机械合金化法制备超细Al-Ti粉及其反应活性研究

Preparation of Ultrafine Al-Ti Powders by Mechanical Alloying and Its Reactivity

采用机械球磨法,通过控制球磨时间和硬脂酸添加量,制备了具有纳米晶粒度的Al-Ti合金粉Al0.9Ti0.1和Al0.7Ti0.3,用该样品与Fe2O3混合制备Al-Ti/Fe2O3复合铝热剂样品。结构表征表明,机械合金化后得到的Al-Ti粉程粒状,其表面存在1-10μm的超细微观结构,Al、Ti之间相互扩散,形成薄片状的Al-Ti二元复合结构;且元素含量与合金粉的原配比相一致。热分析结果表明Al-Ti合金粉就有很高的反应活性。在空气中,在熔化前发生了明显的氧化还原反应,这种固-气相反应在原料Al粉的DSC图谱中却没有出现,且Al Ti-O2体系的高温反应放热峰较Al-O2体系提前。此外对Al-Ti与Fe2O3铝热体系,其在合金融化前也发生了显著的固-固反应,并且Al粉融化前出现了明显的固-固相反应反应,这表明由Al-Ti合金组成的铝热剂具有优异的点火性能。

Al-Ti alloy powders Al0.9 Ti0.1 and Al0.7 Ti0.3 with nano-grain size were prepared by controlling the milling time and the addition amount of stearic acid by mechanical ball milling method. The samples were prepared by mixing with Fe2 O3 Al-Ti/Fe2 O3 composite aluminum heat sample. The structure of the Al-Ti powder was characterized by the mechanical properties of the Al-Ti powder, and the surface of the Al-Ti powder was in the form of an ultra-fine structure of 1 to 10 μm, and Al and Ti were diffused to form a flaky Al-Ti binary composite structure. The elemental content is consistent with the original ratio of the alloy powder. The results of thermal analysis show that Al-Ti alloy powder has a high reactivity. In the air, a significant redox reaction occurred before melting, and this solid-gas phase reaction did not occur in the DSC pattern of the raw Al powder, and the high temperature reaction exothermic peak of the Al Ti-O2 system was earlier than that of the Al-O2 system. In addition, the Al-Ti and Fe2 O3 aluminum thermal systems, which had a significant solid-solid reaction before the alloy was melted, and a significant solid-solid reaction occurred before the Al powder was melted, indicating that the Al-Ti alloy of the aluminum heat agent has excellent ignition performance.