Optical properties of models of porous ceramics based on hydroxyapatite

Abstract

Porous ceramics based on hydroxyapatite (HA) can be used in the reconstruction of damaged bone tissues. Porosity is an important physical property of ceramic materials and characterizes their structure. Porosity can be regulated by introducing of multi-walled carbon nanotubes (MWCNTs) additives into the ceramic matrix, which also increase the strength properties of the resulting composite. One of the noninvasive methods of studying the porous structure is the terahertz (THz) time domain spectroscopy. This method allows for non-destructive, non-contact and rapid assessment of optical properties, which is further necessary to study the porosity of HA based ceramic materials. Studies of optical properties require obtaining a variety of samples and processing a large amount of experimental data. To optimize the research and increase the speed of the task, digital models of ceramic samples were developed to study their optical properties.
In this paper, a computer experiment is considered to create structural models of a representative volume of HA ceramics without additives and with additives of 0.1 and 0.5 wt.% MWCNTs obtained using the finite element method. The transmission of THz radiation was simulated in the frequency range from 0.2 to 1.1 THz through the constructed models. The time delay of the pulse and the intensity of THz radiation depending on the frequency of radiation and porosity of ceramic models were determined based on the computer experiment.
A computer experiment showed that the addition of 0.1 and 0.5 wt.% MWCNTs leads to a small decrease of the porosity of the models from 25.98% to 25.71 and 25.24%, respectively. At the same time, an increase in nanotube concentrations leads to an increase of the intensity of transmitted THz radiation from 47.3 to 47.5 and 51.2 W/m2, as well as to an increase in the pulse time delay from 0.055471 ps to 0.055479 and 0.055572 ps, respectively, for samples without MWCNTs and with concentrations of 0.1 and 0.5 wt.%. The simulation results correspond to experimental data for ceramic samples based on HA with a similar concentration of MWCNTs [1].
Thus, a computer experiment made it possible to establish the correlation between porosity and optical properties of HA ceramics, which will further reduce the time spent on research by supplementing experimental data with simulation results.
The work was performed according to the Government research assignment for ISPMS SB RAS, subject number FWRW-2022-0002.

Referenses
1. Composite hydroxyapatite-multi-walled carbon nanotubes: study of porosity by terahertz time domain spectroscopy / A.E. Rezvanova, B.S. Kudryashov, A.N. Ponomarev, A.I. Knyazkova, V.V. Nikolaev, Y.V. Kistenev // Nanosyst.: Phys. Chem. Math. – 2023. – Vol. 14. – P. 530-538. – DOI: 10.17586/2220-8054-2023-14-5-530-538.

Speaker

Boris S. Kudryashov
Institute of Strength Physics and Materials Science SB RAS, Tomsk, Russia
Russia

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