Study Of The Sintering Parameters And Properties Of TiBCN Composite Materials Prepared By Spark Plasma Sintering

TiB2 and TiCN ceramic materials have been applied in many fields for their excellent physical and chemical properties such as better thermal stability, wear resistance and higher hardness. However improving its mechanical properties has been followed especially toughness property. The group prepared TiBCN powder with boronizing, the compacted powders were sintered by spark plasma sintering, and the microstructure and properties of ceramic were investigated. In order to decrease TiBCN ceramic sintering temperature and increase the density and the mechanical properties of the sintered material,(8% wt) Ni,(7% wt) Mo, and(15% wt) WC were added by mechanical mixing, therefore,the compact TiBCN composite ceramic were obtained.In the study, spark plasma sintering technology parameters, TiBCN ceramic powder sintering temperatures were 1250℃, 1350℃, 1450℃. Sintering pressure were 40 MPa,45MPa, 50 MPa. Sintering holding time were 3min, 5min, 8min. Heating rate were 80℃/min, 90℃/min, 100℃/min. The sintering parameters of TiBCN based composite material:sintering pressure was 50 MPa, holding time was 5min, heating rate was 90 ℃ /min,sintering temperatures were 1000℃, 1100℃, 1200℃, respectively. The microstructure of polished specimens and fracture section were observed by SEM. Phases identification was carried out by X-ray diffraction(XRD). The density of the samples was measured by using Archimede method. The Rockwell hardness(HRA) was performed on polished surfaces.The flexural strength and fracture toughness were measured by three-point bending method on the Universal Testing Machine.Results showed that the density, hardness, flexural strength increased with increasing sintering temperature. The performances of TiBCN ceramic materials were comparatively better when the sintering temperature was 1450℃. The density, hardness flexural strength and fracture toughness were 97.10%, 75.3HRA, 325.07 MPa, 5.059 MPa·m1/2, respectively.The density of TiBCN ceramic had greatly improved with raising sintering pressure from40 MPa to 50 MPa, which was 97.10%. Sintering holding time had no significant influence on the density and hardness. The flexural strength gradually reduced as the heating rate increased, which was 362.5MPa at a heating rate of 80 ℃ /min. While the density and hardness changed gently, the density reached over 91.00%, and hardness were separately70.6, 75.3, 69.3. When the sintering temperature was 1450 ℃, sintering pressure was50 MPa, holding time was 5min, heating rate was 90 ℃ /min, the TiBCN composite properties were relatively better.Results of the TiBCN composite materials showed that the density and mechanicalproperties had been significantly improved. The density, hardness, flexural strength and fracture toughness were 98.91%, 88.2HRA, 396.19 MPa, 6.025 MPa·m1/2 at the sintering temperature 1100 ℃ and holding pressure 50 MPa. The sintering temperature reduced about 350℃ comparing with the same density of pure TiBCN ceramic material. At same sintering condition, the density of TiBCN composite ceramic materials increased 1.87%,and hardness, flexural strength, fracture toughness increased 17.13%, 21.87%, 19.10%,respectively.