Abstract

Due to the high exothermic characteristic of NiAl during the reaction synthesis process from Ni–Al elemental powders, the NiAl intermetallic melts frequently, and the specimens are difficult to maintain their original shape, which leads to the inhomogeneity of the pore size and morphology. To tackle this problem, porous NiAl intermetallic monolith with controllable shape and pore structure was prepared through thermal explosion (TE) using NaCl as space holder. The TE behavior was recorded, and the effect of the volume fraction of NaCl on the phase composition, macroscopic feature, pore morphology and open porosity were investigated. The results showed that NiAl was the main phase in the products, and the specimen was free from cracking or deforming when NaCl content reached 30 vol%. The interconnected channel and pore windows were formed, and the open porosity was improved greatly to 63% by adding 50 vol% NaCl. The leachable space holder route provides a simple way to control the shape, pore structure and open porosity of the synthesized porous NiAl intermetallic.

Graphic Abstract

The use of NaCl as space holder reduced the combustion temperature of NiAl porous intermetallic compounds and kept the macroscopic shape intact.

中文翻译：

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太空架快速热爆炸制备形状和孔结构可控的多孔NiAl金属间化合物

摘要

由于镍铝元素粉末在反应合成过程中镍铝的放热特性高，因此镍铝金属间化合物经常熔化，并且试样难以保持其原始形状，从而导致孔径和形貌不均匀。为了解决这个问题，通过使用NaCl作为空间保持器的热爆炸（TE）制备了形状和孔结构可控的多孔NiAl金属间整体。记录TE的行为，并研究NaCl的体积分数对相组成，宏观特征，孔形态和开孔率的影响。结果表明，NiAl是产品的主要相，当NaCl含量达到30 vol％时，试样无裂纹或变形。相互连接的通道和孔窗口形成了，通过添加50％（体积）的NaCl，开孔率大大提高到63％。可浸出的空间保持器路线提供了一种简单的方法来控制合成的多孔NiAl金属间化合物的形状，孔结构和开孔率。

图形摘要

使用NaCl作为空间保持剂可降低NiAl多孔金属间化合物的燃烧温度，并保持宏观形状不变。