排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
相变增韧和层状复合协同强韧化Al2O3陶瓷 总被引:3,自引:0,他引:3
本文采用相变增韧和层状复合协同强韧化Al2O3复合陶瓷,相变增韧制备出ZTA陶瓷,在此基础上,采用层状复合工艺,制备出ZTA/BN陶瓷。研究结果表明:相变增韧和层状复合协同强韧化Al2O3能基本保持陶瓷抗弯强度,冲击韧性提高了37倍。 相似文献
2.
A hot-pressing reactive sintering (HPRS) technique was explored to prepare SiC coating for protecting carbon/carbon (C/C) composites against oxidation. The microstructures of the coatings were analyzed by X-ray diffraction and scanning electron microscopy. The results show that, SiC coating obtained by HPRS has a dense and crack-free structure, and the coated C/C lost mass by only 1.84 wt.% after thermal cycles between 1773 K and room temperature for 15 times. The flexural strength of the HPRS-SiC coated C/C is up to 140 MPa, higher than those of the bare C/C and the C/C with a SiC coating by pressure-less reactive sintering. The fracture mode of the C/C composites changes from a pseudo-plastic behavior to a brittle one after being coated with a HPRS-SiC coating. 相似文献
3.
Deng Jianxin Zhang HuiWu Ze Liu Aihua 《International Journal of Refractory Metals and Hard Materials》2011,29(5):631-638
The friction and wear behavior of the polycrystalline diamond (PCD) were evaluated in ambient air at temperatures up to 700 °C using a ball-on-disk high temperature tribometer. The wear surface features of the PCD were examined by scanning electron microscopy. Energy dispersive X-ray analysis was used to investigate the chemical composition. XRD experiments were performed to study the crystal structure of the PCD specimens at different temperatures. Results showed that the friction coefficient of the PCD is different depending on the temperature, and decreases with the increase of temperature. The PCD exhibited the lowest friction coefficient of approximately 0.16 in the case of 700 °C sliding operation. The difference of the worn surface features of the PCD after sliding at different temperatures is related to the chemical transformation during sliding wear tests. The surface damage of the PCD appears to happen around 600 °C accompanied by extensive Co phase extrusion out of PCD. Numerous micro-cracks both at the grain boundaries and in the grains are observed with the increase of temperature to 700 °C. At this temperature, surface graphitization of diamond is to be expected, and the formation of graphite on the wear track is beneficial to the reduction of friction coefficient. 相似文献
4.
An active and reactive combined spot price model and the corresponding algorithm are introduced in this paper based on the theory of optimal power flow. Different from the traditional economic dispatch in the field of spot price, the objective function is to minimize generation costs based on pricing reactive power. Then considering the characteristics of wind turbines, processing methods of wind farms in optimal power flow is discussed. Finally, the feasibility of the model and the algorithm is verified through the simulation results of IEEE 30 system. 相似文献
5.
1