Densification, microstructure and properties of TiB2 ceramics fabricated by spark plasma sintering

Balcı, Özge; Burkhardt, Ulrich; Schmidt, Marcus; Hennicke, J.; Yağcı, M. Barış; Somer, M.

doi:10.1016/j.matchar.2018.09.010

Cited by 30 publications

(12 citation statements)

References 43 publications

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“…The powder mixture composition, sintering parameters and relative density values of the obtained materials are shown in Table 1 and compared to the TiB 2 sinter produced by SPS at 1700 °C. The relative density of the TiB 2 sinter is low in comparison to those in References [ 4 , 12 ]. This sinter was produced using the same TiB 2 powder and in the same sintering conditions as the composites and was used as the referential sample.…”

Section: Resultscontrasting

confidence: 54%

“…The anisotropy of its thermal expansion coefficient is believed to be a source of microcrack formation and brittleness, observed either at the synthesis stage of TiB 2 or thermal cycles taking place afterward both in bulk materials and thin films [ 3 ]. A low self-diffusion coefficient and an extremely high melting point make it difficult to obtain TiB 2 sinters of high density [ 4 , 5 ]. Among the different sintering methods, the most effective and fastest is spark plasma sintering (SPS).…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Properties of TiB2 Composites Produced by Spark Plasma Sintering with the Addition of Ti5Si3

et al. 2021

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Titanium diboride (TiB2) is a hard, refractory material, attractive for a number of applications, including wear-resistant machine parts and tools, but it is difficult to densify. The spark plasma sintering (SPS) method allows producing TiB2-based composites of high density with different sintering aids, among them titanium silicides. In this paper, Ti5Si3 is used as a sintering aid for the sintering of TiB2/10 wt % Ti5Si3 and TiB2/20 wt % Ti5Si3 composites at 1600 °C and 1700 °C for 10 min. The phase composition of the initial powders and produced composites was analyzed by the X-ray diffraction method using CuKα radiation. The microstructure was examined using scanning electron microscopy, accompanied by energy-dispersive spectroscopy (EDS). The hardness was determined using a diamond indenter of Vickers geometry loaded at 9.81 N. Friction–wear properties were tested in the dry sliding test in a ball-on-disc configuration, using WC as a counterpart material. The major phases present in the TiB2/Ti5Si3 composites were TiB2 and Ti5Si3. Traces of TiC were also identified. The hardness of the TiB2/Ti5Si3 composites was in the range of 1860–2056 HV1 and decreased with Ti5Si3 content, as well as the specific wear rate Wv. The coefficient of friction for the composites was in the range of 0.5–0.54, almost the same as for TiB2 sinters. The main mechanism of wear was abrasive.

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Section: Resultscontrasting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Microstructure and Properties of TiB2 Composites Produced by Spark Plasma Sintering with the Addition of Ti5Si3

et al. 2021

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“…To achieve good densification without using sintering additives, temperatures above (2000 • C) were used. Extensive grain growth at high temperatures has been reported before and is typical for boride materials [36,37]. The good densification of the cathode resulted in higher room-temperature conductivity (compared to the other cathodes produced) and significantly lower dependence of conductivity on temperature.…”

Section: Tib 2 -Csupporting

confidence: 56%

“…The high abundance of particles seen during the arc evaporation is typically associated with a material having a low melting point [30]. Since TiB 2 has a high melting point (~3500 K) [37], it is expected to produce an insignificant number of droplets. However, once the arc is triggered, extensive particle emission can be observed visually as a glowing spark, and these are also found around the chamber after deposition.…”

Section: Tib 2 -Tisimentioning

confidence: 99%

Facilitating TiB2 for Filtered Vacuum Cathodic Arc Evaporation

et al. 2020

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TiB2 is well established as a superhard coating with a high melting point and a low coefficient of friction. The brittle nature of borides means they cannot be utilised with arc evaporation, which is commonly used for the synthesis of hard coatings as it provides a high deposition rate, fully ionised plasma and good adhesion. In this work, TiB2 conical cathodes with non-standard sintering additives (carbon and TiSi2) were produced, and the properties of the base material, such as grain structure, hardness, electrical resistivity and composition, were compared to those of monolithic TiB2. The dependence of the produced cathodes’ electrical resistivity on temperature was evaluated in a furnace with an argon atmosphere. Their arc–evaporation suitability was assessed in terms of arc mobility and stability by visual inspection and by measurements of plasma electrical potential. In addition, shaping the cathode into a cone allowed investigation of the influence of an axial magnetic field on the arc spot. The produced cathodes have a bulk hardness of 23–24 GPa. It has been found that adding 1 wt% of C ensured exceptional arc-spot stability and mobility, and requires lower arc current compared to monolithic TiB2. However, poor cathode utilization has been achieved due to the steady generation of cathode flakes. The TiB2 cathode containing 5 wt% of TiSi2 provided the best balance between arc-spot behaviour and cathode utilisation. Preventing cathode overheating has been identified as a main factor to allow high deposition rate (±1.2 µm/h) from TiB2-C and TiB2-TiSi2 cathodes.

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“…[48] After sublimation, the ceramic substrate is sintered for the structural consolidation. [49,50] The resultant substrate is generally characterized by an aligned and connected pore structure while achieving low pore tortuosity. [51] The solvent plays an important role as structuring and pore forming agent and each solvent results in a particular pore shape.…”

mentioning

confidence: 99%

Manufacture of Highly Porous Tubular Alumina Substrates with Anisotropic Pore Structure by Freeze‐Casting

et al. 2020

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Porous substrates play a major role in devices requiring the flow of fluids such as in filters and membranes. Porous substrates are also extensively used for the preparation of inorganic membranes for microfiltration, [1][2][3] desalination, [4][5][6][7] gas separation, [8][9][10][11] and percrystallization processes. [12,13] These inorganic membranes are known as asymmetric membranes as they are conventionally prepared by coating ceramic [14][15][16] or carbon [17][18][19] thin films as top layers on porous substrates. The importance of the porous substrate is to provide the mechanical strength otherwise not available in thin films. Many inorganic materials such as ceramics [20][21][22] and stainless steel [23][24][25] have been manufactured as porous substrates, though alumina is the most used material due to lower costs and processing versatility. Porous substrates come in several geometries such as tubes, [14,[26][27][28] hollow fibers, [29][30][31] and flat surfaces. [19,32] Traditionally, inorganic porous substrates are prepared from conventional ceramic processes such as slip-casting, [33,34] extrusion, [35,36] dry pressing, [37] tapecasting, [38][39][40] and phase inversion hollow fibers. [41,42] A relatively more recent method is the freeze-casting technique for processing porous ceramic substrates. [43][44][45][46] Due to the ability of forming an aligned pore structure, this technique can overcome problems associated with lower fluid fluxes conferred by conventional ceramic processing methods such as tortuous pore structure, constrictions, and dead-end and isolated pores. [47] Freeze-cast starts with the preparation of a stable ceramic suspension (or slurry) at normal conditions followed by controlled freezing of the solvent of the ceramic

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Densification, microstructure and properties of TiB2 ceramics fabricated by spark plasma sintering

Cited by 30 publications

References 43 publications

Microstructure and Properties of TiB2 Composites Produced by Spark Plasma Sintering with the Addition of Ti5Si3

Microstructure and Properties of TiB2 Composites Produced by Spark Plasma Sintering with the Addition of Ti5Si3

Facilitating TiB2 for Filtered Vacuum Cathodic Arc Evaporation

Manufacture of Highly Porous Tubular Alumina Substrates with Anisotropic Pore Structure by Freeze‐Casting

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