Ming Hao Fang

Micromorphologies and Defects in CVD ZnS and ZnSe

ZnS and ZnSe for infrared optical windows were fabricated by particular Chemical Vapor Deposition (CVD) process with so-called S method and Se method respectively. Their morphology and defects are reported in this paper. The microstructure, composition and the influence on optical properties of the defects were investigated. The process reasons leading to these defects were discussed as well. Hot isostatic pressing (HIP) treatment was adopted to eliminate some of the defects, and the effect of HIP on optical properties was evaluated.

Low Temperature Synthesis of Strontium Barium Niobate by Spark Plasma Sintering

Pure Strontium barium niobate, Sr0.5Ba0.5Nb2O6 (SBN50), was synthesized successfully by spark plasma sintering from two mixtures: SrCO3/BaCO3/Nb2O5 mixtures and the mixtures calcined at 800oC. The phase identification of the SBN crystalline grains was evaluated by X-ray diffraction analysis, and the formation mechanism was discussion based on the XRD results at various temperatures. They are different when SrCO3/BaCO3/Nb2O5 powder mixtures and the mixtures calcined at 800oC was chosen as the raw materials.

Preparation of Wear-Resistant Ceramics with Tangshan Ironstone-Tailings

Wear-resistant ceramics were prepared successfully with Tangshan Ironstone-tailings. The effects of additives and sintering temperature on their mechanical property were studied. The erosive wear performance of ceramics was evaluated in liquid-solid flow. The erosive wear mechanism was also analyzed. The results showed that the wear-resistant ceramic prepared at 1200°C using 50wt% Tangshan Ironstone-tailings 10wt%, mild-clay and 40wt% high aluminum fly ash as the starting materials had high strength and good erosive wear resistance. The erosive wear mechanisms were washout particles’ micro-cutting and liquid washing.

Fabrication and Mechanical Properties of HAp/Ti3SiC2 (60 vol.%) Composite by Sparkle Plasma Sintering

HAp-Ti3SiC2 (60 vol.%) composite was fabricated using Sparkle Plasma Sintering (SPS). The mechanical properties and microstructure of the composite sintered at different temperature were investigated. The results show that no reaction occurred between HAp and Ti3SiC2, and the strength and fracture toughness of the composite were improved relative to pure HAp, which may be attributed to the change of microstructure and fracture mode as an effect of Ti3SiC2 addition.

Properties of Na1/2Bi1/2TiO3 Ceramic Prepared by Sol-Gel Method

Bismuth sodium titanate ceramic was prepared by sol-gel method. The crystallization, density and microstructure were determined. The grains of BNT ceramic prepared by sol-gel method were equiaxial, ~ 2 µm, which was smaller than that prepared by solid-state reaction method. The piezoelectric and dielectric properties were investigated. When the sintering temperature was 1140°C, maximum relative dielectric constant and piezoelectric constant can be obtained. The piezoelectric constant of BNT ceramic prepared by sol-gel method was higher than those prepared by solid-state reaction method.