Coarse‐Grained Refractory Composite Castables Based on Alumina and Niobium

Niobium-alumina composite aggregates with 60 vol% metal content and particle sizes up to 3150 μm are produced using castable technology followed by sintering, a crushing sieving process. X-Ray diffraction (XRD) analysis reveals phase separation during as the niobium:corundum volume ratios is between 37:57 64:31 among 4 aggregate classes 0–45, 45–500, 500–1000, 1000–3150 μm. The synthesized used produce coarse-grained refractory composites in second casting sintering step. fine- material shows porosities 32% 36% determined cold modulus of rupture 20 12 MPa, E-moduli 37 46 GPa, respectively. fine-grained reached true strain values 0.08 at 1100 °C 0.18 1500 ones 0.02 0.09. electrical conductivity for 448 ± 66 111 25 S cm−1,