排序方式: 共有42条查询结果,搜索用时 0 毫秒
1.
本文研究了湖北省襄阳县的含硅白云石制造釉面砖的反应过程。研究表明该矿石除白云石外还含有部分滑石和石英及少量其他矿物。以它为主要原料制造釉面砖时的反应机理是:白云石中的CaCO3、MgCO3与由粘土、滑石脱水而来的非晶态SiO2、Al2O3、MgO以及石英类原料产生固相反应,生成钙长石(Ca,Na)(Si、Al)4O8)和普通辉石(Ca(Mg,Al)(Si,Al)2O6),即将碳酸盐转变为架状和链状 相似文献
2.
3.
In the paper, the effect of heat-treatment on thestrength and toughness of AlN-SiC whisker composites with Y_2O_3+SiO_2 additives have been studied. When the sample contining 10wt%Y_2O_3+SiO_2(Y_2O_3/SiO_2=1/0. 66) was treated at 1330℃ in air for 140hours,the flexural strength of composites was raised from 481 MPa to784 MPa the toughness was also enhanced slightly. The phase composi-tion microstructure and grain boundary phase structure have been char-acterized by combining XDR, SEM, TEM/EDXA and HREM tech-niques. reinforcenent and toughening mechanism of the composites re-sults from the crystallization of glass phase in the grain boundary atthe high temperature oxidizing atmosphere to form the crossing struc-ture of 2H°sialon fibrous phase and SiC whisker 相似文献
4.
Aluminium nitride ceramics containing 15-30 w/o of SiC whiskers can be sintered tofull density(by hot pressing at 1800℃)using2-3 w/o of Y_2O_3,additions.The whiskersincrease the toughness and strength of thecomposite,K_(10) increasing from 2.8 to about5.0 and flexural strength increasing by 30-50%.However,the whiskers must be welldispersed and if the dispersion is notsatisfactory,toughness may increase but thestrength decreases.The hot-pressingtemperature can be reduced by up to 100℃ ifY(NO_3)_3 .5H_20 is used as the sinteringadditive instead of Y_2O_3,but some oxidation ofthe AIN occurs during heating.Isopropan-2-01 is a better dispersing agent thancyclohexane,but again some oxidation of theAIN does occur.The best sample prepared during this work contained 20 w/o of SiC whiskers and 2 w/oY_2O_3 added as Y(NO_3)_3. 5H_2O and mixed inisopropanol.This exhibited a mean strength of453MPa(maximum 522MPa,measured bydisc flexure)and a fracture toughness of5.5MPam~(1/2). 相似文献
5.
6.
7.
8.
利用长江淤泥制砖的调查分析 总被引:1,自引:0,他引:1
通过对长江淤泥进行化学分析、矿物分析及物理性能测定,对长江淤泥的性能及分布进行全面的评价。由此可以肯定,通过合理地利用,长江淤泥用于制造砖瓦是可行的。 相似文献
9.
通过X射线光电子能谱 (XPS)分析研究了碳热还原氮化法制备的AlN微粉的表面结合状态。结果表明 :AlN微粉的表面有明显的氧化层存在 ;AlN微粉表面结合状态为Al—O和Al—N复合型结合 ;杂质元素W主要是由球磨介质中的WC引入的 ,并以WO2 - 4形式分布于AlN微粉表面。 相似文献
10.
以Y_2O_3为烧结助剂,采用热压烧结法制备了AlN陶瓷。采用X—ray、SEM、EPA测试了样品的结构,确定了样品的相组成与相分布。探讨了抗弯强度与温度、抗弯强度与1300℃空气中氧化时间的关系。结果表明,在低于1300℃时强度随温度升高缓慢下降,在1300~1500℃时急剧下降。在1300℃空气中样品产生氧化,强度随氧化时间的增加不断下降。本文讨论了AlN陶瓷在不同温度范围及长时间在1300℃空气中氧化后的断裂机理。 相似文献