GOALI: Investigation of Structure and Properties of Si Doped Boron Carbide

GOALI：硅掺杂碳化硼的结构和性能研究

• 批准号: 0604314
• 负责人: Manish Chhowalla
• 金额: $ 42万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0604314&HistoricalAwards=false
• 关键词: GOALI; Investigation; Structure; Properties; Si

NON-TECHNICAL DESCRIPTION: Boron carbide (nominally B4C) is an important technological material because of its high hardness and low density. These properties make it a material of potential interest for wear resistant coatings as well as security, safety and ballistic applications (i.e. personnel and vehicular armor). Surprisingly, given these properties, it has been found that boron carbide is not particularly good at withstanding high velocity impacts. The aim of the proposed research is to initially thoroughly understand the structure of B4C and then modify it by adding a small amount of silicon in order to enhance its performance at high velocity impacts. The basis of the proposed comes from the fact that we have preliminary results based on calculations that the weak link in B4C can be eliminated by adding 1 - 5% silicon. The successful outcome of this project should lead to the realization of a material that has hardness values only second to those of diamond. Such a material will be useful in wide ranging applications but especially as an armor material against high velocity threats. The project will involve collaboration with several industrial partners who are ceramic armor providers. In addition, the project will involve training of undergraduate female or minority students. We also intend to invite an elementary or high school teacher over the summer in order to translate our research activity from the laboratory to the classroom.TECHNICAL DETAILS: Ab-initio calculations have shown that B4C is unique in that numerous polytypes can co-exist simultaneously due to similar lattice parameters and stability energies. One of these polytypes [B12(CCC)], however, has a very low impact resistance, failing at much lower pressure (~ 7 GPa) compared to other polytypes (40 GPa). Thus, the B12(CCC) polytype is the weak link in B4C which leads to its premature failure at high impact velocities. Calculations have recently revealed that it is possible to eliminate the B12(CCC) polytype from B4C by addition of 1 - 5% Si. The incorporation is possible, without separation in to SiC and B4C, through far-for-equilibrium processing using sputtering or plasma melting. It is anticipate that such a fundamental investigation of Si containing boron carbide will provide insights into how to improve its mechanical properties in order to minimize damage from high-pressure impacts. The project also provides training in latest materials processing and characterization techniques to graduate students.

非技术描述：碳化硼（通常称为 B4C）因其高硬度和低密度而成为一种重要的技术材料。这些特性使其成为耐磨涂层以及安保、安全和防弹应用（即人员和车辆装甲）方面具有潜在吸引力的材料。令人惊讶的是，考虑到这些特性，已经发现碳化硼在承受高速冲击方面并不是特别好。本研究的目的是初步彻底了解 B4C 的结构，然后通过添加少量硅对其进行修改，以增强其在高速冲击下的性能。该提议的基础来自这样一个事实：我们根据计算得出的初步结果表明，通过添加 1 - 5% 的硅可以消除 B4C 中的薄弱环节。该项目的成功结果将导致实现硬度值仅次于金刚石的材料。这种材料将具有广泛的应用，特别是作为抵御高速威胁的装甲材料。该项目将涉及与陶瓷装甲供应商的几个工业合作伙伴的合作。此外，该项目还将涉及对本科女生或少数民族学生的培训。我们还打算在暑假邀请一名小学或高中老师，以便将我们的研究活动从实验室转移到课堂。技术细节：从头计算表明，B4C 的独特之处在于众多多型体可以同时共存由于相似的晶格参数和稳定能。然而，其中一种多型体 [B12(CCC)] 的抗冲击性非常低，与其他多型体 (40 GPa) 相比，在低得多的压力 (~ 7 GPa) 下会失效。因此，B12(CCC) 多型体是 B4C 中的薄弱环节，导致其在高冲击速度下过早失效。最近的计算表明，通过添加 1 - 5% Si，可以从 B4C 中消除 B12(CCC) 多型体。通过使用溅射或等离子熔化的远平衡处理，可以在不分离成SiC和B4C的情况下进行掺入。预计对含硅碳化硼的这种基础研究将为如何提高其机械性能以最大限度地减少高压冲击造成的损坏提供见解。该项目还为研究生提供最新材料加工和表征技术的培训。