Understanding Physical Property Variation in Vapor-Grown Carbon Fibers

这项小型企业创新研究第一阶段项目旨在识别并消除一种名为蒸汽生长碳纤维（VGCF）的新型石墨纤维中缺陷形成的来源。VGCF具有等同于或大大超过其他类型的碳纤维和金属的工程性能。此外，VGCF可以通过简单、快速和廉价的化学气相沉积（CVD）工艺生产，从而有可能大大降低高性能碳纤维增强材料的成本。然而，VGCF的实用性目前受到批量生产模式的限制，批量生产模式会在批次内以及批次之间产生很大的物理特性变化。因此，光纤的可预测性不足，无法用于关键的工程应用。拟议的研究工作将寻求确定纤维质量变化的来源，并通过改进CVD工艺来消除变化。具体地说，这项工作将调查纤维性能变化与纤维的特定形态特征（称为圆纹）之间的关系，然后确定那些过程变量，这些过程变量的仔细控制将最好地缩小纤维性能值的范围。优化这些变量和开发更好地控制它们的技术，特别是在大批量生产期间，将是相关第二阶段工作的重点。

This Small Business Innovation Research Phase I project seeks to identify and eliminate the sources of defect formation in a novel graphitic fiber called Vapor Grown Carbon Fiber (VGCF). VGCF possesses engineering properties that equal or greatly exceed other types of carbon fiber, as well as metals. Additionally, VGCF can be produced in a simple, rapid and inexpensive chemical vapor deposition (CVD) process, thus holding potential to greatly reduce the cost of high performance carbon fiber reinforcements. However, the usefulness of VGCF is currently limited by batch-mode production which yields a large variation in physical properties both within the batch, as well as between batches. Consequently, the fibers are not sufficiently predictable to commit to critical engineering applications. The proposed research effort will seek to identify the source of variations in fiber quality, and to eliminate the variations through refinements in the CVD process. Specifically, this effort will investigate the relationship between variation in fiber properties and the occurrence of a particular morphological feature of the fibers called crenulations, and then determine those process variables whose careful control will best narrow the range of values of the fiber properties. Optimization of these variables and development of techniques to better control them, especially during higher volume production, will be the intended focus of the associated Phase II effort.