The oxidation behavior for ZrB2–20 vol% SiC (ZS20) and ZrB2–30 vol% SiC (ZS30) ceramics at 1500 °C was evaluated by weight gain measurements and cross-sectional microstructure analysis. Based on the oxidation results, laminated ZrB2–30 vol% SiC (ZS30)/ZrB2–25 vol% SiC (ZS25)/ZrB2–30 vol% SiC (ZS30) symmetric structure with ZS30 as the outer layer were prepared. The influence of thermal residual stress and the layer thickness ratio of outer and inner layer on the mechanical properties of ZS30/ZS25/ZS30 composites were studied. It was found that higher surface compressive stress resulted in higher flexural strength. The fracture toughness of ZS30/ZS25/ZS30 laminates was found to reach to 10.73 MPa m1/2 at the layer thickness ratio of 0.5, which was almost 2 times that of ZS30 monolithic ceramics.

An ordered dental enamel-like structure of hydroxyapatite (HAp) was achieved through a solution mediated solid-state conversion process with organic phosphate surfactant and gelatin as the mediating agent. Transmission electron microscopy (TEM) tests demonstrated uniform sizes in the obtained apatite nanorods which arranged in parallel to each other along the c-axis and formed organized microarchitectural units over 10 μm in size. The sizes of the synthetic hydroxyapatite nanorods were similar to that observed in enamel from human teeth. The formation and regulation of the orientation and size of HAp nanorods might lead to a better understanding of the biomineralization process for the preparation of high performance biomaterials.

The (Al2O3 + Ni) composite, (Al2O3 + Ni)/Ni and Al2O3/(Al2O3 + Ni)/Ni laminated materials were prepared by aqueous tape casting and hot pressing. Results indicated that the (Al2O3 + Ni) composite had higher strength and fracture toughness than those of pure Al2O3. The fracture toughness of (Al2O3 + Ni)/Ni and Al2O3/(Al2O3 + Ni)/Ni laminated materials was higher than not only those of pure Al2O3, but also those of Al2O3/Ni laminar with the same layer numbers and thickness ratio. It was found that the toughness of the Al2O3/(Al2O3 + Ni)/Ni laminated material with five layers and layer thickness ratio = 2 could reach 16.10 MPa m1/2, which were about 4.6 times of pure Al2O3. The strength and toughness of the (Al2O3 + Ni)/Ni laminated material with three layers and layer thickness ratio = 2 could reach 417.41 MPa and 12.42 MPa m1/2. It indicated the material had better mechanical property.

Gelcasting is an attractive forming process to fabricate ceramic parts with complex shape. In the present work, aqueous gelcasting of SiC was studied. SiC slurry (50 vol.%) for gelcasting was prepared with sintering assistants, Al2O3 and Y2O3. The slurry was solidified in situ to green body with relative density of 55.9 ± 0.9% and flexural strength of 13.9 ± 0.7 MPa. SEM shows that ceramic powders in green body compact closely by the connection of polymer networks, and that the pores decrease greatly with the size less than 1 μm. SiC samples were also obtained by the process of gelcasting and pressureless sintering at 2000 °C for 1 h in Ar atmosphere. The relative density and flexural strength of SiC sintered body are 97.3 ± 0.4% and 637 ± 156 MPa, and the hardness and toughness are 20.68 ± 0.80 GPa and 3.85 ± 0.23 MPa m1/2, respectively.

In this work commercial polyurethane sponges with open porosity of approximately 13 pores per inch were chosen as the templates to produce the SiC RPCs. Effects of the rheological behavior of the slurry on the coating quality and the properties of SiC RPCs such as strength, density, microstructure, were investigated in detail. The coating quality was found to depend strongly on the slurry viscosity and this was improved dramatically extremely as the viscosity increased. The SiC RPCs displayed a remarkable increase in the flexural strength as the solids content increased. In addition, the increase of the polymer content had also a little contribution to the improvement of the strength The optimum solids content and polymer content were found to be 80 and 0.20 wt.%. This study shows that the control of slurry rheology is very important for the processing of RPCs.