These silicon carbide nanopar- ticles used with magnesium casting alloys have an average particle size of about 50 nanometers.
在镁合金中使用的硅碳纳米 颗粒尺寸基本小于50纳米。
ing the nanoparticles apart and uniformly dispersed throughout the metal during solidification. “For the past six years,
we’ve been working on the fundamentals of how to get the nanoparticles to disperse in the metal,” Li said. “Ultra- sonic technology is one of the more inexpensive ways.”
Lab to Line
Early nanotechnology testing was performed with batches of 5 to 10 lbs. of material at a time. In order to use the process in a production metalcasting facility, more work is required. “How do we scale up to reasonable production batches
of material, which at Eck is 500 lbs.?” Weiss said. “Te whole jist of the [research funding] is to be able to scale it up to make real components. Te plan is to take it from a laboratory curiosity into something with which we can make metal castings.” To scale up the work for production, tools to disperse
nanoparticles on a larger scale have to be created. Cur- rent tools used to do the same thing in polymers cannot withstand the high temperatures of molten aluminum and magnesium. Te time it takes to add the particles to the melt is also unwieldy. According to Weiss, the researchers are in the midst
of scaling up to 50 to 60 lbs. of material at a time. Once production is consistent at that size, the group will try to scale up further. However, even at 60 lbs., Weiss said early applications will be able to use the technology. “We have cast some internal samples for continued
development work for material qualification purposes,” Weiss said. “We’re looking for consistent, proper distribution of nanoparticles.” Behind the scenes, research- ers in the university and industry program have devel- oped techniques to model the incorporation of nanoparticles into the melt and improve the quality and consistency in load- ing the particles.
Shown are nanoparticles dispersed in a cast magnesium test ingot.
实验线
早期每次纳米材料试 验只有5-10磅重。要在 铸造厂应用，还需要做 大量工作。“怎样才能 使我们在Eck公司到底 每次500磅的规模生产 呢？”Weiss说，“【研 究基金】的主要目标是生 产真正的复合材料，我们
的计划是将纳米技术从实验室研究转化成工业生产。” 要想将实验研究转化成生产，需要制造能分散更多纳 米颗粒的机器。现有处理高分子材料的机器不能承受镁 铝金属熔化时的高温。同时需要添加颗粒的次数太多， 所以显得太过笨重。 根据Weiss的说法，现在的研究成果提高到了每次 50-60磅重。要在生产上达到稳定水平，研究组需要想 方设法提高一个层次。Weiss说即使达到60磅的水平， 也能够进行初步应用了。
“我们已经铸造出了一些内部样品用于材料合格检 验，以便继续开发，”Weiss说。“我们在寻找稳定的 均匀分布的纳米颗粒分离方法。”企业和学校的研究人 员已经开发了模拟纳米颗粒的如何添加到熔体和如何提 高纳米颗粒添加的质量和连续性控制的技术。 不同纳米颗粒与不同的合金结合更好。纳米研究团队 已经成功将纳米颗粒覆盖在陶瓷上用来使它们更好的与 金属结合。
“我们也需要特殊的纳米 颗粒，”李教授说，“现在大
部分颗粒都使用在半导体上， 但是那不适用于我们金属行 业。”
然而主要的问题在于使金 属铸造厂商以他们能支付的方
镁锭中纳米颗粒的分散。 Fall 2011
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