SBIR Phase I: Ultrananocrystalline Diamond as Wear Resistant and Protective Coating for Mechanical Shaft Seal Applications

这个小型企业创新研究（SBIR）第一阶段项目提出了基于一种称为超纳米晶（TM）金刚石的新型材料开发机械轴密封的耐磨和保护涂层。金刚石，因为它的硬度，化学惰性和低摩擦系数是一个明显的候选人涂层机械轴密封。传统的CVD金刚石技术（基于H2/CH 4气体化学）产生微晶（或纳米晶）金刚石，由于大的晶粒尺寸和高的内应力而不适合。基于Ar/CH 4气体化学的新工艺生产出的金刚石具有小粒度（2-5 nm）和约20-30 nm的表面粗糙度，非常适合此类应用。机械轴封几乎在每个行业都有应用。这些密封件的主要功能是确保泵送流体不会逸出系统，并保护流体免受污染。目前，碳化硅（SiC）是这些行业中使用的大多数密封件的首选材料。然而，一些研究表明，由于这种材料的摩擦性能差，几乎20%的能量因摩擦而损失。通过将这些设备中的轴封效率提高两倍，估计可以实现6x 109千瓦时/年的全球节能。

This Small Business Innovation Research (SBIR) Phase I project proposes to develop wear resistant and protective coatings for mechanical shaft seals based on a novel material called Ultrananocrystalline (tm) diamond. Diamond, because of its hardness, chemical inertness and low friction coefficient is an obvious candidate for coating mechanical shaft seals. Conventional CVD diamond technology (based on H2/CH4 gas chemistry), which produces microcrystalline (or nanocrystalline) diamond is not suitable because of large grain sizes and high internal stresses. The new process based on Ar/CH4 gas chemistry produces diamond with small grain sizes (2-5 nm) and a surface roughness of about 20-30 nm which is ideally suited for such applications.Mechanical shaft seals are used in almost every industry. The main functions of these seals are to ensure that the pumping fluid does not escape the system and to protect the fluids from contaminants. Presently, silicon carbide (SiC) is the material of choice for most of the seals used in these industries. However, several studies have shown that due to poor friction properties of this material, almost 20% of the energy is lost due to friction. By improving the efficiency of shaft seals in these devices by just factor of two, it is estimated that a worldwide energy savings of 6x109 Kw-hr/year could be achieved.