Characterization of Spark Plasma Sintered SiAlONTiCN Nano Composites

Abstract

Nano size starting powder mixtures like Silicon dioxide, Aluminium Nitride, Aluminium Oxide, Silicon Nitride and TiCN along with metallic oxide (CaO) as a charge stabilizer were used for the preparation of different sialon samples. To achieve homogeneous mixing of the powders, probe sonication was employed. After that spark plasma sintering of the samples was done at 1500o C for 30 minutes. Chemical composition of the samples (based on the general formula of αsialon i.e., Mx +vSi12-(m + n)Al(m+n)OnN16-n) was utilized in the present study represented by m and n values of 1.0 and 1.6 and m and n values of 1.1 and 0.6 along with TiCN reinforcements (10,20,30 wt%). The present study examined the densification behavior, phases, microstructure, and mechanical and thermal properties of synthesized SiAlON samples. It also correlates the effect of TiCN reinforcements on the physical, mechanical, thermal, and structural behavior of SiAlON-TiCN composites. Due to the localized heating mechanism provided by spark plasma sintering and also the high reactivity of nano-size powder mixtures resulted in near full densified SiAlON ceramics with relative density in the range of 98.04-93.42%. The hardness and fracture toughness values were in the range of 19.4-14.3 GPa and 5.8-2.9 MPa.m1/2 and were both influenced by level of densification. Highest hardness value of sample (1016-10TiCN) was found i.e., 19.4 GPa primarily due to the high oxide content. Highest fracture toughness value of sample (1016-10TiCN) was found i.e., 5.8 MPa.m1/2. Thermal conductivity values were seen to increase with increase in TiCN reinforcements with sample (1106-30TiCN) having highest thermal conductivity i.e., 9.69 W/mK and sample (1016-Pure) having lowest thermal conductivity i.e., 6.79 W/mK.