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首页> 外文期刊>Combustion Science and Technology >Effect of Purity, Surface Modification and Iron Coating on Ignition and Combustion of Boron in Air
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Effect of Purity, Surface Modification and Iron Coating on Ignition and Combustion of Boron in Air

机译：纯度，表面改性和铁涂对空气中硼的点火和燃烧的影响

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Combustion characteristics of boron powders with varying purity, surface treatment and iron dopant loadings were investigated. Particles were ignited by a CO2 laser and burned in air. Commercial 95% and 99% pure boron powders were used as the starting materials; the former powder was also washed with acetonitrile to reduce the inhibiting oxide layer. All powders were coated with iron by thermal decomposition of iron pentacarbonyl. Optical emission of single burning particles was captured in order to determine combustion temperatures and burn times as a function of particle size. All materials ignited at approximately the same CO2 laser beam energy. For all materials, two-stage combustion patterns were detected for longer emission pulses produced by particles burning in air, which became difficult to resolve for shorter burn times. It was observed that higher purity boron particles burn faster. A reduction in the natural oxide layer thickness achieved by acetonitrile wash did not appreciably change the burn time of boron particles. However, it did lead to a brighter emission during second stage combustion, to oscillatory emission patterns, and to formation of nitride caps on the surface of quenched boron particles. Coating boron with iron was effective for commercial 95% pure boron. It was less effective for washed boron and even less effective for boron of higher purity. Boron coated with iron burned faster than un-coated boron; the effect appeared to scale with the amount of iron present. Additionally, boron coated with iron burned at a higher temperature than the un-coated powders. The increase in the burn rate and temperature caused by the iron coating are consistent with the proposed reaction mechanism, in which iron serves as a shuttle catalyst that is oxidized by external oxygen and then reduced by boron.
机译：研究了具有不同纯度，表面处理和铁掺杂剂载荷的硼粉末的燃烧特性。通过CO 2激光点燃颗粒并在空气中燃烧。使用95％和99％纯硼粉作为起始材料;用乙腈洗涤前粉末以减少抑制氧化物层。通过铁戊羰基的热分解涂覆所有粉末。捕获单一燃烧颗粒的光发射以确定燃烧温度和燃烧时间作为粒度的函数。所有材料在大致相同的CO2激光束能量下点燃。对于所有材料，检测到通过在空气中燃烧的颗粒产生的粒子产生的较长排放脉冲的两级燃烧模式，这变得难以解决较短的燃烧时间。观察到较高纯度硼颗粒燃烧得更快。通过乙腈洗涤所获得的天然氧化物层厚度的降低未明显改变硼颗粒的燃烧时间。然而，它确实在第二阶段燃烧期间导致发射较大，振荡发射图案以及在淬火硼颗粒表面上形成氮化物盖。用铁涂层硼对于商业95％纯硼有效。对于洗涤的硼而言，对纯度较高的硼甚至更少有效。硼涂有铁燃烧得比未涂覆的硼更快;效果似乎与存在的铁量缩放。另外，涂有铁的铁在比未涂覆的粉末更高的温度下燃烧。由铁涂层引起的燃烧速率和温度的增加与所提出的反应机制一致，其中铁用作通过外氧氧化的梭催化剂，然后通过硼减少。

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