The influence of different SPS‐based methods, that is, conventional spark plasma sintering (SPS), flash SPS (FSPS), and reactive SPS (RSPS) on the properties of Al2O3/SiC composite was investigated. It was shown that the application of preliminary high energy ball milling of the powders significantly enhances the sinterability of the ceramics. It was also demonstrated that FSPS provides unique conditions for rapid, that is, less than a minute, consolidation of refractory ceramics. The Al2O3‐20 wt% SiC composite produced by FSPS possesses the highest relative density (~99%), fracture toughness (7.5 MPa m1/2), hardness (20.3 GPa) and wear resistance among all ceramics produced by other SPS‐based approaches with dwelling time 10 minutes. The RSPS ceramics hold the highest Young's modulus (390 GPa). Substitution of micron‐sized Al2O3 particles by nano alumina does not lead to measurable enhancement of the mechanical properties.
In this work, the possibility of the application of binders based on the polyvinyl alcohol and paraffin instead of environmentally-dangerous phenol-formaldehyde resin-based binders in the production of silicon carbide ceramics are investigated. Introduction of citric acid and carbamide in the binder based on water solution of polyvinyl alcohol ensures the high wettability of the powders of non-oxide ceramics by the binder. The addition of castor oil and oleic acid in the solution of paraffine in petroleum leads to a decrease in the inter-particles frictions and an increase in the density of green compacts. The developed binders allow to reduce compaction pressure by 12–15%.
Ceramic nanocomposites of silicon carbide reinforced Al2O3 are obtained by electroconsolidation. Mechanical properties are investigated and their dependencies on the composition and consolidation modes are shown over a wide range. The optimal composition and modes of electrical consolidation for the Al2O3-SiC composite are revealed. A criterion for choosing a material for instrumental application, which takes into account the basic properties of the cutting tool, is proposed. Comparison of the obtained composites with similar materials used for the manufacture of tool products including global manufacturers has been carried out.
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