Novel mechanochemical routes for cubic boron nitride synthesis from templated polymerized borazine precursors
Abstract
Construction of new advanced naval vessels, vehicles and aircrafts and their repair when damaged in battle or otherwise needing maintenance requires the best possible tools and metalworking procedures and significantly affects the combat competitiveness of armed forces. Complex underwater repairs to surface ships and submarines also require best performing and most reliabletools. Friction stir welding (FSW) is a solid-state welding process which is capable of joining materials difficult to weld by the conventional fusion welding and can be performed underwater. Possibility of underwater FSW repair of ship and submarine control surfaces and hulls provides great benefits by eliminating the need for dry-docking and extensive environmental control procedures. The most significant bottleneck for further development of the FSW technology isavailability of suitable advanced superhard materials for cutting tools. Cubic phase of boron nitride (cBN) is the best available superhard material from which cutting tools for FSW are made. cBN is characterized by very desirable abrasive properties, including high hardness, strength, abrasion resistance, and thermal and chemical resistance. cBN is not thermodynamically stable atambient conditions, and its synthesis is typically performed under high pressure and temperature conditions, and in very small batches, which makes it prohibitively expensive. The Extreme Materials research group of the PI at the University of Hawaii specializes in in situ monitoring of phase changes and chemical reactions at conditions of high pressure and hightemperature. In this project we will explore possibilities of much more economical and easily scalable synthesis of cBN through an innovative combination of mechanochemical processing and thermolysis of borazine-derived precursors, templated within BN-nanostructures.We will conduct thorough in situ real-time analysis of the synthesis process using state of the art synchrotron-radiation-based methods to develop comprehensive understanding of the factors controlling the process, its kinetics, and nature of all intermediates, and will characterize the properties, structure and performance of the resulting cBN products obtained using these newmethods.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 20, 2019
- Source ID
- N000141912578
Entities
People
- Przemysław Dera
Organizations
- Office of Naval Research
- United States Navy
- University of Hawaiʻi System