Fine-grained (Ti-Zr-Nb-Ta-Hf)C/(Ti-Zr-Nb-Ta-Hf)B2 dual-phase high-entropy boride/carbide ceramic (HEC/HEB) was prepared from powders synthesized via a boro-carbothermal reduction and sintered by spark plasma sintering. The developed ceramic has a very high density and relatively homogeneous chemical composition of HEC and HEB grains with a size of HEC grains from 0.1 μm to 1.5 μm and HEB grains from 0.1 μm to 5 μm. The microstructure and damage/fracture characteristics were studied using scanning electron microscopy (ZEISS AURIGA) and EDX analyses. The mechanical properties of the HEC/HEB system were characterised by measuring their nano/micro/macro hardness and indentation fracture resistance using indentation methods. Nanoindentation was carried out using a Berkovich diamond tip applying continuous stiffness measuring (CSM) mode with a maximum depth of 150 nm. Indents were prepared, arranged in 10×10 arrays with a distance between the indents of 6 μm. The nanohardness of the HEC and HEB grains are very high with values of 37.4 ± 2.3 GPa and 43.3 ± 2.9 GPa, respectively. The Young’s modulus of HEC with a mean value of 536.5 ± 34.2 GPa is significantly lower in comparison to Young’s modulus for HEB grain with a mean value of 766 ± 45.7 GPa. Macro-hardness was measured by Vickers under a load of 9.8 N and 29.4 N with a dwell time of 10 s. In order to determine the indentation fracture resistance, 10 Vickers imprints per specimen were introduced with an applied load of 29.4 N, held for 10 s. Vickers hardness HV1 of the developed HEC/HEB ceramic is very high with a value of 29.4 ± 2.0 GPa which is the highest between the up-to-now reported dual-phase high-entropy ceramics. The developed system shows good indentation fracture resistance with a value of 3.9 ± 0.62 MPa·m1/2. The most significant toughening mechanism is crack branching in larger HEC grains with sizes from 1.0 μm to 1.5 μm.                                                                                       
The wear characteristics were studied using ball-on-flat technique/dry sliding in air with SiC ball as tribological partner at applied loads 5 N, 25 N and 50 N with total sliding distance and sliding velocity 500 m and 0.1m/s. The deformation and damage characteristics were studied using scanning electron microscopy + EDAX and confocal electron microscopy. The friction coefficient values during the test were very similar, 0.57 in case of 5 N and 0.6 in the case of applied load 25 N and 50 N. The specific wear rate slightly decreased with increasing applied load from 5 N to 25 N from 7.9.10-7 mm3/Nm to 6.6.10-7 mm3/Nm and increased at applied load of 50 N to 9.1.10-6 mm3/Nm. The dominant wear mechanisms in all cases were tribochemical reaction and tribo-layer formation.