Composition and lattice parameters of a new aluminium-rich borocarbide
Composition and lattice parameters of a new aluminium-rich borocarbide
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DOI：
10.1007/bf00728915
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
J. Viala;G. Gonzales;J. Bouix
中科院分区：
文献类型：
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作者：
J. Viala;G. Gonzales;J. Bouix
用碳化硼颗粒或碳化硼包覆的硼纤维增强铝基基体，可以制备高强、低重量的复合材料或陶瓷[1-3]。在前一种情况下，碳化硼（B4C）是强化剂，而在后一种情况下，B4C涂层的作用是保护纤维在加工或使用复合材料时免受铝的严重攻击。最近，我们实验室的一个试验工厂生产了b4c涂层碳纤维[4,5]。目前正在进行一项一般性研究，目的是利用这些处理过的纤维制造铝基复合材料。然而，这类材料的开发和性能的提高需要对金属-碳化物界面化学的透彻理解，首先是对A1-BC体系中可能通过化学反应形成的相的详细描述。在对B4C-A1陶瓷加工的一般性研究中，Halverson等人观察到，在800 - 1400℃之间的每一种温度下，都会形成一种新的三元化合物，他们称之为X相。Sarikaya等人（[6]）尝试用电子衍射和能量损失谱来表征该相：作者提出了晶格参数为a 0= 0.3520 nm和Co= 0.5820 nm的六方对称结构，化学式为A14BC。本文报道了一种由元素直接合成的富铝硼碳化物的组成和晶格参数，并讨论了该化合物与上述x相之间的可能关系。铝（纯度99.8 wt%，晶粒尺寸d< 50 txm, Alfa Ventron）、硼（纯度99.4 wt%, d< 250/xm, Alfa Ventron）和碳（光谱级，d< 25/xm, Le Carbone Lorraine）的商业粉末在钢砂浆中以原子比AI: B: C= 80混合成球。10:10，在272兆帕下冷压成小棒材（尺寸4mmx6mmx30mm，重量约2g）。这些棒被放置在一个氧化铝船和加热160小时在一个封闭的硅管1273 K在常压净化氩。在此条件下，失重率< 5%。风冷后的样品用x射线粉末衍射（XRD）进行表征，使用标准的飞利浦设备：PW1720发生器，PW1390通道控制单元和PW1050/25两圆测角仪，配备步进扫描电机
High-strength and low-weight composite materials or cermets have been prepared by reinforcing an aluminium-base matrix with boron carbide particles or with boron carbide-coated boron fibres [1-3]. In the former case boron carbide (B4C) is the strengthening agent, whereas in the latter the role of B4C coating is to protect the fibres against a too severe attack by aluminium during processing or use of the composites. Recently B4C-coated carbon fibres have been produced on a pilot plant in our laboratory [4, 5]. A general study is now in progress with the aim of employing these treated fibres for the manufacture of aluminium-base matrix composites. The development of such materials and improvement of their performances require, however, a thorough understanding of the metal-carbide interface chemistry and, primarily, a detailed description of the phases likely to be formed by chemical reaction in the A1-BC system. In a general study on the processing of B4C-A1 cermets, Halverson et al. observed the formation of a new ternary compound, which they called phase X, at every temperature between 800 and 1400 C [1]. Attempts were made by Sarikaya et al.[6] to characterize that phase by electron diffraction and energy-loss spectroscopy: those authors proposed a hexagonal symmetry with the lattice parameters a 0= 0.3520 nm and Co= 0.5820 nm and the chemical formula A14BC. This letter reports the composition and lattice parameters of an aluminium-rich borocarbide that was prepared by direct synthesis from the elements and discusses the possible relationship between this compound and the foregoing phase X.Commercial powders of aluminium (purity 99.8 wt%, grain size d< 50 txm, Alfa Ventron), boron (99.4 wt%, d< 250/xm, Alfa Ventron) and carbon (spectrographic grade, d< 25/xm, Le Carbone Lorraine) were ball-mixed in a steel mortar at the atomic ratio AI: B: C= 80: 10: 10 and cold-pressed under 272 MPa into small rods (dimensions 4mmx6mmx30mm and weight about 2g). These rods were placed on an alumina boat and heated for 160 h at 1273 K in a closed silica tube under atmospheric-pressure purified argon. Under these conditions the weight losses were< 5%. After air-cooling the resultant samples were characterized by X-ray powder diffraction (XRD), using standard Philips equipment: a PW1720 generator, PW1390 channel-control unit and PW1050/25 two-circle goniometer supplied with a step-scanning motor