真空雾化制备CoCrAlTaY高温合金粉末及其涂层抗氧化性能
发布时间：2018-12-17 00:53
【摘要】：钴基高温合金涂层具有良好的抗氧化性能,在服役过程中表现出较好的涂层粘结性能,对涂层的寿命延长具有积极的作用。目前,CoCrAlTaY高温合金粉末中存在严重的Ta偏聚问题。从而导致涂层中也存在Ta偏聚,降低了涂层的抗高温氧化性能,严重影响了涂层的使用寿命。本文主要对真空雾化设备所涉及的相关工艺参数进行了优化,采用真空雾化法自制CoCrAlTaY高温合金粉末,并以其为粘结层制备热障涂层,最后对CoCrAlTaY高温合金粉末相关特性和涂层的抗高温氧化性能进行了初步分析研究。具体研究内容与结果如下：为了制备高质量的粉末,对实验所采用的熔炼温度、雾化温度、雾化压力、导流管直径等相关工艺参数进行了优化。同时,为了避免粉末中出现Ta的偏聚,实验采用CoTa中间合金作为Ta的原料制备CoCrAlTaY高温合金粉末,并对粉末相关特性进行研究,结果表明：采用CoTa合金代替Ta为原料制备的粉末,其微观组织较为均匀,白色块状物质几乎消失,但微区内仍存在絮状Ta；粉末中主要存在γ'、Cr23C6和TaC相,其中Ta主要以TaC和CoTa3的形式存在,其余弥散分布于整个粉末颗粒中。以自制粉末为粘结层制备热障涂层,初步研究温度与氧化方式、水蒸气环境以及粘结层成分等因素对热障涂层试样的抗高温氧化性能和寿命的影响。结果表明：相比于1050℃,试样于1000℃下的热障涂层寿命更长,这可能是由于增加的50℃促进了热氧化物(TGO)的生长和元素间的互扩散所致；由于在循环氧化条件下产生会应力,因此相比持续氧化,经循环氧化后热障涂层试样的寿命缩短了近二分之一；在高氧分压水蒸气环境中,裂缝的生长和扩散更为快速、简单,热障涂层的使用寿命更短；由于Co基粘结层具有较低的热膨胀系数,因此相比1050℃的温度循环条件下,自制CoCrAlTaY高温合金粉末为粘结层的热障涂层试样,经1100℃循环氧化后,其使用寿命比含有富Ni相的NiCoCrAlTaY粘结层更长。
[Abstract]:Co-based superalloy coating has good oxidation resistance and good adhesion during service, which has a positive effect on prolonging the life of the coating. At present, there is a serious problem of Ta segregation in CoCrAlTaY superalloy powder. As a result, Ta segregation also exists in the coating, which reduces the oxidation resistance of the coating at high temperature and seriously affects the service life of the coating. In this paper, the related technological parameters of vacuum atomization equipment were optimized. CoCrAlTaY superalloy powder was prepared by vacuum atomization method and used as adhesive layer to prepare thermal barrier coating. Finally, the properties of CoCrAlTaY superalloy powder and the oxidation resistance of the coating were studied. The main contents and results are as follows: in order to prepare high quality powder, the process parameters such as melting temperature, atomization pressure, pipe diameter and so on were optimized. At the same time, in order to avoid the segregation of Ta in the powder, the CoTa master alloy was used as the raw material of Ta to prepare the CoCrAlTaY superalloy powder, and the related properties of the powder were studied. The results showed that the powder prepared by using CoTa alloy instead of Ta as raw material, The microstructure was uniform, the white mass almost disappeared, but the flocculent Ta; still existed in the microzone. There are mainly 纬', Cr23C6 and TaC phases in the powder, in which Ta exists mainly in the form of TaC and CoTa3, and the other dispersions are distributed in the whole powder particles. Thermal barrier coatings were prepared by using self-made powder as bonding layer. The effects of temperature, oxidation mode, water vapor environment and composition of bonding layer on the oxidation resistance and life of thermal barrier coatings were studied. The results show that the lifetime of thermal barrier coating at 1000 鈩，
本文编号：2383348
[Abstract]:Co-based superalloy coating has good oxidation resistance and good adhesion during service, which has a positive effect on prolonging the life of the coating. At present, there is a serious problem of Ta segregation in CoCrAlTaY superalloy powder. As a result, Ta segregation also exists in the coating, which reduces the oxidation resistance of the coating at high temperature and seriously affects the service life of the coating. In this paper, the related technological parameters of vacuum atomization equipment were optimized. CoCrAlTaY superalloy powder was prepared by vacuum atomization method and used as adhesive layer to prepare thermal barrier coating. Finally, the properties of CoCrAlTaY superalloy powder and the oxidation resistance of the coating were studied. The main contents and results are as follows: in order to prepare high quality powder, the process parameters such as melting temperature, atomization pressure, pipe diameter and so on were optimized. At the same time, in order to avoid the segregation of Ta in the powder, the CoTa master alloy was used as the raw material of Ta to prepare the CoCrAlTaY superalloy powder, and the related properties of the powder were studied. The results showed that the powder prepared by using CoTa alloy instead of Ta as raw material, The microstructure was uniform, the white mass almost disappeared, but the flocculent Ta; still existed in the microzone. There are mainly 纬', Cr23C6 and TaC phases in the powder, in which Ta exists mainly in the form of TaC and CoTa3, and the other dispersions are distributed in the whole powder particles. Thermal barrier coatings were prepared by using self-made powder as bonding layer. The effects of temperature, oxidation mode, water vapor environment and composition of bonding layer on the oxidation resistance and life of thermal barrier coatings were studied. The results show that the lifetime of thermal barrier coating at 1000 鈩，
本文编号：2383348
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