Nanocrystalline Thin Films of New Ultra-Hard Borides for Microelectromechanical Systems (MEMS) and Tooling Applications

Iowa State University, Ames IA

Investigators

Abstract

The objective of this grant is to develop a fundamental understanding of synthesizing nanocrystalline thin films of ultra-hard borides with predictability and reproducibility. Ultra-hard borides, recently discovered by the co-Principal Investigator, are the new, second hardest materials on earth with a projected cost of manufacture approximately 10% of the cost of diamond and cubic BN. Research will focus on the development of a novel Ti:Sapphire femtosecond (fs) pulsed laser deposition (PLD) technique for preparing ultra-hard boride thin films on silicon and cemented carbide substrates for Microelectromechanical Systems (MEMS) and hard turning applications respectively. The films will be compared to those deposited by conventional nanosecond (ns) PLD. The research will investigate the laser-boride interactions as a function of pulse width and the interactions of plasma with the surface of substrate that affect the evolution of structure, composition, and growth of films. Nanoindentation and scratch tests will be used for mechanical characterization that includes hardness, Young's modulus, and adherence. Hard coating applications in tools and MEMS will be explored. The research has potential for enormous payoffs. This pioneering work will set the stage and serve as a catalyst for rapid and innovative advances in the new boride materials for numerous tool and hard coating applications including bulk cutting tools, hard and erosion resistant coatings, wear-resistant electrical switch contacts, and conductive thin films for MEMS. In addition, these coatings can serve as high-temperature solid lubricants. The integrated experimental and analytical approach is expected to transfer the next-generation hard material as well as advanced laser process technology to industry and supply high-quality products to manufacturing industries. Graduate and undergraduate students from both Mechanical Engineering and Materials Science and Engineering will benefit from hands-on research experience in preparation of nanocrystalline borides, advanced laser deposition of thin films, advanced machining, and MEMS fabrication.