Bioceramic composites for orthopaedic applications: A comprehensive review of mechanical,biological, and microstructural properties

Bioceramics have been widely utilized for orthopaedic applications in which the biocompatibility and mechanical properties of the materials are vital characteristics to be considered for their clinical use. Till date, extensive studies have been devoted to developing a range of scientific ways for tailoring the microstructure of bioceramics in order to attain the trade-off of mechanical properties and biocompatibility of the final product. Owing to low reactivity, earlier stabilization and longer functional life of bioceramic, the developed implants are capable of replicating the mechanical behaviour of original bone. As the safety of the patient and its ultimate functionality are the ultimate goal of the selected implant material hence, the present literature survey investigates and brings forth the important aspects associated to the mechanical, biological and microstructural characteristics of bioceramics employed in orthopaedic applications. The review paper majorly focuses on effective utilization of various materials as an additive in bioceramics and processing techniques used for enhancement of properties, enabling the use of material in orthopaedic applications. The influence of various additives on the microstructure, mechanical properties and biological performance of developed bioceramics orthopaedic implants has been elaborately discussed. Furthermore, future prospects are proposed to promote further innovations in bioceramics research.     

Role of boron addition on phase composition,microstructural evolution and mechanical properties of nanocrystalline SiBCN monoliths

Nanocrystalline SiBCN monoliths with the same Si/C/N mole ratio and various boron additions ranged from 0 to 3.0 mol were prepared by mechanical alloying plus reactive hot pressing methods. Correction of boron content and microstructural/morphological evolution was investigated in detail by XRD, SEM, TEM and STEM-EDX structure characterization. Except for SiC and BN(C), boron addition contributes to B_xC formation. Besides, boron addition promotes the crystallization of SiC, leading to the formation of poor crystallinity of spherical structures in inner SiC. Furthermore, boron addition significantly promotes the grain growth of SiC and B_xC and therefore increases the relative volume ratios of B_xC/BN(C) and B_xC/SiC. Amorphous-like BN(C) changes to belt-like structures as boron addition increases. The new formed B_xC effectively contributes to the improvement of Vicker’s hardness while pull-out of BN(C) belt-like structures benefits the fracture toughness.     

Gelcasting and sintering of hydroxyapatite materials: Effect of particle size and Ca/P ratio on microstructural,mechanical and biological properties

The sintering behaviour and microstructural evolution of two batches of a commercial calcium-deficient hydroxyapatite powder were investigated. First, the sintered density as a function of the starting particle size distribution was studied, and the minimum particle size to get the desired target density was determined. Then, as the two batches were characterized by a slight difference in Ca/P ratio, the role of such ratio on phase and microstructural evolutions during sintering, as well as on mechanical and biological properties was investigated.It was observed that the powder with lower Ca/P ratio underwent significant hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) decomposition, with a simultaneous formation of tetracalcium phosphate (TTCP). The microstructure of sintered gelcast samples evolved during isothermal sintering at 1300 °C, moving from a starting homogeneous and narrow grain size distribution to a bimodal distribution after 3 h sintering. In fact, over time, large grains decomposed into smaller ones, finally providing a microstructure composed of coarse grains surrounded by plenty of ultra-fine grains. On the contrary, the powder with the higher Ca/P ratio provided a limited HA to β-TCP transformation, and normal grain growth by increasing the sintering time. Such differences lead to different mechanical properties for gelcast samples produced by the two powder batches, as the material with the lower Ca/P ratio affected by lower mechanical strength. Finally, sintered samples from both powders showed in-vitro bioactivity, with a larger surface coverage observed for the lower Ca/P ratio material. The morphology of the apatite layer seemed to be affected by the material composition, too, showing flake-like and needle-like morphologies depending on the Ca/P ratio of the starting powder.     

Up-conversion luminescence and temperature-sensing properties of Li+, K+ doped Na2Zn3Si2O8: Er3+ phosphors

In this work we detail the preparation of new luminescent Li⁺ and K⁺ doped Na₂Zn₃Si₂O₈: Er³⁺ up-conversion phosphors using the high-temperature solid-phase method. We investigate the phosphors phase structure, elemental distribution, up-conversion luminescence characteristics and temperature sensing properties. Our fabricated samples were found to be homogeneous and when excited using 980 nm light, they emitted wavelengths in the green and red visible wavelength bands, which correspond to two major emission bands of Er³⁺. Doping with Li⁺ and K⁺ increased the luminescence intensity of the Na₂Zn₃Si₂O₈: Er³⁺ phosphor at 661 nm by 36 and 21 times respectively. The highest relative temperature sensitivity (Sa) of the fabricated phosphor reached a value of 19.69% K^?1 and the highest absolute temperature sensitivity (Sr) reached 1.20% K^?1. These values are superior to other materials which utilize up-conversion by Er³⁺ ions as a tool for temperature sensing. We anticipate that these new phosphors will find significant application as components in optical temperature measurement systems.     

离子交换树脂脱除湿法磷酸中的铝和镁的研究

湿法磷酸中铝离子、镁离子影响其品质及后续磷酸盐的正常生产和产品质量。研究了一种新型离子交换树脂(IER-FC)对湿法磷酸中铝离子和镁离子的吸附净化效果。结果表明,IER-FC对Al~(3+)和Mg~(2+)的载荷量分别为0.003 218、0.015 500 g/g,脱除率分别为40%、85%,反应在10 min内达到平衡,反应温度对吸附净化的影响较小。     

Effect of Mn:Mg ratio on sintering behavior and microwave dielectric properties of (Mn,Mg)V2O6 ceramics at ultra-low sintering temperature

Ultra-low-firing-temperature ceramics (Mn_1−xMg_x)V₂O₆ (x = 0–1) were prepared using the conventional solid-state reaction method. The effects of the Mn:Mg ratio on the crystal structure and microwave dielectric properties of the prepared ceramics were systematically investigated. The results indicated that an appropriate Mn:Mg ratio effectively improves the dielectric properties of the compounds. Specimens with x = 0.01 and x = 0.93 sintered at 630 °C exhibited the following microwave dielectric properties: ε_r = 12.4 and 9.8, high Q×f = 57,000 and 21,000 GHz, and τ_f = –15 and −24 ppm/°C, respectively. This suggests that the (Mn_0.99Mg_0.01)V₂O₆ ceramic is a potential material for ULTCC applications.     

Effects of TiO2 on microstructural,mechanical properties and in-vitro bioactivity of plasma sprayed yttria stabilised zirconia coatings for dental application

One of the most compatible coatings, known as yttria-stabilised zirconia polycrystal (YZP) is deposited on metallic Ti alloys due to its excellent hardness and aesthetic value as well as its low affinity for plaques. However, poor bioactivities of YZP and the existence of micro crack propagations due to the aging of YZP may result in spontaneous implant failure thus limiting its clinical use. In this work, YZP coating reinforced titania (TiO₂), which is formed via a plasma spray technique was investigated in order to enhance the bioactivity and the mechanical properties of YZP coatings for dental implants. Based on microstructural studies performed on the deposited coating, a distinguished lamellar structure comprising YZP and TiO₂ was observed. It was found that the reinforcement of TiO₂ in YZP coating significantly reduced the crack due to the improved densities and the lamellar structure. The mechanical properties were also found to improve with 90% of hardness, 45% of adhesion strength and 54% of Young's Modulus with TiO₂ addition, which is desirable for dental implants. An in-vitro bioactivity test was then conducted by immersing the coatings in a simulated body fluid (SBF). As a result, an apatite formation was found on the YZP/TiO₂ coating surface after 3 days of immersion. Besides, it was verified in an XRD analysis that the crystalline TiO₂ was found in a rutile phase which was highly effective in generating apatite (natural mineral in human bones) on YZP coatings, proving that the bioactivities of the coating were significantly improved. Further studies were also performed on the SBF treatment, which took up to 14 days also demonstrated that only a small decrease in hardness was noted, indicating that YZP/TiO₂ coatings had reached an excellent mechanical stability.     

Thin-Layer Chromatography of Metal Ions in Formic Acid Medium on Impregnated and Unimpregnated Silica Gel G: Semiquantitative Determination of Fe3+, Cd2+, Th4+, Al3+, Zn2+, UO2+ 2, VO2+, Ce4+, and Ni2+

Abstract

The adsorption behavior of metal ions in the formic acid-sodium formate system using unimpregnated as well as impregnated silica gel G as thin layers has been studied. A remarkable result of this study is the dramatic selectivity of impregnated silica gel G thin layers when compared to the corresponding unimpregnated silica gel G thin layers. This impregnation effect provides us with a new adsorbent phase which is sufficiently stable in the formic acid-sodium formate medium. Some important ternary separations have been achieved on silica gel G thin layers. Al³⁺, Ni²⁺, Fe³⁺, and Pb²⁺ have been qualitatively separated from mixtures of other ions. Cu²⁺ has been selectively separated on impregnated silica gel G thin layers. The semi-quantitative determination of nine metal ions on impregnated silica gel G layers has also been attempted.     

Comprehensive study on structural,thermal, morphological and luminescence (RL,PL, TL) properties of CaLa2(WO4)4: Tb3+, Dy3+ phosphors synthesized via sol-gel method

Tb³⁺/Dy³⁺ co-doped CaLa₂(WO₄)₄ (CLW: Tb³⁺/Dy³⁺) and its derivatives were synthesized by the sol-gel method. The morphology, thermal, structure and luminescent-optical properties the as-prepared light-emitting phosphors were characterized by utilizing scanning electron microscopy (SEM), differential thermal analysis (DTA)-thermogravimetric analysis (TG), X-ray diffraction (XRD) and radioluminescence (RL or X-ray luminescence) - photoluminescence (PL) –thermoluminescence (TL or TSL) - optical absorption spectrometry. The Tb³⁺ and Dy³⁺ ions were singly or doubly doped and the results were examined in detail. Moreover, for these phosphors, the energy transfer mechanisms which depend on RL and PL spectra were determined. The samples excited by X-ray demonstrate characteristic luminescence peaks of Dy³⁺ (422, 480, 575, 663 and 747 nm) and Tb³⁺ (489, 544, 586, 620, 652 and 675 nm). These emissions are similar for RL and PL measurements. It could be said that the energy transfer efficiency of the host material is perfect for rare-earth ions. The synthesized phosphors exhibit various colors from yellow to blue under UV excitation. The optical band gaps of host CLW, CLW: Tb³⁺, CLW: Dy³⁺ and co-doped CLW: Tb³⁺/Dy³⁺ were calculated at values 3.83 eV, 3.44 eV, 3.64 eV and 3.52 eV, respectively. From the results obtained, the CaLa₂(WO₄)₄: Tb³⁺, Dy³⁺phosphors may be one of the potential candidates for light-emitting diode.     

A comparison study of tialite ceramics doped with various oxide materials and tialite–mullite composites: microstructural,thermal and mechanical properties

Tialite (Al₂TiO₅) is a material of very low thermal expansion coefficient, high thermal shock resistance, high refractoriness and good corrosion resistance. However, its applications are very limited due to its low mechanical strength and to its thermal instability in the temperature range 750–1350 °C, which leads to the decomposition of the material to its parent oxides alumina and rutile. To overcome both problems, stabilization of the structure is tried through doping with various oxides; in the present work, a comparison study of the properties that can be achieved and of the decomposition behavior of tialite ceramics stabilized by adding MgO, talc or feldspar and of tialite–mullite composites made by the addition of kaolin is carried out. The processing conditions are also investigated for preparing porous ceramics for applications in the area of soot traps and hot gas clean-up. It was found that talc addition has an excellent stabilizing behavior, whereas tialite–mullite composites exhibit increased strength. Such composites with 10–20 wt.% mullite present the appropriate properties for the applications under consideration. Mullite presence also brings a stabilizing effect, thus in combination with talc additions it could lead to a very stable product.     

Apatite oxynitride phosphor (Mg,Y)5Si3(O,N)13:Ce3+,Mn2+: A single-phased host with solar-like and efficient emission

During pursuing high color rendering index for full-color-emitting phosphor, low quantum efficiency (QE) is usually accompanying. We intend to elevate the luminescence efficiency when realizing a solar-like spectra distribution, by constructing apatite structure oxynitride, inheriting high covalence and rigidity from oxynitride, and suitable multiple cation sites from oxyapatite compounds. Full-color-emitting apatite structure oxynitride phosphor (Mg,Y)₅Si₃(O,N)₁₃:Ce³⁺,Mn²⁺ has been prepared, and the crystal sites’ occupancies of activators in this host were favorable for white emission. (Mg,Y)₅Si₃(O,N)₁₃:Ce³⁺,Mn²⁺ phosphor shows whole visible light with emission wavelength ranging from 370 to 750 nm, matching the spectra of sunlight quite well. The fabricated white light-emitting diode lamp demonstrated the distinctive overall performance of QE and chromaticity properties (R_a and R₉). Furthermore, correlated color temperature is tunable from cool nature to warm white. The obtained lamp possesses the feature of less blue light hazard and high saturation of red degree, compared with the commercial YAG-based lamp.     

Effect of carburizing treatment on microstructural,mechanical and tribological performances of Cr doped DLC coating deposited on Ti6Al4V alloy

Cr doped diamond-like carbon (DLC) coating was deposited on the carburized Ti6Al4V alloy (TA) by magnetron sputtering (MS). The physical and chemical characteristics of Cr doped DLC coating were obtained using scanning electron microscope, energy dispersive spectroscope, Raman spectrometer, X-ray photoelectron spectroscopy and Fourier transform infrared, and the mechanical property and adhesion force were analyzed by nanoindenter and scratch tester. The effects of carburizing treatment on the coefficient of friction (COF) and wear mechanism of Cr doped DLC coatings were investigated on a ball-on-disk tribometer. The results show that the adhesion force and mechanical property of Cr doped DLC coating deposited on the carburized TA are higher than those deposited on the original TA. The average coefficients of friction (COFs) of Cr doped DLC coatings deposited on the original and carburized TAs under the dry-friction condition are 0.157 and 0.143, respectively, showing that the carburizing treatment has the obvious effect of friction reduction for the Cr doped DLC coating. The wear mechanism of Cr doped DLC coating deposited on the carburized TA is combined action of abrasive wear and adhesive wear, which are contributed to the enhancement of mechanical property of Cr doped DLC coating by carburization treatment. Furthermore, the average COFs of Cr doped DLC coatings deposited on the original and carburized TAs under the oil-lubrication condition are 0.152 and 0.131, respectively, which are superior to those under the dry-fiction condition. The carburizing treatment promotes the formation of self-repairing carbonyl of Cr doped DLC coating, and the oil-wet characteristic of Cr doped DLC coating with the aromatic aldehyde of CO as the functional group plays the main role of friction reduction.     

Effect of modified Mg2B2O5w on mechanical and friction properties of oil-containing monomer casting nylon

The Mg₂B₂O₅w modified by toluene-2, 4-diisocyanate (TDI) and fatty amine (n-dodecylamine(D) or n-octadecylamine (O)) was used in oil-containing monomer casting (OMC) nylon, and the effect of modified Mg₂B₂O₅w on mechanical and friction properties of OMC nylon composites was investigated. The significant improvement of the mechanical and friction properties of composites was observed. The addition of 0.15 wt% TDI-D-Mg₂B₂O₅w or TDI-O-Mg₂B₂O₅w resulted in 21 and 20% growth in the tensile strength, 53 and 52% increase in the flexural strength, respectively. Additionally, nearly 60 and 58% reduction in the friction coefficient, about 84 and 80% decrease in the abrasion quantity. Furthermore, the worn surface of composites exhibited smooth, which confirmed the antiwear effect of Mg₂B₂O₅w. The improvement was attributed to the interfacial adhesion between whiskers and matrix by hydrogen bonds. This work provided a facile approach to the design of wear-resistant polymer composites that hold significant potential in construction machinery industry. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48856.     

A review of surface topographical modification strategies of 3Y-TZP: Effect in the physicochemical properties,microstructure, mechanical reliability,and biological response

The development of zirconia dental implants has become increasingly popular over the last years due to the outstanding mechanical properties, superior aesthetic appearance and high biocompatibility of this material. However, premature implant failure as a result of an incomplete osseointegration still represents a major concern. In this sense, surface modifications have been applied to dental zirconia to improve the biological interactions of the implant with the surrounding tissue. Nevertheless, surface modification of zirconia is challenging due to the formation of a monoclinic phase associated with ageing and loss of mechanical integrity. This review focuses on the most common surface topographical modification strategies currently applied to zirconia, namely grinding, sandblasting, chemical etching and laser treatment. A comprehensive and comparative analysis has been performed to assess the effects of these techniques on the physicochemical properties, mechanical performance, hydrothermal degradation behavior and biological response of the modified surfaces.     

Synthesis of a novel inorganic cation exchanger based on molybdate: Applications for removal of Pb2+, Fe3+ and Mn2+ ions from polluted water

A novel manganese phosphomolybdate exchanger was synthesized, dried at different temperatures, and evaluated for the elimination of lead, iron, and manganese ions from aqueous solutions. The chemical structure of the cation exchanger was established using Fourier-transform infrared, scanning electron microscopy, Thermo gravimetric analysis/ Differential thermal analysis, and X-ray diffraction. The adsorption performance of the heavy metals Pb²⁺, Fe³⁺, and Mn²⁺ toward the synthesized material has been studied. The obtained outcomes show that the selectivity of the cationic exchanger was descending in this order, Pb²⁺ > Fe³⁺ > Mn²⁺. The highest adsorption capacity was shown to be decreased as drying temperature of the exchanger increases from 50°C to 800°C.     

Microstructure and mechanical properties of Si3N4f/BN composites with BN interphase prepared by chemical vapor deposition of borazine

The boron nitride (BN) interphase of silicon nitride (Si₃N₄) fiber-reinforced BN matrix (Si₃N_4f/BN) composites was prepared by chemical vapor deposition (CVD) of liquid borazine, and the microstructure, growth kinetics and crystallinity of the BN coating were examined. The effects of coating thickness on the mechanical strength and fiber/matrix interfacial bonding strength of the composites were then investigated. The CVD BN coating plays a key role in weakening the interfacial bonding condition that improves the mechanical properties of the composites. The layering structure of the BN coating promotes crack propagation within the coating, which leads to a variety of toughening mechanisms including crack deflection, fiber bridging and fiber pull out. Single-fiber push-out experiments were performed to quantify the fiber/matrix bonding strength with different coating thicknesses. The physical bonding strength due to thermal mismatch was discussed.     

Characterization of crystal structure and microwave dielectric properties of AZrNb2O8 (A=Zn,Co, Mg,Mn) ceramics based on complex bond theory

Single phase AZrNb₂O₈ (A=Zn,Co,Mg,Mn) ceramics with monoclinic wolframite structure were prepared and characterized by crystalline structure refinement for the investigation on the correlations between crystal structure and microwave dielectric properties. A semiempirical method based on the complex bond theory was used to calculate the bond ionicity, lattice energy, and coefficient of thermal expansion of AZrNb₂O₈ ceramics. The crystal structure changed with the variation of A site ions and affected the Nb–O octahedral correspondingly. Due to the variation of crystal structure, the observed bond ionicity was helpful to understand the electric polarization. The variation of the Q·ƒ and τ_ƒ values could be attributed to the lattice energy and coefficient of thermal expansion respectively. The microwave properties of AZrNb₂O₈ ceramics were strongly dependent on the chemical bond ionicity, lattice energy and coefficient of thermal expansion.     

Ce3+ doped Lu3Al5O12 ceramics prepared by spark plasma sintering technology using micrometre powders: Microstructure,luminescence, and scintillation properties

Ce³⁺ doped Lu₃Al₅O₁₂ (Ce:LuAG) ceramics were fabricated by the solid-state reaction method through spark plasma sintering (SPS) from 1350 °C to 1700 °C for 5 min at a pressure of 50 MPa using micro powders. The average grain size of the SPSed ceramics gradually grew from 0.42 µm (1400 °C) to 1.55 µm (1700 °C), which is nearly one order of magnitude lower than that of vacuum sintered (VSed) Ce:LuAG ceramics (~24.6 µm). Characteristic Ce³⁺ emission peaking at around 510 nm appeared and 92% photoluminescence intensity of room temperature can be reserved at 200 °C revealing excellent thermal stability. The maximum radioluminescence intensity reached around 3 times of VSed Ce:LuAG ceramics and 7.8 times of BGO crystals. The maximum scintillation light yield under γ-ray (¹³⁷Cs) excitation reached 9634 pho/MeV @ 2 μs. It is concluded that SPS technology is a feasible way to develop Ce:LuAG ceramics and further optical enhancement can be expected.