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of Aeronautics and Astronautics, Beijing 100083, China) Abstract:The halide-activated pack cementation method is utilized to codeposit aluminum and silicon on Mo substrate. Emphasis is placed... substrate through the halide-activated pack cementation method. The resultant Si-Al coating on Mo substrate exhibits excellent cyclic oxidation resistance. The excellent cyclic oxidation resistance......
of dissolution and cementation. Compaction played a more important role than cementation in destroying the primary porosity of the sandstones. The reservoirs have experienced complicated diagenetic.../calcite/dolomite cementation→feldspar dissolution/the first stage of quartz overgrowth → early hydrocarbon filling→quartz dissolution/anhydrite/Fe-carbonate cementation→Fe-carbonate dissolution/feldspar......
复合包渗法制备铌合金表面硅化物涂层 蔡志刚1,易丹青1,王小宁1,许谅亮1,肖来荣1 (1.中南大学,材料科学与工程学院,长沙,410083) 摘要:采用复合包渗法在C103铌合金基体上制备硅化物涂层,进行1500℃静态氧化实验,室温~1500℃热震实验,利用X射线衍射(XRD),扫描电镜(SEM),能谱分析(EDS)等检测手段对涂层氧化前后的组织结构进行观察,分析涂层形成机理,硅化时间对涂层组织结构的影响以及涂层氧化前后组织形貌的变化.研究表明,复合包渗法制备硅化物涂层主要是通过扩散反应形成的;涂层是以MoSi2相为主体层的多相复合结构;在高温氧化环境下,涂层表面生成熔融态非晶玻璃膜,......
铌基超高温合金表面包埋Si-Y共渗涂层的显微组织 郭喜平1,田晓东1 (1.西北工业大学凝固技术国家重点实验室,西安,710072) 摘要:通过在1050和1150 ℃包埋Si-Y共渗5-20 h的方法在铌基超高温合金上制备抗氧化涂层,对涂层结构,相组成和形成过程进行了分析.结果表明:涂层主体为(Nb,X)Si2(X=Ti,Cr,Hf),向内依次为(Nb,X)5Si3过渡层和富Al扩散区;不同共渗条件下制备的涂层具有相似的结构,涂层生长的动力学曲线符合抛物线规律.能谱的半定量分析表明,渗层中的Y含量随共渗温度的升高增加显著,而随共渗时间的延长增加缓慢. 关键词:铌基超高温合金; Si-......
are the main pore types. Carbonate cementation is the main diagenetic event. There are differences in reservoir characteristics in the oil layer, water layer and dry layer. Primary pores in the oil layer are developed, and the content of carbonate cementation is low, mainly dolomite cementation. The porosity of water layer and dry layer is not developed, and the content of carbonate cementation......
temperature mechanical properties of carbon/carbon composite substrates, SiC coatings reinforced by SiC whiskers were prepared by pack cementation method. The effect of SiC whiskers on the oxidation resistance......
coatings were produced on P110 steel by pack cementation. The orthogonal array design (OAD) was applied to set the experiments. An artificial neural network (ANN) approach is employed to predict......
cementation and alkaline dissolution are the general diagenetic features of the tight sandstone reservoir in lower Shihezi formation. Cementation can be subdivided into three periods of siliceous cementation and two periods of calcareous cementation, and cementation is the main cause of reservoir densification. Diagenetic evolution process of the reservoir can be divided into four stages, i.e., fast compact......
of Co Sb H 2O system shows that the thermodynamic driving power of removal of cobalt by cementation using zinc powder is raised when metallic compound (CoSb) is formed between cobalt and antimony during removal of cobalt by cementation using zinc powder; scanning electron microscopy and X ray diffraction display that antimony exsits in the same forms with nickel and cobalt. It is clear......
铌硅化物基超高温合金表面包埋渗Al改性硅化物涂层的组织结构 郭喜平1,田晓东1 (1.西北工业大学凝固技术国家重点实验室,西安,710072) 摘要:分别采用两步包埋渗法和包埋共渗法在铌硅化物基合金表面制备了Al改性硅化物抗氧化涂层.两步包埋渗法是先在合金表面包埋渗Si制备(Nb,X)Si2(X表示Ti,Cr和Hf元素)涂层,然后再将渗Si试样于800~1000℃包埋渗Al.结果表明:当渗Al温度达到860℃时渗入(Nb,X)Si2层中的Al可形成(Nb,Ti)3Si5Al2相;当渗Al温度达到900℃时渗入的Al还可穿过(Nb,X)Si2层在渗Si层与基体之间形成(Nb,Ti)(Al,......
