Effects of the addition of boron nitride nanoplate on the fracture toughness, flexural strength, and Weibull Distribution of hydroxyapatite composites prepared by spark plasma sintering

Trevor G Aguirre; Corson L Cramer; Vincent P Torres; Thomas J Hammann; Troy B Holland; Kaka Ma

doi:10.1016/j.jmbbm.2019.01.021

Effects of the addition of boron nitride nanoplate on the fracture toughness, flexural strength, and Weibull Distribution of hydroxyapatite composites prepared by spark plasma sintering

J Mech Behav Biomed Mater. 2019 May:93:105-117. doi: 10.1016/j.jmbbm.2019.01.021. Epub 2019 Jan 31.

Authors

Trevor G Aguirre¹, Corson L Cramer², Vincent P Torres³, Thomas J Hammann¹, Troy B Holland¹, Kaka Ma⁴

Affiliations

¹ Mechanical Engineering Department, Colorado State University, Fort Collins, CO 80523, USA.
² Mechanical Engineering Department, Colorado State University, Fort Collins, CO 80523, USA; Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
³ Mechanical Engineering Department, Colorado State University, Fort Collins, CO 80523, USA; Pioneer Engineering, Fort Collins, CO 80524, USA.
⁴ Mechanical Engineering Department, Colorado State University, Fort Collins, CO 80523, USA. Electronic address: kaka.ma@colostate.edu.

PMID: 30785076
DOI: 10.1016/j.jmbbm.2019.01.021

Abstract

Hydroxyapatite (HA) has inherently low fracture toughness and low flexural strength, thus limiting it from wide scale application as an implant material in the biomedical field. To increase the fracture toughness and flexural strength, HA composites were fabricated by adding boron nitride nanoplatelets (BNNP) as reinforcement. Spark plasma sintering was utilized to achieve fine grain structure. The addition of BNNP facilitated grain size refinement. The BNNP reinforced HA composites exhibited increased fracture toughness (2.3 MPa m^1/2) and flexural strength (79.79 MPa) of HA over previous published values (1.0 MPa m^1/2). Despite that the Weibull Distribution indicated a sacrifice in mechanical reliability, all the composites fabricated in this study showed a low probability of failure and a factor of safety (~ 5.6) that is consistent with that of human bones (~ 6). In addition, the current study provides an approach to statistically design sintering parameters and mechanical loading for fabrication of ceramics.

Keywords: Boron-nitride nanoplates; Fracture toughness; Hydroxyapatite; Spark plasma sintering; Weibull analysis.

MeSH terms

Boron Compounds / chemistry*
Durapatite / chemistry*
Flexural Strength*
Materials Testing
Nanostructures / chemistry*
Plasma Gases / chemistry*
Surface Properties

Substances

Boron Compounds
Plasma Gases
boron nitride
Durapatite