Entity

Time filter

Source Type


Li Q.,University of Jinan | Li Q.,Shandong Provincial Key Laboratory of Preparation and Measurement | Wu C.,University of Jinan | Wang Z.,University of Jinan
Journal of Alloys and Compounds | Year: 2015

Nano-Al2O3 particles reinforced Al2O3/AlN ceramic composite with high mechanical properties were fabricated by vacuum hot-pressing sintering at 1600 °C under an applied pressure of 30 MPa for 180 min. Compared with the blank sample, the sample with 20 vol.% Nano-Al2O3 addition had a significant improvement in mechanical properties, and the flexural strength, fracture toughness and relative density reached to 432.65 (±21.67) MPa, 5.26 (±0.89) MPa m1/2 and 99.3 (±0.21)%. It can be seen from the SEM images, EDS analysis and XRD patterns that Nano-Al2O3 particles agglomerate in the boundary to form sub-micron particles and react with AlN at grain boundary to form the solid solution of AlON. Moreover, the relationship of mechanical properties and microstructure transition of composite is illustrated by schematic and Zener's formula. © 2015 Elsevier B.V.


Wu C.,University of Jinan | Wang Z.,University of Jinan | Li Q.,University of Jinan | Li Q.,Shandong Provincial Key Laboratory of Preparation and Measurement | And 3 more authors.
Journal of Alloys and Compounds | Year: 2014

The composites with CeO2 addition varied from 0 vol.% to 5 vol.% were sintered at 1420 °C under an applied pressure of 30 MPa for 60 min. The results of mechanical tests showed that CeO2 is useful for improving mechanical properties, but excessive addition (>3 vol.%) will deteriorate the composite; The highest values of relative density, Vickers harness, flexural strength and fracture toughness were recorded for the sample with 3 vol.% addition, which produced 97.6%, 15.7 MPa, 406.5 MPa and 6.36 MPa m1/2. It can been seen from the SEM images and EDX analysis that the abnormal rod-like crystals appeared among Al2O3 grains. These unusual grains were confirmed as the solid solution of Ce-Al-O. The XRD revealed the crystalline phase and the transformation of grain growth trend of Ti/Al2O3 cermet composite. Moreover, the relationship of microstructure evolution and mechanical properties for the composite were illustrated. © 2014 Elsevier B.V. All rights reserved.


Zhang R.,University of Jinan | Zhang R.,Shandong Provincial Key Laboratory of Preparation and Measurement | Cheng X.,University of Jinan | Cheng X.,Shandong Provincial Key Laboratory of Preparation and Measurement | And 4 more authors.
Construction and Building Materials | Year: 2015

To better understand the influences of nano-TiO2 on the properties of cement-based materials, the hydration process, the compressive strength development, and the drying shrinkage of cement-based materials with the addition of nano-TiO2 of 25 nm were investigated. Results showed that nano-TiO2 increased the compressive strength of cement mortar through its acceleration on cement hydration and the pore-refining effect: 5 wt.% nano-TiO2 accelerated cement hydration process for 2 h and reduced the most probable pore size by 19.4%, 48.5%, and 54.4%, respectively. In addition, the influences of the hydrophilicity of nano-TiO2 on the water loss and volume stability of hardened cement pastes were primarily investigated and discussed in this work. For a comparison study, nano-SiO2 of 30 nm size was also used. Results showed that the decline of the contact angle and the refining of pore structure with the addition of nano-TiO2 slowed down the water loss of hardened cement paste, which resulted in a comparable drying shrinkage to that of the control sample at 1 month age. © 2015 Elsevier Ltd.

Discover hidden collaborations