Ti3SiC2 Ceramics Research Articles

Porous Ti3SiC2 ceramics with improved osteogenic functions via biomineralization as load-bearing bone implants

Ti3SiC2 ceramics exhibit excellent mechanical properties and good biocompatibility, rendering them promising bone substitutes for load-bearing conditions. However, the bone integration and osteogenic ability of Ti3SiC2 ceramics remain unclear. Herein, porous Ti3SiC2 ceramics were prepared and systematically investigated as bone scaffolds. The Ti3SiC2 scaffolds with a porosity of 62.9 % ± 2.5 % showed high compressive strength ∼68.12 ± 4.33 MPa. Silicon hydroxyl groups formed on the surface of Ti3SiC2 after soaking in simulated body fluid, which played a critical role in the apatite mineralization of the scaffolds. Biomineralization of Ti3SiC2 scaffolds was found when implanted subcutaneously in the rat dorsum for 2 weeks, demonstrating good osteogenesis ability. The apatite mineralization of the Ti3SiC2 scaffold facilitated the polarization of RAW264.7 cells from M1 to M2 phenotype, which also promoted the differentiation of MC3T3-E1 cells. The porous Ti3SiC2 scaffolds improved osteointegration and bone regeneration after implantation in rabbit femoral defects. Impressively, the number of the newly formed trabeculae in the Ti3SiC2 group was three times of the control group after implantation for 8 weeks, showing excellent bone defect repair. This work demonstrates that Ti3SiC2 implants with improved biological functions likely via in-situ biomineralization are promising candidates for bone regeneration.

The Chip Formation Process When Cutting High-Speed Steels and Ti3SiC2 Ceramics

The paper presents the microstructural characterization of the chip roots in high-speed steels and ceramic Ti3SiC2. The process of chip formation and the obtaining of adequate samples were carried out using the quick-stop method. The tests were carried out during the milling process; the “quick stop” method was carried out in order to obtain samples of the chip roots. This method was developed in-house by the authors. The chip roots were microscopically studied by means of a light microscope (LM) and a scanning electron microscope (SEM). Before the actual analysis, preparation was performed based on the standard metallographic technique. The analysis of the high-speed steels samples showed that, for the used cutting conditions, a discontinuous chip with a built-up edge (BUE) was formed. During the processing of the Ti3SiC2 ceramic, a significant difference was manifested in the chip formation process and a powder-like chip was produced. After utilizing a careful cutting process, a chip pattern was observed, from which it is evident that chip breakage during ceramic processing occurs without prior plastic deformation. In addition, the cutting force Fc was also measured during the milling process of the high-speed steels and the ceramic, and it was correlated with the cutting speed, feed per tooth and depth of cut.

Ice-templated assembly strategy to construct oriented porous Ti3SiC2 ceramics for thermal management and electromagnetic interference shielding in harsh thermal environments

Given the electromagnetic interference (EMI) and heat aggregation issue faced by electronic components, an urgent need exists to integrate EMI shielding and thermal conductivity in one material. Herein, a novel lightweight porous Ti3SiC2 ceramic with ordered structural arrangement was fabricated by using budget-friendly raw materials through ice template design and in-situ reaction synthesis. Leveraging the excellent conductivity and thermal conductivity of Ti3SiC2, a dual-functional advanced material with efficient EMI shielding and thermal management capabilities was obtained. At room temperature, porous Ti3SiC2 ceramics can achieve a shielding effectiveness of 35.44 dB and a thermal conductivity of 12.17 W/mK, with performance that can be tuned by porosity. In further, the porous Ti3SiC2 ceramic can work stably in thermal environments from room temperature to 700 °C or in corrosive environments rich in acid, alkali, and salts due to its excellent high temperature oxidation resistance and corrosion resistance. In view of the dual-functional characteristics and the stability of operation in harsh thermal environments, ordered porous Ti3SiC2 ceramics are promising for modern maritime and aerospace applications.

Experimental investigation and mathematical modelling of water vapour corrosion of Ti3SiC2 and Ti2AlC ceramics and their mechanical behaviour

Commercially available Ti3SiC2 and Ti2AlC ceramics were used in this study to investigate their wet corrosion and mechanical behaviour as they were under investigation for years for their applications in the field of nuclear as cladding materials and aerospace. The test coupons of dimension 3 × 4 × 40 mm3 and 3 × 4 × 20 mm3 were machined out from commercially available samples for the 3-pt bend test and wet corrosion test, respectively. The water vapour corrosion studies of these samples were carried out at 800 ℃, 1000 ℃, 1200 ℃ for 10, 20 and 100 h in gas flow condition containing 50 % steam + 50 % air. Phase analysis of the as-received Ti3SiC2 and Ti2AlC ceramics revealed the presence of other impurity phases such as TiC and TiSi2. The XRD patterns of the oxidised samples show the formation of rutile as the major phase in both materials. The oxidation layer formed on Ti3SiC2 sample was measured to be 280 μm after exposing the sample in steam for 100 h at 1200 °C. The water vapour corrosion studies reveal that Ti2AlC has high oxidation resistance compared with the Ti3SiC2 due to the formation of protective layers of TiO2 and Al2O3 which resulted in reduced weight gain and oxidation layer thickness. Three-point bend tests were conducted at room temperature for the samples after the water vapour corrosion test at 1000 °C/100 h. The TAC samples showed no degradation in the bending strength (244 MPa) whereas the TSC samples showed reduced strength of 320 MPa. The tensile strength of the samples was measured at room temperature and hydrothermal condition (250 °C and 250 bars pressure) and it was observed that Ti3SiC2 had high tensile strength (190 MPa) in hydrothermal conditions. The tensile strength results were validated using Finite element analysis (FEA) using ANSYS and the FEA results showed a negligible variance of 7 % compared with experimental method. Mathematical modelling based on one dimensional solution of diffusion equation combined with Deal-Grove model was employed to study and compare the oxidation thickness for the linear and parabolic models for the ceramics. The model was effective in validating the oxidation thickness of Ti3SiC2 showing that the experimental thickness was closer to that of mathematical model.

Permittivity tunable by Ti3SiC2 ceramics in sandwich-structured polymer composites

To further promote the progress of the embedded mold packaging technology in circuit board, polymer-based composites with alternating positive and negative permittivity layer have been designed. Compared with single-layer materials, permittivity in this work is increased from 113 to 250 at 100 Hz in BFT/PVDF–Ti3SiC2/PVDF–BFT/PVDF sandwich structure, with the loss tangent’s decreasing from 0.97 to 0.78. As negative permittivity layer filler, the Ti3SiC2 with optimistic interfacial polarization is ascribed to the flake structure and contributes to improving the permittivity, resulting in good insulation behavior and temperature stability at the same time. It is expected to provide new ideas for investigating high-permittivity polymer–matrix composites in this work.

C0.3N0.7Ti-SiC Toughed Silicon Nitride Hybrids with Non-Oxide Additives Ti3SiC2.

In situ grown C0.3N0.7Ti and SiC, which derived from non-oxide additives Ti3SiC2, are proposed to densify silicon nitride (Si3N4) ceramics with enhanced mechanical performance via hot-press sintering. Remarkable increase of density from 79.20% to 95.48% could be achieved for Si3N4 ceramics with 5 vol.% Ti3SiC2 when sintered at 1600 °C. As expected, higher sintering temperature 1700 °C could further promote densification of Si3N4 ceramics filled with Ti3SiC2. The capillarity of decomposed Si from Ti3SiC2, and in situ reaction between nonstoichiometric TiCx and Si3N4 were believed to be responsible for densification of Si3N4 ceramics. An obvious enhancement of flexural strength and fracture toughness for Si3N4 with x vol.% Ti3SiC2 (x = 1~20) ceramics was observed. The maximum flexural strength of 795 MPa for Si3N4 composites with 5 vol.% Ti3SiC2 and maximum fracture toughness of 6.97 MPa·m1/2 for Si3N4 composites with 20 vol.% Ti3SiC2 are achieved via hot-press sintering at 1700 °C. Pull out of elongated Si3N4 grains, crack bridging, crack branching and crack deflection were demonstrated to dominate enhance fracture toughness of Si3N4 composites.

Fabrication and tribological behaviors of Ti3SiC2/Ti5Si3/TiC/Ni-based composite coatings by laser cladding for self-lubricating applications

In the work the in-situ synthesis of Ti3SiC2 (MAX) phase and silicide reinforced Ni-based composite self-lubricating coatings from Ti-Si-C system and NiCrBSi powders were carried and initiated by laser cladding with use of 5 kW fiber laser beam with 3 mm spot. The microstructures of the laser-clad in situ synthetic self-lubricating coatings were analyzed by a scanning electron microscope (SEM) equipped with an X-ray energy dispersive spectrometer (EDS). An X-ray diffraction (XRD) spectrometer and an electron back-scattered diffraction (EBSD) were used for determination of the reaction products in the composite coatings. The friction and abrasion behavior of the coatings were evaluated at room temperature by a dry sliding friction tester. The results indicate that in-situ chemical reactions took place between elements Ti, Si and C in the laser molten pool, and the reaction products included Ti3SiC2, Ti5Si3, and TiC ceramics as well as TiNix compound. Finally, three laser-clad Ti3SiC2/Ti5Si3/TiC/Ni-based composite coatings with the total thickness about 1 mm were fabricated on Ti6Al4V alloy. The average microhardness of the three coatings was 703.2 HV0.2, 751.9 HV0.2 and 850.6 HV0.2 respectively, which has been significantly improved, compared with the hardness of Ti6Al4V substrate (about 360 HV0.2). The average friction coefficient of the Ti3SiC2/Ti5Si3/TiC/Ni-based composite coating (50 wt% Ni25/50 wt% Ti-Si-C) reduced to 0.33 at room temperature, and it exhibited the wear rate of 13.5 × 10−5 mm3 N−1 m−1. The laser cladding Ti3SiC2/Ti5Si3/TiC/Ni-based composite coatings characterized by small amount of adhesive wear, plastic deformation and relatively smooth wear surface could be observed.

Corrosion of Ti3SiC2 ceramics in a high-temperature CO environment

Abstract We report the results of our experiments on cyclic exposure of Ti3SiC2 ceramics to CO environment at high temperature. The growth of a two-layer scale composed of a dense outer layer containing β-SiC and TiC microcrystals, and a porous inner layer of TiC microcrystals was observed. The corrosion was accompanied by the release of SiO gas, which then took part in the growth of β-SiC microcrystals in the upper part of the outer layer by the reaction with CO gas.

In-situ reaction of Ti-Si-C composite powder and formation mechanism of laser deposited Ti6Al4V/ (TiC+Ti3SiC2) system functionally graded material

Ti-Si-C composite powder was designed as raw material for laser deposition, and fabricated into quasi-spherical powder particles. On this basis, Ti6Al4V/(TiC+Ti3SiC2) system functionally graded material (FGM) was designed and fabricated using pure Ti powder and the fabricated Ti-Si-C composite powder. The microstructures of the gradient layers were analyzed by a scanning electron microscope (SEM) equipped with an X-ray energy dispersive spectrometer (EDS). An X-ray diffraction (XRD) spectrometer and a transmission electron microscope (TEM) were used for determination of the reaction products in the gradient layers. In-situ chemical reactions took place between elements Ti, Si and C in the deposited layers, and the reaction products included TiC and Ti3SiC2 ceramics as well as Ti5Si3 compound. Finally, Ti6Al4V/(TiC+Ti3SiC2) system FGM with a planar size of 25 mm × 50 mm was fabricated and the total thickness of all the graded layers was 2.2 mm. The average three-point bending strength of the overall Ti6Al4V/(TiC+Ti3SiC2) system FGM was high up to 995 MPa at room temperature, and the outermost layer exhibited the microhardness of 647.5 HV.

Electromagnetic interference shielding performance of nano-layered Ti3SiC2 ceramics at high-temperatures

The X-band electromagnetic interference (EMI) shielding properties of nano-layered Ti3SiC2 ceramics were evaluated from room temperature up to 800°C in order to explore the feasibility of Ti3SiC2 as efficient high temperature EMI shielding material. It was found that Ti3SiC2 exhibits satisfactory EMI shielding effectiveness (SE) close to 30 dB at room temperature and the EMI SE shows good temperature stability. The remarkable EMI shielding properties of Ti3SiC2 can be mainly attributed to high electrical conductivity, high dielectric loss and more importantly the multiple reflections due to the layered structure.

Fabrication of Ti3SiC2 and Ti4SiC3 MAX phase ceramics through reduction of TiO2 with SiC

Ti3SiC2 and Ti4SiC3 MAX phase ceramics were fabricated through high-temperature vacuum reduction of TiO2 using SiC as a reductant, followed by hot pressing of the products under 25MPa of pressure at 1600°C. It was found that both Ti3SiC2 and Ti4SiC3 may be obtained in good yields, depending on the annealing time during the reduction step. In addition to MAX phases, the products contained some amounts of TiC. The hot pressing step did not significantly affect the composition of the products, indicating good stability of Ti3SiC2 and Ti4SiC3 under these conditions. Analysis of the densification behavior of the samples revealed lower ductility in Ti4SiC3 compared to Ti3SiC2. The samples prepared herein exhibited the flexural strength, fracture toughness and microhardness typical of coarse-grained MAX-phase ceramics.

Effects of infiltration parameters on the synthesis of nano-laminated Ti3SiC2

ABSTRACTIn this paper, the nano-laminated Ti3SiC2 ceramics were fabricated by liquid silicon infiltration of gelcast porous titanium carbide (TiC) preforms. The phase compositions and microstructures of the synthesized samples at various infiltration times and temperatures were analyzed by the X-ray diffraction (XRD) technique and were observed by field emission scanning electron microscopy (FESEM). The results showed that the formed Ti3SiC2 decomposes to the TiC phase with the increase of infiltration time. It was found from the XRD patterns that the samples with an 88 wt% Ti3SiC2 MAX phase can be produced with infiltration at 1500°C for 1 h with 50 vol% solid loading and 10 wt% monomer content. It is found that the hardness and flexural strength of Ti3SiC2-based ceramic has been reduced with a decrease in SiC and TiC impurities and reach 5.8 GPa and 420 MPa, respectively, for the sample with 15 wt% impurity. The microstructure evaluation revealed that the purity and properties of samples were affected both through the gelcasting and infiltration parameters.

Pore Formation Process of Porous Ti3SiC2 Fabricated by Reactive Sintering.

Porous Ti3SiC2 was fabricated with high purity, 99.4 vol %, through reactive sintering of titanium hydride (TiH2), silicon (Si) and graphite (C) elemental powders. The reaction procedures and the pore structure evolution during the sintering process were systematically studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). Our results show that the formation of Ti3SiC2 from TiH2/Si/C powders experienced the following steps: firstly, TiH2 decomposed into Ti; secondly, TiC and Ti5Si3 intermediate phases were generated; finally, Ti3SiC2 was produced through the reaction of TiC, Ti5Si3 and Si. The pores formed in the synthesis procedure of porous Ti3SiC2 ceramics are derived from the following aspects: interstitial pores left during the pressing procedure; pores formed because of the TiH2 decomposition; pores formed through the reactions between Ti and Si and Ti and C powders; and the pores produced accompanying the final phase synthesized during the high temperature sintering process.

Characterization of Thermomechanical Behavior of Ti3SiC2 and Ti2AlC Ceramics Elaborated by Spark Plasma Sintering Using Ultrasonic Means

In order to better understand the thermomechanical behaviors of Ti3SiC2 and Ti2AlC ceramics, sintered by spark plasma sintering process (SPS), ultrasonic pulse echography in “long bar mode” (US) and acoustic emission (AE) techniques are applied. High‐temperature investigations of the evolution of Young's modulus (E) and AE activity are carried out up to 1 473 and 1 623 K. Results show a decrease of E with increasing temperature which is more marked around maximal temperature of the thermal cycle for Ti2AlC material. Moreover, the increase of the maximal temperature of the thermal cycle influences the number of recorded cumulated hits. Both measurements (US + AE) highlight the role of the plastic deformation mechanism (motion of dislocation) activated over the brittle‐to‐plastic transition temperature.

Evaluation on diffusion bonded joints of TiAl alloy to Ti3SiC2 ceramic with and without Ni interlayer: Interfacial microstructure and mechanical properties

Diffusion bonding of TiAl alloys and Ti3SiC2 ceramics were carried out in a vacuum atmosphere. The microstructures and mechanical properties of the bonded joints were investigated. Results showed that three coherent intermetallic layers formed in the TiAl/Ti3SiC2 joints during bonding process. The compound layer adjacent to Ti3SiC2 substrate was indicated to be Ti5Si3, in which brittle fracture of the joints took place during shear strength test. The properties of diffusion bonded joints were greatly improved attributed to the formation of a good transition in the joint as well as the relief of the residual stress when using Ni foil as interlayer. Formation mechanisms of the compound layers during bonding process were discussed. Shear test results showed that the maximum shear strength reached 52.3MPa. Corresponding fractograph indicated that the crack mainly propagated along Ti3SiC2 substrate adjacent to the bonding zone, accompanied with an intergranular and transgranular fracture mode.

Fabrication of textured Ti<sub>3</sub>SiC<sub>2</sub> ceramic by slip casting in a strong magnetic field and pressureless sintering

Sinterable Ti3SiC2 powder was synthesized from a powder mixture with a molar ratio of 1.0Ti:0.3Al:1.2Si:2.0TiC by heating at 1200°C in Ar flow. Almost single-phase peaks of Ti3SiC2 were observed in X-ray diffraction patterns. The powder was dispersed in ethanol using polyethylenimine (PEI) as the polymer dispersant. Textured dense Ti3SiC2 ceramics were successfully fabricated by slip casting in a strong magnetic field followed by pressureless sintering at 1400°C for 2 h. The relative density of these Ti3SiC2 ceramics was 99.4%, and the bending strength, fracture toughness and electrical resistivity were 623 ± 9 MPa, 5.9 ± 0.1 MPa·m1/2 and 0.31 µΩ·m, respectively. Compared with those of nontextured pressureless sintered samples of almost full density, the bending strength and fracture toughness of the textured Ti3SiC2 ceramics were increased by factors of 1.6 and 1.4, respectively.

Fabrication of Textured Ti3SiC2 Ceramics by Slip Casting in a Magnetic Field and Pulsed Electric Current Sintering

Fabrication of Textured Ti3SiC2 Ceramics by Slip Casting in a Magnetic Field and Pulsed Electric Current Sintering

Synthesis of Ti<sub>3</sub>SiC<sub>2</sub> Machinable Ceramics by High-Energy Milling and Hot-Pressing

The ternary layered machinable Ti3SiC2 ceramics were synthesized at 1300°C by high-energy milling and hot pressing sintering using Ti,Si and C powder as starting material. The reaction mechanism was examined by XRD, SEM and thermodynamic analysis. The results show that Ti-Si-C powders were transformed to Ti, Si and little TiSi, SiC,Ti5Si3 intermetallics by milled for 18 hours. In this process, the little Ti and C transformed to TiSi phase in early stage, and then the most of residual elements reacted to form SiC and Ti5Si3 intermetallics. Finally, Ti, Si, SiC, Ti5Si3 intermetallics and TiSi reacted to yield Ti3SiC2 by hot pressing sintering. And the sintering temperatures had a significant impact on the yielded content of Ti3SiC2 phase. Besides. The Ti3SiC2 would decompose if the temperature was high enough.

Effect of Aluminum on Fabrication of Ti<sub>3</sub>SiC<sub>2</sub> by Mechanical Alloying and Spark Plasma Sintering

In the present study, we fabricated high purity and electrically machinable Ti3SiC2 ceramics by mechanical alloying and subsequent spark plasma sintering. The effect of a trace amount of Al on these synthesis processes was examined. Our results showed that Ti3SiC2 could be synthesized by high energy milling. Spark plasma sintering of mechanically alloyed powder at the temperatures of 1000-1200°C produced nearly single-phased Ti3SiC2 materials. The purity of the sintered Ti3SiC2 bulk was remarkably increased by addition of a small amount of Al. Ti3SiC2 with a purity of 99.3 wt% and a relative density of 98.9% was obtained by mechanical alloying and subsequent spark plasma sintering from a starting mixture composed of n(Ti) : n(Si) : n(Al) : n(c) = 3 : 1 : 0.2 : 2 at 1100°C.

Evaluating high-temperature modulus and elastic recovery of Ti3SiC2 and Ti3AlC2 ceramics

Elastic modulus and elastic recovery of both Ti3SiC2 and Ti3AlC2 at various temperatures were evaluated using cyclic loading–unloading in three-point bending tests and comparing relative slopes. It was found that the elastic moduli of Ti3SiC2 and Ti3AlC2, 310 and 288 GPa, were nearly constants in the temperature range from 20 to 1000 °C and then dramatically declined with further increasing of temperature. Elastic recovery as a function of temperature exhibited quite similar curve as the elastic modulus. The simple testing method was demonstrated convenient for estimating the elastic modulus and plastic deformation of ceramics at high temperature.