Development of Dense and Hard Materials Based on Oxide – Non-Oxide Compounds with Added Intermetallic Components During Spark Plasma Sintering

The paper shows the effect of Ti 2 AlNb, NiTi, NiNbZr, and NiVTa additives during spark plasma sintering of the compositions under a pressing loading of 60 MPa in the temperature range from 1200 to 1600°C on the phase composition, microstructure, grain sizes of the crystalline phases, relative density, linear shrinkage, physical and mechanical properties, linear correlation of the modulus of elasticity, and fracture toughness of the mullite—(Ti,Mo)(C,N) – c -ZrO 2 – c -BN and mullite – (Ti,Mo)(C,N) – β-Si 3 N 4 – c -BN samples. Synthesized powders of Ti(C 0.7 N 0.3 ), β-Si 3 N 4 , c -BN, Ti 2 AlNb, NiTi, NiNbZr, and NiVTa show intensive crystallization of Ti(C 0.7 N 0.3 ), β-Si 3 N 4 , c -BN, Ti 2 AlNb, NiTi, Ni 45 Nb 35 Zr 20 , and Ni 17 V 61 Ta 22 phases. Spark plasma sintered c -ZrO 2 (at 1400°C) and (Ti,Mo)(C,N) (at 1800°C) show intensive crystallization of c -ZrO 2 and (Ti 0.7 Mo 0.3 )(C 0.7 N 0.3 ) phases. The crystalline microstructure of the sintered c -ZrO 2 and (Ti,Mo)(C,N) phases consists of variously sintered and compacted grains of different shapes. The Ti 2 AlNb, NiTi, NiNbZr, and NiVTa additives contribute to different crystallization of mullite and (Ti,Mo)(C,N), ZrO 2 , β-Si 3 N 4 , and c -BN phases in the temperature range from 1200 to 1600°C. Crystallization of the NiTi phase proceeds more intensively compared to the Ti 2 AlNb phase, and samples sintered in the temperature range from 1400 to 1600°C demonstrate higher crystallinity of the Ni(Zr,Nb), Ni 45 Nb 35 Zr 20 , Ni(Ta,V), and Ni 17 V 61 Ta 22 phases. The NiTi and NiVTa additives enhance sintering and promote the formation of more uniform and densely sintered microstructures of the samples at 1500°C, which results in polydisperse grain compositions of the crystalline phases of the samples in the range from 1200 to 1600°C. Samples containing the NiTi and NiVTa additives show a more active increase and higher physical and mechanical properties, crack resistance, linear correlation of the modulus of elasticity, and fracture toughness in the range from 1200 to 1600°C.