This Small Business Innovation Research (SBIR) Phase I project seeks to develop an new methodology for the deposition of large-scale uniform and complex shape memory alloy parts. Current deposition methods cannot generate the uniform chemical composition, or the three dimensional geometric complexity, that is required for commercially relevant parts. In addition, the cost of current methods to manufacture TiNi, a key thin film shape memory alloy, is too high, limiting commercial acceptance. Chemical vapor deposition (CVD) of TiNi offers a means to manufacture geometrically complex parts inexpensively. In Phase I, our team will characterize a novel CVD process and characterize the resultant manufactured parts in terms of chemical composition, chemical uniformity, and contamination levels. This data will enable a transition to manufacturing of commercial shape memory devices in Phase II.
The broader impact/commercial potential of this project is the development of a new fabrication methodology that will allow for a dramatic reduction in the cost of thin film TiNi sheet products, stents, and open celled foams, by providing a means to manufacture highly consistent, uniform articles in a batch production process. For highly geometrically complex forms, such as high porosity open celled foams, this CVD process is an enabling manufacturing technology. Successful development of this process will revolutionize the thin film TiNi industry by finally supplying products to the marketplace with the required quality and batch-to-batch consistency for wide commercial acceptance.
Phase 1 Development of Chemical Vapor Deposition of the Shape Memory Alloy TiNi Thin Films for Complex Forms Submitted by: A.Peter Jardine, Principal Investigator Shape Change Technologies LLC Thousand Oaks, CA 91360 In the Phase 1 effort, the primary goal was to explore the chemistry by which inexpensive stock chemicals, Nickel Chloride and Titanium Chloride could be combined as vapors under vacuum (Chemical Vapor Deposition or CVD) to produce a thin metallic film of TiNi, also known as Nitinol. Thin film Nitinol has a variety of industrially important applications, primarily due to its remarkable Shape Memory Effect (SME) and Superelastic (SE) properties. SME and SE allows for Nitinol to be deformed with local strains of up to 8%, and then recovered by either heating in the case of the SME or when unconstrained, in the case of the SE. For example, a thin film Nitinol valve can be packed into a very small catheter and then deployed into the arterial system, enabling heart valve deployment in children. There are a variety of commercially significant applications that were identified as possible applications, in which the CVD deposition of Nitinol is an enabling step, due to its uniform chemistry and ability to have multiple parts manufactured at once. In this Phase 1 effort, Shape Change Technologies was successful in identifying two possible chemical processes that would generate thin film Nitinol. In addition to identifying these process parameters, geometrically complex valve structures and high porosity Nitinol foams were demonstrated to be coated uniformly, demonstrating the second objective of the effort in manufacturing complex parts.
