Nanostructured ceramic composite rods: Synthesis, properties and application

摘要

The nanostructured ceramic composites based on TiC-TiB2 have attracted a great interest during recent years because they exhibit superior properties combining high hardness and good wear resistance. Here we demonstrate the possibility of producing TiC-TiB2- ZrO2-Al2O3 based ceramic composites via self-propagating hightemperature synthesis by extrusion method (SHS-extrusion). The effect of reactant composition on the microstructure of obtained composites was studied. According to X-ray diffraction (XRD) the synthesized ceramic composites consist of TiC, TiB2, ZrO2 (monoclinic and tetragonal), and Al2O3 phases. ZrO2 and Al2O3 phases form eutectic consisting of extended filaments up to 100 nm in thickness and 2-3 mu m in length. TiC and TiB2 grains with sizes of 1-2 mu m surround the filaments. The composite materials were used as electrodes for electricspark deposition. The deposited coatings have high wear resistance (1 x 10(-5)mm(3)/N/m) and low friction coefficient (0.2).