The preparation technology of nano ceramics is an effective means to improve the brittleness and toughness of ceramics. Composite technology and sintering process are important for the preparation of nano ceramics. The uniform dispersion of nano ceramic composite powder is the prerequisite for the preparation of nano ceramics. At present, the most widely applied dispersion and composite technology mainly include liquid phase mixing and chemical wrapping. Advanced sintering technologies, such as spark plasma sintering, hot pressing sintering, oscillating pressure sintering, two-step sintering and hot isostatic pressing sintering, are often used to inhibit grain growth. The development progress, classification and toughening mechanism of nano ceramics are reviewed. With selected examples, the dispersion and sintering technology are summarized. Meanwhile, the microstructure and properties of nano ceramics prepared by different dispersion and sintering technologies are analyzed and overved.

Silicon nitride ceramics have become the most promising advanced ceramic materials, because of their excellent mechanical, thermal and biological properties. The key sintering technologies of silicon nitride ceramics are discussed, while the principle, advantages and disadvantages of various sintering technologies are analyzed. With considering the latest development of silicon nitride ceramic materials, their latest applications, as high strength and toughness structural ceramics, high thermal conductivity and wave permeability ceramics, and good biocompatibility of bioceramics in aerospace, national defense, semiconductor packaging, biomedicine and other fields, are reviewed.

High temperature superplastic ceramics or ceramic high temperature superplasticity means that polycrystalline ceramic materials exhibit high elongation ability at high temperatures at under applied stresses without necking or cavities during tensile process. The maximum tensile superplastic deformation rate of ceramics with fine grain microstructure can reach 1053%. A large number of studies indicated that, in addition to tensile or compression deformation, ceramics can also achieve a specific shape similar to that of metals. Generally, grain boundary slip is considered to be the mechanism of ceramic superplasticity, while dislocation slip and creep also play an important role. The development and mechanism of superplastic ceramics are summarized. The superplastic properties and variation of oxide, non-oxide and various composite ceramics have been discussed. The tensile and compression deformation capacities of these ceramics under different conditions are summarized.

ATZ ceramics (20 wt.% Al₂O₃ + 80 wt.% 3Y-ZrO₂) have excellent room temperature mechanical strength, high temperature mechanical properties and strong hydrothermal aging resistance. ATZ ceramics with high strength and hardness were prepared by using spark plasma sintering. The densification process and strengthening and toughening mechanism were deeply studied. The ATZ ceramics have few defects due to the action of the pressure and electricity. The optimized sample, with sintering temperature of 1450 ℃ and grain size of 298 nm, exhibited bending strength and Vickers hardness of as high as 1767 MPa and 14.5 GPa, respectively. Both high-density semi-coherent grain boundary and coherent grain boundary were observed, according to the transmission electron microscopy (TEM) images. The special grain boundary structure and fine grain are responsible for the high strength and high hardness of the ATZ ceramics.

In this work, various backbone binders were used in wax-based binder system to formulate zirconia parts by ceramic injection molding (CIM). The effect of different backbone binders on the molding, debinding, and sintering behaviors was investigated. After blending process, the feedstock using multi-polymer components exhibited more homogeneous structure compared with that using the mono-polymer ones due to the synergistic effect of multi-polymers. During solvent debinding, some defects such as “slumping” and “peeling” appeared in the parts containing ethylene-vinyl acetate copolymer (EVA), but they were not found in the parts with other thermal polymers. Also, as for the parts after sintering, the one using low density polyethylene (LDPE) and high density polyethylene (HDPE) as backbone binders presented a more uniform microstructure with finer zirconia grains among all the investigated compositions, and thus obtained the highest flexural strength (~949 MPa) and relative density (~98.9%).