摘要
TiN- Al2O3 composite powders with different TiN contents （0, 10 vol%, 20 vol%, 30 vol% and 40 vol% ）were prepared with micrometer TiN and α-Al2O3 powder （ their purities were 99% ） as starting materials by wet ball milling for 5 h. TiN-Al2O3 composite were then prepared by pressing the above composite powders, drying at 200 ℃ for 12 h and firing at 1 800 ℃ for 3 h in nitrogen atmosphere in hot-pressing furnace. The influences of TiN content on mechanical properties and electrical conductivity of TiN -Al2O3 composites were studied. The results showed that the mechanical properties of the composite increased with TiN content increasing, while the resistivity of composites decreased. A composite with 40% TiN had 498 MPa ben- ding strength, 4. 285 MPa· m1/2 fracture toughness, 1.34×10^-3 Ω· cm resistivity. The SEM analysis showed that the fine TiN crystals distributed among the crystal boundary of Al2O3 matrix. They bonded together forming a net-like structure which played a role of restraining Al2O3 grains from growing up, toughening and strengthening, so the mechanical properties of TiN -Al2O3 composite were enhanced.
TiN- Al2O3 composite powders with different TiN contents （0, 10 vol%, 20 vol%, 30 vol% and 40 vol% ）were prepared with micrometer TiN and α-Al2O3 powder （ their purities were 99% ） as starting materials by wet ball milling for 5 h. TiN-Al2O3 composite were then prepared by pressing the above composite powders, drying at 200 ℃ for 12 h and firing at 1 800 ℃ for 3 h in nitrogen atmosphere in hot-pressing furnace. The influences of TiN content on mechanical properties and electrical conductivity of TiN -Al2O3 composites were studied. The results showed that the mechanical properties of the composite increased with TiN content increasing, while the resistivity of composites decreased. A composite with 40% TiN had 498 MPa ben- ding strength, 4. 285 MPa· m1/2 fracture toughness, 1.34×10^-3 Ω· cm resistivity. The SEM analysis showed that the fine TiN crystals distributed among the crystal boundary of Al2O3 matrix. They bonded together forming a net-like structure which played a role of restraining Al2O3 grains from growing up, toughening and strengthening, so the mechanical properties of TiN -Al2O3 composite were enhanced.
