Thermal Shock Resistance Behavior of Alumina Ceramics Incorporated with Boron Nitride Nanotubes

2011 ◽  
Vol 94 (8) ◽  
pp. 2304-2307 ◽  
Author(s):  
Wei-Li Wang ◽  
Jian-Qiang Bi ◽  
Kang-Ning Sun ◽  
Ming Du ◽  
Na-Na Long ◽  
...  
2007 ◽  
Vol 544-545 ◽  
pp. 379-382
Author(s):  
Kyung Hun Jang ◽  
Bum Rae Cho

The effect of CaO, MgO and SiO2 as a flux on the sinterability of zirconia toughened alumina(ZTA) used for plasma reactors was investigated and the effect of zircon addition on thermal shock resistance of ZTA with 15wt.% of ZrO2 was also investigated. The resultant data revealed that ZTA shows the best sinterability at the composition of 2wt.% of CaO, 4wt.% of MgO and 2wt.% of SiO2 and at the sintering temperature of 1350°C. Thermal shock resistance of ZTA containing zircon was improved significantly. It is shown that ZTA containing 10wt.% of zircon shows better thermal shock resistance than others. This fact can be explained due to the low thermal expansion coefficient of zircon. It was concluded that zircon is an effective material to improve thermal shock resistance of alumina ceramics.


2012 ◽  
Vol 509 ◽  
pp. 240-244
Author(s):  
Li Ying Tang ◽  
Xi Cheng ◽  
Ping Lu ◽  
Fang Yue

Abstract: Cordierite–alumina ceramics were prepared with the raw materials of cordierite and α-alumina powder, and TiO2,CuO and MgO were added as composite additives. The effect of MgO/ CuO ratios on the microstructure, thermal conductivity and thermal shock resistance of cordierite–alumina ceramics were researched by X-ray diffraction, scanning electron microscopy and laser flash analyzer; the bulk density and the porosity of cordierite – alumina ceramics were measured. The results show that with increasing of MgO/CuO ratios, the bulk density and thermal conductivity increase firstly and then decrease, and have a minimum with 0.4wt% MgO and 0.667 MgO/CuO; and the porosity of ceramics decreases firstly and then increases and has a maximum with 0.4wt% MgO and 0.667 MgO/CuO;There are little changes in the size of the grain of the ceramics, and a small amount of magnesium aluminate spinel precipitate; the thermal shock resistance performance of the ceramics is developed with the increasing of MgO/CuO ratios.


2011 ◽  
Vol 492 ◽  
pp. 333-336
Author(s):  
Kai Li ◽  
Lu Cun Guo

The thermal shock behavior of alumina ceramics tested by two different approaches, water and air quenching, using an automatic experimental set was investigated. The changes of the flexural strength before and after the thermal shock was measured and used as an indicator of thermal shock resistance. The study reveals that air quenching test has limited impact on the changes of flexural strength, whereas the water quenching yields considerable decreases of the strength. The alumina ceramics was quenched in water at various temperature differences for five cycles. It is shown that the retained strength of the quenched specimens decreases abruptly at the temperature difference of 300°C, which indicates a great severity of thermal shock in this point. The thermal shock behavior of the specimens is evaluated by quenching in water as three different temperature differences, ΔT, setting at 300°C, 600°C and 800°C, respectively. The results show, for three different ΔT quenches, the strength reductions caused by the quenching exhibit similar trends: After a sharp drop, the residual strength remains almost unchanged at a certain level for each given quenching temperature difference, and the turning points all fall in the very first five to ten thermal cycles range. And the rank of the damage severity of alumina ceramics among the three different temperature differences is: ΔT800°C > ΔT600°C > ΔT300°C


1979 ◽  
Vol 36 (9) ◽  
pp. 518-520
Author(s):  
L. P. Ivanova ◽  
N. N. Savanina ◽  
Yu. I. Kelin ◽  
A. P. Malygina

Sign in / Sign up

Export Citation Format

Share Document