Combustion synthesis of NbC/ZrO₂ composites: Influence of Cr additives on the microstructure and mechanical properties

Abstract

Composites of NbC/ZrO2 reinforced with different weight ratios of Cr metal were prepared by dynamic compaction combustion from a blend of Nb2O5–Zr–Cr powders. Factors controlling the synthesis process, the microstructure, and the mechanical properties of the samples, such as Cr wt% and the compression loads were studied. The samples were characterized by XRD, SEM, porosity, and hardness measurements. The porosity value of the sample with no additives was high and reached 31.6 vol%. A sudden decrease in the sample porosity to 2.4 vol % was noticed for the sample containing 3.0 wt% of Cr. A high‐density sample with less than 2.0 vol % porosity and maximum hardness of 1038 HV was produced using 5.0 wt% Cr under 300 MPa compression load. Detailed thermodynamic calculations for the effect of Cr additives on the physicochemical properties of the system were introduced.

Combustion Synthesis of High Density ZrN/ZrSi2 Composite: Influence of ZrO2 Addition on the Microstructure and Mechanical Properties

“…It could be noticed that additions of ZrO 2 led to a gradual decrease in the adiabatic temperature and the fraction of the total liquid phase. It is well known that the amount of liquid phase strongly controls the sample sintering [ 22 , 36 ]. Figure 5 simply shows that the increase in sample porosities with ZrO 2 addition was strongly related to the decrease in both the total liquid phase and adiabatic temperatures.…”

“…In this study, a composite of ZrN/ZrSi 2 /ZrO 2 will be synthesized from Zr, Si 3 N 4 , and ZrO 2 powders using combustion synthesis under load methodology [ 35 , 36 ] to obtain dense objects. The effects of ZrO 2 as an inert reinforcement and the application of different compression loads will be investigated.…”