Field Application Effects in Rapid Sintering of Activated Powders by a Manufacture Friendly Consolidation Process

通过制造友好的固结工艺快速烧结活化粉末的现场应用效果

• 批准号: 9532072
• 负责人: Joanna Groza
• 金额: $ 25.78万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9532072&HistoricalAwards=false
• 关键词: Field; Application; Effects; Rapid; Sintering

9532072 Groza In the prior NSF funded research, the investigators have demonstrated that metals and ceramics powders can be rapidly consolidated to very high density by applying electric fields as well as pressure in a specified manner. The process is termed "Plasma Activated Sintering." The underlying hypothesis is that electric discharge creates plasma between particles causing local changes on the surface which facilitates the rapid sintering in the subsequent resistant heating under pressure. However, the exact mechanism has not been verified. In the current research, the investigators will use fiber optics to see whether there is indeed plasma between particles. The role of electric field will be studied since the process appears to work on both highly conductive metals (nickel) as well as less conductive ceramics (aluminum oxide). While prior work has suggested atomic level interfacial bonding with clean oxide free grain boundaries in aluminum nitride, what is going on at the particle surface has not yet been understood. The research will also include developing and verifying sintering models under field assisted consolidation. The resultant microstructures will be correlated to the process to develop controls needed to make useful parts from powder materials. Powder consolidation is central to the manufacture of several classes of advanced structural ceramics as well as many powder metal parts used in the industry. Starting from very fine powders is the desired approach to maximize the material properties. However, in processing fine powders, elimination of pores between particles is very difficult without losing the intrinsic advantage of the starting fine particle size. Since pores weaken the parts, any process such as the one described here which can rapidly consolidate the powders offers a new manufacturing avenue. This research will lay the foundation for the necessary large scale equipment needed for the process to be scaled up from the research stage to deve lopment and final commercialization. Several industrial powder processing manufactures have shown interest in this novel process.

9532072 Groza 在之前NSF资助的研究中，研究人员已经证明，通过以特定方式施加电场和压力，金属和陶瓷粉末可以快速固结到非常高的密度。 该过程被称为“等离子体活化烧结”。“基本假设是，放电在颗粒之间产生等离子体，导致表面局部变化，这有助于在随后的压力下电阻加热中快速烧结。 然而，确切的机制尚未得到验证。 在目前的研究中，研究人员将使用光纤来观察粒子之间是否确实存在等离子体。 电场的作用将被研究，因为该过程似乎对高导电金属（镍）以及导电性较低的陶瓷（氧化铝）都起作用。 虽然先前的工作已经提出了氮化铝中原子水平的界面结合与清洁的无氧化物晶界，但颗粒表面发生了什么尚未被理解。研究还将包括开发和验证现场辅助固结下的烧结模型。 由此产生的微观结构将与过程相关联，以开发从粉末材料制造有用部件所需的控制。 粉末固结是制造几类高级结构陶瓷以及工业中使用的许多粉末金属零件的核心。 从非常细的粉末开始是最大限度地提高材料性能的理想方法。然而，在加工细粉末时，在不失去起始细粒度的固有优势的情况下消除颗粒之间的孔隙是非常困难的。 由于孔隙会削弱零件的强度，因此任何可以快速固结粉末的工艺（如本文所述）都提供了一种新的制造途径。 该研究将为该工艺从研究阶段到开发和最终商业化所需的大型设备奠定基础。 一些工业粉末加工制造商已经对这种新方法表现出兴趣。