Preparation of Ti-Al-N-O Ceramics by Mechanical Alloying and Spark Plasma Sintering

Ti1-x-Al-x-N-O powders, with Al content in metallic elements (x= x(Al)/x(Ti)+x(Al)) ranging from 0 to 0.4, were synthesized from TiN and Al2O3 powders using mechanical alloying. Densification of these original powders is carried out by the spark plasma sintering is performed at 50 MPa and up to 1300 degrees C. From the result of X-ray diffraction (XRD) and transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS), it was confirmed that (Ti,Al) (N,O) phase with NaCl structure was synthesized from the Ti1-x-Al-x-N-O powder with x = 0.2. However, XRD results indicated that crystal phase of sintered bodies was TiN-Al2O3 composite. The theoretical densities of sintered bodies were increase from 95.6% to 99.6% with increasing of x in the range from 0 to 0.4. Furthermore, the Ti1-x-Al-x-N-O ceramics with x = 0.3 and 0.1 exhibited maximum Vickers hardness of HV2230 and maximum fracture toughness of 5.5 MPa.m(1/2), respectively.