Atmospheric-Pressure Flame Vapor Deposition of Nanocrystalline Diamonds: Implications for Scalable and Cost-Effective Coatings
Atmospheric-Pressure Flame Vapor Deposition of Nanocrystalline Diamonds: Implications for Scalable and Cost-Effective Coatings
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DOI：
10.1021/acsanm.2c02059
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发表时间：
2022-07-21
影响因子：
5.9
通讯作者：
Cai, Lili
中科院分区：
文献类型：
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作者：
Manjarrez, Adrian;Zhou, Kai;Cai, Lili
纳米晶金刚石（NCD）是众多碳同素异形体中的一种，由于其上级的机械、热和光学性能而引起了许多技术进步的极大关注。然而，它们的合成必须加以改进，以便以低成本获得和广泛应用。在这里，我们报告的大气压火焰气相沉积（FVD）的NCD颗粒和薄膜的合成面积超过27平方厘米，使用甲烷-氢气-空气平面火焰。在大气压下合成是有益的，因为与低压和高压方法的分批合成相比，它可以降低成本并且更省时。此外，丰富的甲烷气体可进一步降低成本并提高可扩展性，同时产生较低的火焰温度以减轻对大量冷却的需求。值得注意的是，FVD方法解锁了金刚石生长的条件，超出了先前考虑的C-H-O相图的金刚石生长区域。作为指导，通过建模的火焰自由基物种，我们实验证明，FVD生长的NCD可以很容易地控制通过调整反应气体的组成，衬底材料，和播种密度。此外，我们发现，除了一个外部的电偏压是有影响的控制的孔隙率和厚度的NCD膜。总的来说，由于成本低，操作简单，不需要真空，这种大气压FVD方法将提供机会，以促进NCD合成在光学，摩擦学，热学和生物医学涂层中的应用的规模扩大。
Nanocrystalline diamonds (NCDs) are one of the many carbon allotropes that have attracted great attention for the advancement of many technologies owing to their superior mechanical, thermal, and optical properties. Yet, their synthesis must be improved for availability at low costs and their widespread application. Here, we report the atmospheric-pressure flame vapor deposition (FVD) synthesis of NCD particles and thin films over an area of more than 27 cm2 using methane-hydrogen-air flat flames. Synthesis at atmospheric pressure is beneficial as it can lower costs and be more time-efficient when compared to the batch-by-batch synthesis of low-pressure and high-pressure processes. Also, the abundance of methane gas available can further lower costs and improve scalability, while generating lower flame temperatures to mitigate the need of extensive cooling. Notably, the FVD method unlocks conditions for diamond growth beyond the previously considered diamond-growth region of the C-H-O phase diagram. By modeling the flame radical species as a guidance, we experimentally demonstrate that the FVD growth of NCDs can be facilely controlled by tuning the reactant gas composition, substrate material, and seeding density. Moreover, we show that the addition of an external electric bias was influential in controlling the porosity and thickness of the NCD films. Overall, with the low cost and simplicity for operation without the need of vacuum, this atmospheric-pressure FVD approach will offer opportunities to facilitate the scaling-up of NCD synthesis for applications in optical, tribological, thermal, and biomedical coatings.