Microstructure and Mechanical Properties of Nano-Carbon Reinforced Titanium Matrix/Hydroxyapatite Biocomposites Prepared by Spark Plasma Sintering

Abstract

Nano-carbon reinforced titanium matrix/hydroxyapatite (HA) biocomposites were successfully prepared by spark plasma sintering (SPS). The microstructure, mechanical properties, biocompatibility, and the relationship between microstructure and properties of biocomposites were systematically investigated. Results showed there are some new phases in sintered composites, such as β-Ti, TiO3, ZrO2, etc. Moreover, a small amount of Ti17P10, CaTiO3, Ca3(PO4)2 were also detected. The reaction that may occur during the preparation process is suppressed to some extent, which is because that the addition of second phases can prevent the direct contact of titanium with HA and reduce the contact areas. Transmission electron microscope (TEM) analysis proved the existence of elemental diffusion and chemical reactions in sintered composites. Compared with results of composites prepared by hot-pressed sintering before, mechanical properties (microhardness, compressive strength, and shear strength) of 0.5-GNFs composites prepared by SPS were increased by about 2.8, 4.8, and 4.1 times, respectively. The better mechanical properties of 0.5-GNFs composite in nano-carbon reinforced composites are mainly due to the lower degree of agglomeration of tubular carbon nanotubes (CNTs) compared to lamellar graphene nanoflakes (GNFs). Moreover, the strengthening and toughening mechanisms of nano-carbon reinforced titanium alloy/HA biocomposite prepared by spark plasma sintering (SPS) mainly included second phase strengthening, grain refinement strengthening, solution strengthening, graphene extraction, carbon nanotubes bridging, crack tail stripping, etc. In addition, in vitro bioactivity test revealed that the addition of nano-carbon was beneficial to promote the adhesion and proliferation of cells on the surface of titanium alloy/HA composite, because nano-carbon can enhance the formation of mineralized necks in the composites after transplantation, stimulate biomineralization and promote bone regeneration.

Evaluation of osteogenic and antibacterial properties of strontium/silver‐containing porous TiO2 coatings prepared by micro‐arc oxidation

“…That means, when Ag content in coatings reach 0.58 wt% (Sr/Ag0.17 group), both short‐term and long‐term antibacterial properties can be obtained. Some previous studies also explored the long‐term antibacterial properties of titanium coatings, 4,32 but their results were either achieved by a duplex technique or based on several change of immersion solution. The MAO technique used in this study is more simple and PBS for specimen immersion was changed every day.…”

“…Ag is the strongest element against microbes 3,4,6,14,23,24,26 and it can kill bacteria either in its ion form or by a mechanism of contact‐killing 28,30,32 . Direct contact of Ag with bacteria will cause destruction of cell wall and plasma membrane, leading to leakage of intracellular substances and eventually bacteria lysis 33,34 .…”

Effect of Graphene Nanosheets Content on Microstructure and Mechanical Properties of Titanium Matrix Composite Produced by Cold Pressing and Sintering

“…Many investigations have been focused on the manufacturing of CNT-reinforced titanium-based composites [13,28,29,30], but fewer studies and experiments have been conducted on the mechanical properties and microstructure of TMCs reinforced with graphene. Cao et al [31] fabricated titanium (Ti–6Al–4V)/graphene nanoflake (GNF) composites via hot isostatic pressing (HIP) followed by isothermal forging and reported that both the yield and ultimate tensile strengths were increased with the addition of GNFs to the matrix, without the loss of ductility.…”

Micro-Nano Carbon Structures with Platelet, Glassy and Tube-Like Morphologies

“…Tradition flake graphite (FG) (a major carbon source for carbon-containing refractories) does not meet the requirements of advanced steelmaking technology and low-carbon carbon-containing refractories (LCCRs). Moreover, researchers have devoted a lot of effort to developing LCCRs by adding nano-sized carbon sources [7,8,9]. First, carbon black (CB), as a zero-dimensional nano-sized carbon source, replaced FG partially or entirely.…”