exists as atomic substituent in the carbon layers. As boron content increased, the structure tended to be amorphous, because of the formation of increasingly numbers of B-C bonds. The B_0.1C_0.9 coating showed a low hardness and elastic modulus, and its mechanical behavior was close to that of an elastic soft film. The H and E of B_xC_1-x coatings were significantly enhanced at high boron content level, because of the formation of increasing amounts boron carbide in them.