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排序方式: 共有160条查询结果,搜索用时 15 毫秒
1.
In this investigation, low-cement castables were prepared using 70% alumina grog aggregates obtained from crushed alumina brick waste. The aggregates were thermally treated at 1550 °C for 3 h. Four types of low-cement castables were prepared with various types of aggregates (alumina grog with or without thermal treatment) and fillers (with or without zircon addition), and they were evaluated in terms of their physical, thermal, and chemical properties. Microstructural analysis via scanning electron microscopy (SEM) was performed on the castables before and after slag attack. Compared to the other fabricated castables, the thermally treated alumina grog castables with zircon showed better physical properties, such as a higher bulk density, cold crushing strength, and modulus of rupture and a lower apparent porosity and water absorption. In addition, they had a higher positive linear thermal expansion, refractoriness under load, permanent linear change, and hot modulus of rupture. The results of the SEM with energy dispersive X-ray analysis of the prepared castables confirmed that the mullite and anorthite phases were predominant when zircon was not added and the zircon–mullite phase additionally appeared upon the incorporation of zircon. A quantitative elemental analysis via X-ray fluorescence spectroscopy was employed to determine the composition of the castables. X-ray diffraction analysis showed that the alumina grog castables had a high mullite and low anorthite content, and the thermally treated alumina grog had a high anorthite, low mullite, and high zircon content. The improvement in the mechanical and thermo-mechanical properties of the castables with thermally treated alumina grog and added zircon can be attributed to the formation of the zircon–mullite phase with a low mullite phase content. 相似文献
2.
利用等离子分解锆英石(PDZ)和锆英粉与Al2O3反应烧结制备了ZiO2-SiO2-Al2O3系复相陶瓷。利用XRD、SEM、反光显微镜、显微硬度计等测试手段,对烧成试样的物相组成、显微结构、显微硬度、气孔状况及耐磨性进行了测试分析与讨论。研究结果表明:含镁助剂的加入促进了反应烧结;由PDZ制备的试样的性能优于锆英粉原料的试样:较佳的原料配比为No.4即Al2O3:PDZ=3:1,其耐磨性优于氧化铝质研磨体,适宜的烧成温度范围是1580℃-1600℃。 相似文献
3.
添加物对氮化硼材料性能的影响 总被引:1,自引:1,他引:1
研究了引入锆英石和氧化铝等添加物的热压氮化硼材料的抗氧化性、热震稳定性及力学性能。结果表明,向氮化硼中引入锆英石和氧化铝后,虽然未能按预期设想生成莫来石,但却对提高氮化硼材料的抗氧化性、热震稳定性及力学性能有利。 相似文献
4.
5.
《Ceramics International》2022,48(20):29997-30004
Stabling crystal structure at room temperature is a classic problem in the study of Zirconium dioxide (ZrO2). However, there are few investigations on making tetragonal zirconia (t-ZrO2) in one step at a low cost. In this research, t-ZrO2 is synthesized using a one-step high-temperature solid-state sintering technique with magnesite, dolomite, and limestone as stabilizers and zircon as the raw material. The most suitable stabilizers and reaction conditions are determined, and the mechanism of zirconia structure stabilization is explored. The findings suggest that magnesite has the lowest effect as a crystal structure stabilizer, whereas dolomite and limestone are pretty close, but dolomite introduces more impurities. The ideal reaction conditions were 60% mol limestone at 1500 °C. The stabilization mechanism is zirconia gap correction, according to XRD and EPR data. The characterization of the SEM demonstrates that the heat treatment temperature and stabilizer had little effect on the morphology of t-ZrO2. When limestone was introduced throughout the process, EDS data revealed that some amorphous silicon-calcium compounds occurred in the product. The focus of follow-up work will be on how to lessen the impact in this area. This research offers vital reference value for reducing the cost of the synthetic t-ZrO2 process. 相似文献
6.
文章通过中天山东段国宝山天河石花岗岩岩石地球化学和锆石U-Pb定年研究,探讨其成岩年龄、岩体成因和成岩构造背景。该花岗岩具富硅(Si O_2=72. 70%~74. 20%)、富碱(Na_2O+K_2O=8. 99%~9. 20%)、钠质(Na_2O/K_2O=1. 35~1. 55)、弱过铝(A/CNK=1. 01~1. 08)和铁质(Fe O~T/MgO=4. 11~57. 77)特征,岩浆分异指数较高(DI=94. 01~95. 83);富集U、Sm、Zr、Hf、Ta等高场强元素(HFSE)和Rb、Nd、Pb元素,亏损Sr、P、Eu、Ti、Y等元素,稀土总量低(∑REE=55. 34×10~(-6)~140. 52×10~(-6)),轻稀土较重稀土略富集(LREE/HREE=0. 97~1. 47),具明显的铕负异常(δEu=0. 003~0. 04)。锆石U-Pb定年结果显示国宝山天河石花岗岩年龄为(247±3) Ma,天河石伟晶岩脉侵位于(202±3) Ma。天河石花岗岩岩石地球化学特征表明其为典型的A型花岗岩,结合区域地质背景分析,显示该岩体形成于板内张性构造环境;天湖岩群和星星峡岩群中的片岩和片麻岩为国宝山天河石花岗岩的主要贡献源岩,幔源岩浆内侵于中地壳使之发生部分熔融,且母岩浆经历了较强的结晶作用。 相似文献
7.
《Ceramics International》2020,46(17):26572-26580
Zircon (ZrO2·SiO2) powder filler and colloidal silica binder were used to prepare the ceramic shell moulds for investment casting of shrouded low-pressure turbine blades (LPTB). Ceramic slurries were prepared by using two types of colloidal silica binders (polymer-free binder A and polymer-containing binder B). The samples prepared from binder B showed lesser self-load sag values than those developed from binder A. Ceramic shell moulds made from an optimized slurry composition (having binder A) yielded aeronautical grade casting of blades at 1500 °C with required dimensional accuracy and average surface roughness (Ra). The blades cast from shell moulds (having binder B) showed dimensional accuracy at 1500 °C as well as at 1525 °C. The Ra values of blades cast at 1500 °C and 1525 °C by using shell system with binder B were observed to be higher than those cast from shell system having binder A. 相似文献
8.
研究了锆英石微粉对镁质浇注料结构及性能的影响。结果表明:微粉粒径一定时,控制锆英石微粉加入量可以明显改善镁质浇注料显微结构和性能。由于MgO同ZrSiO4反应形成的ZrO2,能吸收渣中的CaO形成CaZrO3,堵塞材料中的气孔,同时提高熔海粘度,抑制了渣的渗透。 相似文献
9.
通过引入合成硼酸锌及活化处理锆英石粉制备了烧成温度低、乳浊度高的生料乳浊釉,并讨论了硼酸锌及锆英石粉活化处理对乳浊釉性能的影响。 相似文献