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高炉风口上超音速火焰喷涂金属-陶瓷梯度层的可行性 总被引:2,自引:0,他引:2
在高炉风口表面制备一层适宜的金属-陶瓷梯度热障涂层,是提高风口寿命的一种有效的方法.本文旨在验证在风口上制备金属-陶瓷梯度保护层,提高高炉风口寿命的可行性.通过大型的有限元仿真软件AN-SYS,模拟分析了在紫铜表面喷涂陶瓷热障层的隔热效果,并且探讨了HVOF涂层的性能.结果发现,仅仅0.4 mm厚的ZrO2涂层就可以使铜基体温降200℃左右,而且超音速火焰喷涂打底的金属-陶瓷涂层的抗氧化性、热震性优于其他喷涂方法,这表示能够从材料和工艺两方面解决风口喷涂陶瓷层易脱落的问题.证明了在风口上喷涂金属-陶瓷梯度热障涂层的可行性以及利用HVOF打底层制备金属-陶瓷热障层的优势. 相似文献
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为了评价陶瓷/金属梯度热障涂层的性能,设计了4种涂层方案和2种基体材料(1Cr18Ni9Ti和2Cr13).利用单枪单送粉器成功地制备了线性梯度涂层.通过观察涂层的微观结构、测量涂层的抗热震性能和热残余应力来评价涂层的性能.利用扫描电镜对各种陶瓷涂层的微观结构进行了观察和分析,利用X射线能谱分析得到了陶瓷梯度涂层试样中的不同区域的衍射图.热震试验表明,梯度涂层比非梯度涂层具有更好的抗热震性能.采用钻孔法对不同涂层方案进行了残余应力的测量,结果表明,压应力出现在1Cr18Ni9Ti基体材料上,而拉应力出现在2Cr13基体材料上. 相似文献
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一、引言 金属—陶瓷梯度功能材料(FGM)是具有全新材料复合概念的新型复合材料。它以金属和陶瓷为基本原材料,通过控制材料的组成和微观结构的梯度分布,消除传统的金属和陶瓷复合材料的性能不匹配界面,充分发挥金属和陶瓷的优异性能。金属—陶瓷梯度功能材料实质上是为了解决金属和陶瓷的界面连接问题。金属—陶瓷梯度功能材料是一种高新复合材料,具有优异的性能和可设计性,引起了材料科学工作者们的高度重视。金属—陶瓷由于能够缓和热应力,是未来航天飞行的理想耐热、隔热材料,同时在核能、电子、化学和生物医学等领域有着广阔的应用前景。 二、金属—陶瓷FGM的开发研究背景 梯度功能材料是日本学者于1984年首先提出来的。这一新材料的设想,与高新的航天技术的发展密切相关。航天飞机是人类征服宇宙空间时必需的运载工具。众所周知,目前的航天飞机是由火箭助推,垂直地 相似文献
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涡轮叶片的热障涂层技术是保障和提升航空发动机性能的关键技术之一,涡轮叶片的工作环境要求热障涂层需要具备隔热性能好、热膨胀系数与基材相匹配、抗氧化性能好、抗熔盐腐蚀性能好等一系列特点,这对热障涂层的材料、结构以及制备工艺提出了巨大的挑战,是当前航空发动机领域的热点研究之一。本文对构成热障涂层的金属粘结层和陶瓷层材料,以及热障涂层体系结构的研究现状做了详细介绍,并简要介绍了常用的热障涂层制备方法,展望了金属粘结层和陶瓷层材料体系和制备技术的发展趋势,以期为未来航空发动机涡轮叶片热障涂层体系的构建提供有益参考。 相似文献
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研究机械力作用下金属,陶瓷功能梯度薄板1/3次亚谐共振问题。按照功能梯度薄板的非线性动力学方程,得到金属,陶瓷功能梯度薄板受横向机械力作用的非线性振动方程。应用非线性振动的多尺度法得到系统1/3次亚谐共振近似解并进行数值计算。分析阻尼、激励、几何尺寸等参数对系统1/3次亚谐共振幅频响应曲线的影响。 相似文献
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研究机械力作用下金属/陶瓷功能梯度薄板3次超谐共振问题.按照功能梯度薄板的非线性动力学方程,得到金属/陶瓷功能梯度薄板受横向机械力作用的非线性振动方程。应用非线性振动的多尺度法得到系统3次超谐共振近似解并进行数值计算。分析阻尼、激励、几何尺寸等参数对系统3次超谐共振幅频响应曲线的影响. 相似文献
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等离子喷涂热障涂层隔热性能分析方法 总被引:3,自引:1,他引:2
热障涂层材料已成为现代高性能航空发动机的关键材料,而隔热性能一直是评价热障涂层性能的一个重要指标。首先基于傅里叶导热定律,推导出一维稳态温度场的解析表达式,并讨论了陶瓷层厚度、陶瓷层上表面工作温度和金属基底下表面工作温度对热障涂层系统隔热性能的影响。设计了一种比较新颖的实验测试方法,成功实现了对热障涂层系统内部不同位置的温度进行实时测试和保存实验数据。结果表明,各个温度采集点的实验测试结果与理论预测结果吻合很好,说明提出的实验测试方法可以有效评估不同类型的热障涂层材料体系的隔热性能。 相似文献
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Internal cooling passages and thermal barrier coatings (TBCs) are presently used to control metal temperatures in gas turbine
blades. Functionally graded materials (FGMs), which are typically mixtures of ceramic and metal, have been proposed for use
in turbine blades because they possess smooth property gradients thereby rendering them more durable under thermal loads.
In the present work, a functionally graded model of an air-cooled turbine blade with airfoil geometry conforming to the NACA0012
is developed which is then used in a finite element algorithm to obtain a non-linear steady state solution to the heat equation
for the blade under convection and radiation boundary conditions. The effects of external gas temperature, coolant temperature,
surface emissivity changes and different average ceramic/metal content of the blade on the temperature distributions are examined.
Simulations are also carried out to compare cooling effectiveness of functionally graded blades with that of blades having
TBC. The results highlight the effect of including radiation in the simulation and also indicate that external gas temperature
influences the blade heat transfer more strongly. It is also seen that graded blades with about 70% ceramic content can deliver
better cooling effectiveness than conventional blades with TBC. 相似文献
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Thermal barrier coatings generally consist of a metallic substrate which is the primary structural component, a metallic bond coat which serves as oxygen diffusion barrier, a very thin layer of thermally grown oxide and a ceramic top coat that provides the main thermal shielding. Homogeneous ceramic coatings as top coats appear to have certain undesirable features such as high residual and thermal stresses, generally low toughness and relatively poor bonding strength. The new concept of compositional grading of the top coat may help to overcome some of these shortcomings by eliminating the material property discontinuities. A common mode of failure in thermal barrier coatings seems to be the debonding of the top coat. In this study the related interface crack problem for a graded ceramic/metal top coat is considered. It is assumed that the thermophysical properties of the top coat continuously vary between that of the bond coat at the top coat-bond coat interface and that of the ceramic at and near the free surface. The main objective of the study is to examine the influence of the material nonhomogeneity parameters and relative dimensions on the stress intensity factors and the crack opening displacements. 相似文献
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寻求具有良好热物理性能的新型陶瓷材料是热障涂层领域的研究热点之一。本研究采用固相反应法制备了(Sm0.2Gd0.2Dy0.2Y0.2Yb0.2)3TaO7高熵陶瓷材料, 对其晶体结构、显微组织、元素分布、结构稳定性和热物理性能进行了研究。结果表明: 制备的高熵陶瓷具有单一的缺陷萤石结构, 元素分布均匀, 晶粒尺寸在0.2~3 μm之间。经高温循环热处理后依然保持单一的萤石结构, 表现出良好的高温结构稳定性。25~800 ℃范围内热导率为0.72~0.74 W/(m?K), 远低于7YSZ, 1200 ℃下的热膨胀系数约为5.6×10-6K-1, 低于热障涂层(TBCs)对表面陶瓷层材料的要求, 但与环境障涂层(EBCs)硅基陶瓷基体的热膨胀系数((3.4~5.5)×10-6K-1)接近。 相似文献
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Microstructural changes to metal bond coatings on gas turbine alloys with time at high temperature 总被引:1,自引:0,他引:1
Complex coating systems are required to protect nickel-based super alloys from high temperature oxidation and corrosion. Industrial gas turbine blades and heat shields are generally plasma sprayed with a metal bond coating containing nickel, chromium, cobalt, aluminium and yttrium, and then an external thermal barrier coating of yttria-stabilised zirconia is applied. In this study, samples of an IN939 alloy heat shield with both a metal bond coat and a ceramic thermal barrier coating have been heated in air at high temperature for up to 2000 hours to assess the long term stability of the metal bond coat. Polished sections of the heat treated samples were examined by SEM and EDX to determine microstructural changes. The Ni-Cr-Co-Al-Y coating was found to be a very effective barrier against oxidation; the only apparent oxidation being the growth of an alumina layer between the bond coat and ceramic thermal barrier coating. With time, the growth of the Ni3Al phase in the metallic bond coat was observed, with extensive diffusion of other elements to and from the bond coat. 相似文献
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