【摘 要】
:
In this investigation, aluminide coatings used to protect industrial components at high temperature and corrosive environments were modified with silicon additi
【机 构】
:
Materials engineering department
论文部分内容阅读
In this investigation, aluminide coatings used to protect industrial components at high temperature and corrosive environments were modified with silicon addition and the microstructural features and formation mechanism were evaluated. The coating on the nickel-based superalloy IN738LC was carried out by a two stage process including siliconizing at first and aluminizing thereafter. Pack cementation siliconizing performed at 950℃ for 2, 4 and 6 hours in several powder mixtures of Si, Al2O3 and NH4Cl, then aluminum was diffused into the surface of the specimens by an industrial aluminizing process. The modified coatings were characterized by means of standard metallography, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction methods. The results show that Si in the coatings mainly presents in the form of secondary phases including Cr3Si, Mo5Si3 and Ni16Ti6Si7, well distributed within the NiAl matrix. The advantages of this two stage modified coating is discussed.
其他文献
AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and
Background Eosinophils are highly related to allergic asthma inflammation. Interleukin (IL)-5 is the major chemokine of eosinophils, inhibition of the activity
AIM: To investigate whether serum levels of two soluble forms of extracellular cytokeratin 18 (M30-antigen and M65-antigen) may differentiate nonalcoholic steat
AIM: To assess the diagnostic accuracy of endoscopic ultrasound (EUS), fluid tumor markers and cytology in distinguishing benign from (pre)malignant pancreatic
Background Pigment epithelium-derived factor (PEDF) is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present s
研究了从啤酒酵母泥悬液中提取的β-1,3/1,6-葡聚糖制剂(含25%β-1,3/1,6-葡聚糖)对凡纳对虾生长及免疫力的影响.基础饲料中分别添加3个水平(0.1%,0.2%和0.4%)的β-葡聚糖制
以超临界状态的LNG作为冷源,以工业余热作为热源的闭式Brayton循环,可以有效的利用LNG的冷(?)并回收工业余热。本文以(?)效率为评价准则,兼顾LNG冷(?)和工业余热的利用,对该
Background Dense congenital cataracts often cause severe visual impairment. The results of long-term follow-up of dense bilateral congenital cataract in China h
根据现有光电测量设备对高速图像数据和测量数据实时记录的要求,实现了一种基于SCSI硬盘的高速图像数据记录系统的技术。阐述了它的组成结构和基本原理、高速实时无压缩记录和测量参数同步存储的特点,通过高速图像数据记录技术在光电经纬仪的应用,设计了一种数字化、小型化的高速运动目标的特性测量系统。系统样机完成的指标结果表明:高速图像数据记录系统能够较好地完成图像的记录和目标的特性测量任务。
针对大规模细粒度网络流量测量的现实困难,本文引入一种非平稳型流量队列模型NTT,直接对粗粒度的流量采样进行建模.NTT模型是大量活跃的流量队列的迭加,每个队列内部的流量变