Sintering of Additively Manufactured Hydroxyapatite Embedded With Boron Nitride Nanotubes
Abstract
As technologies like hypersonics develop, the need for advanced ceramic and composite materials becomes more urgent. These materials must have unique geometries and exceptional materials properties like high melting (or decomposition) temperature, low thermal conductivity, and high thermal shock resistance. In many cases, the only way to achieve the required geometry is by additive manufacturing. Furthermore, ceramic parts often need to be reinforced with nanoparticles to achieve the desired properties. This presents an issue since the high temperature of ceramic post-processing can degrade or even destroy these nanoparticles. This thesis sought to identify a method to sinter a 3D-printed ceramic while keeping the embedded nanoparticles intact. This work focused on hydroxyapatite [CA10(PO4)6(OH)2] embedded with boron nitride nanotubes (BNNTs). The samples were heat treated in argon using a tube furnace. The temperature and the sintering medium were varied to determine the ideal process. After post-processing, the samples were evaluated using X-ray diffraction, scanning electron microscope analysis, and the Archimedes method. No significant trends in the density were noted throughout testing; however, it was found that samples that were sintered in a boron nitride powder medium displayed intact BNNTs post-sintering. This demonstrated that BNNTs can survive temperatures far above their oxidation point if the environment is carefully controlled.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2023
- Accession Number
- AD1213563
Entities
People
- Nathan J. Matalavage
Organizations
- Naval Postgraduate School