The physical, mechanical, and thermal properties of polycrystalline TiB2 are examined with an emphasis on the significant dependence of the properties on the density and grain size of the material specimens. Using trend analysis, property relations, and interpolation methods, a coherent set of trend values for the properties of polycrystalline TiB2 is determined for a mass fraction of TiB2 98 %, a density of (4.50.1) g/cm 3 , and a mean grain size of (91) m.

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Material Properties of Titanium Diboride.

The correlation of pore morphology, interconnectivity and physical properties of 3D ceramic scaffolds with bone ingrowth.

Comparison of single and two-phase models for nanofluid convection at the entrance of a uniformly heated tube

Thermal shock resistance of cubic 8 mol% yttria-stabilized zirconia (YSZ) can be increased by the addition of dilute second phases. This study addresses how these dilute second phases affect the thermal conductivity for two-phase ceramic composites of 8 mol% YSZ with 10–20 vol% alumina (Al2O3) or 10–20 vol% mullite (3Al2O3·2SiO2). Thermal conductivity measurements from 310 K (37°C) to 475 K (202°C) were made using the 3ω method and compared with results from 3D analytical models and a 2D computational microstructure-based model (Object-Oriented Finite Element Analysis, OOF2). The linear Rule of Mixtures was the least accurate and significantly overestimated the measured thermal conductivity at low temperatures, with errors in some cases exceeding 100%. Calculations using the Bruggeman and OOF2 models were both much better, and the deviation of less than ±2.5% across all compositions and temperatures is within the range of experimental and modeling uncertainty. The Maxwell Garnett equation was a close third in accuracy (±8%). A sensitivity analysis for each model quantifies how small perturbations in the thermal conductivity of the dispersed second phase influence the effective thermal conductivity of the composite, and reveals that the linear Rule of Mixtures model is physically unrealistic and oversensitive to the thermal conductivity of the dispersed phase.

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Comparison of Two‐Phase Thermal Conductivity Models with Experiments on Dilute Ceramic Composites

Purpose




The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to rapidly shape ceramic parts with an almost unlimited shape freedom. In this paper, alumina (Al2O3) parts are produced, as Al2O3 is currently the most commonly used ceramic material for technical applications.




Design/methodology/approach




Variants of the following PM route, with indirect selective laser sintering (indirect SLS) as the AM shaping step, are explored to produce ceramic parts: powder synthesis, indirect SLS, binder removal and furnace sintering and alternative densification steps.




Findings




Freeform-shaped Al2O3 parts with densities up to approximately 90 per cent are obtained.




Research limitations/implications




The resulting Al2O3 parts contain inter-agglomerate pores. To produce higher-quality ceramic parts through indirect SLS, these pores should be avoided or eliminated.




Originality/value




The research is innovative in many ways. First, composite powders are produced using different powder production methods, such as temperature-induced phase separation and dispersion polymerization. Second, four different binder materials are investigated: polyamide (nylon-12), polystyrene, polypropylene and a carnauba wax – low-density polyethylene combination. Further, to produce ceramic parts with increased density, the following densification techniques are investigated as additional steps of the PM process: laser remelting, isostatic pressing and infiltration.

R. G. Munro

Papers

Evaluated Material Properties for a Sintered α‐Alumina