Arc-shaped integrated alumina ceramic armor for body bulletproof with the size of 300 × 250 × 6 mm, R400mm were prepared by semi-aqueous gel-casting. The excellent characters and advantages of the semi-aqueous gel-casting were analyzed; ballistic experiments were carried out to test the protection coefficient of 92%, 96%and 99 alumina ceramics. The experimental results showed that the 92% alumina ceramic and the 99% alumina ceramic had favorable performance while the 96% alumina ceramic had the worst one. But the 92% alumina ceramic had the highest protection coefficient which is 9.96.
Barium strontium titanate/magnesium oxide composite ceramic plates were prepared by non-aqueous gel-casting using barium strontium titanate and MgO as the raw materials. The rheological properties of the non-aqueous slurries, the dosages of the catalyst and initiator, micro structures and phase structures of the sintering ceramic plates were investigated and analyzed. The results showed that the slurry with solid content of 50wt% in non-aqueous gel-casting had excellent rheological properties and operating characteristics. Ba0.6Sr0.4TiO3/MgO plates with a smooth surface and dense structure were fabricated through desiccation and sintering at 1300°C, and the relative density is up to 4.14g/cm3. The polished surface of the ceramic substrate was composed of 35% MgO and 65% Ba0.6Sr0.4TiO3, and the content of Ba0.6Sr0.4TiO3 was obviously higher compared to the content in the raw materials which was explained by the phenomena of surface phase enrichment.
A process is adopted to grow whiskers on carbon fibers. The whisker growth is carried out in a two-step process. Plasma spraying, electroplating and magnetron sputtering are used to pretreat the surface of carbon fibers and then ZnO whiskers are grown by hydrothermal method. By comparing three different methods of surface pretreatment, it is concluded that magnetron sputtering is most available and has no damage to the carbon fibers. Combining preparation method of the ZnO whiskers, a new process is developed to surface modified of carbon fibers which is expected apply to carbon fiber composites.
BaTiO3ceramic composite powders were prepared by a gel-solid reaction method using the raw materials of two particle sizes, DSC was used to study the thermal decomposition of the green body. The effect of the calcination temperatures on the phase structure of the powders was investigated. The influence of the particle sizes of the raw materials on the reaction temperature and the microstructure of the powders was explored. The results showed that reaction temperature of BaTiO3ceramic powders reacted from BaCO3of the large size was about 933.0°C, and the one from BaCO3of the smaller size was about 903.5°C, respectively. XRD results indicated that BaTiO3powders could be prepared at a temperature range of 900°C ~ 1000°C using the raw materials of either size. The particle size of the synthesized powders was determined by the particle size of the raw material. Therefore, the raw materials of small size should be chosen to prepare the synthesized powders of small size, and at a lower reaction temperature.
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