金属基耐磨指示涂层中荧光粉的猝灭机理研究

发布时间：2019-05-10 23:21

【摘要】：新型高铝青铜磷光耐磨自敏涂层(Cu-14A1-X/SrAl_2O_4:Eu~(2+),Dy~(3+))不仅具有高铝青铜合金粉末良好的耐磨耐蚀性能,而且利用磷光材料优异的发光性能高效快捷的监测摩擦磨损状况,显示出重要的科学研究价值和广阔的应用前景。通常采用真空热压烧结、热喷涂、冷喷涂技术、电化学沉积、爆炸喷涂等技术制备耐磨自敏涂层,但由于涂层中的发光颗粒SrAl_2O_4:Eu~(2+),Dy~(3+)受制备环境的影响,如高温高压,金属接触,合金反应,高速碰撞等,对其中的磷光指示粒子的发光性能产生猝灭。本文通过真空热压烧结,超音速等离子喷涂和冷喷涂技术制备耐磨自敏涂层,将探讨不同制备工艺对金属基耐磨指示涂层中荧光粉的猝灭影响因素,并提出合理的猝灭机理。通过真空热压烧结技术在不同温度下制备耐磨自敏涂层,光谱观察发现随温度升高涂层发光强度出现一定程度增强,铝酸锶在涂层中的相结构并未改变且结晶性能越来越好,所以在烧结涂层中热猝灭并不是它主要的影响因素。在热压烧结过程中金属接触对涂层影响最大,采用铜基、镍基、锰基、铁基、高铝青铜分别复合SrAl_2O_4:Eu~(2+),Dy~(3+)制备不同金属基复合涂层,结果表明铝酸锶在烧结过程中受高铝青铜金属粉末影响,使荧光粉电子跃迁几率减小,削弱发光,且锰粉对磷光粉猝灭作用最大,镍粉对磷光粉的猝灭作用最小。通过改变超音速等离子喷涂氢气流量制备不同温度热喷涂涂层,随温度的升高,涂层发光性能降低,出现热猝灭现象。XRD分析发现涂层物相主要为Al Fe、Al Fe_3、Cu_9Al_4和SrAl_2O_4,除此之外还有发光杂质相SrAl_4O_7和Sr Fe_2O_4;涂层铝酸锶出现熔融趋势,但涂层表面变的平整,孔洞减少。荧光粉在超音速等离子喷涂耐磨指示涂层中主要受热猝灭影响,涂层中部分铝酸锶颗粒经等离子高温焰流加热获得高热能达到猝灭临界点,以振动能释放能量,增加无辐射跃迁几率。通过冷喷涂技术制备不同磷光粉体积分数的耐磨自敏涂层,随荧光粉含量增加,涂层表面发光粒子沉积率逐渐降低,超音速等离子喷涂涂层呈现相反的规律。冷喷涂涂层中铝酸锶硬质颗粒起到很好的喷丸和夯实作用,使得涂层厚度随磷光粒子含量的增加逐渐增大,表面由层叠状逐渐变得不规整。当磷光粉体积分数为30%时,冷喷涂涂层和热喷涂涂层磷光粉体积分数为25%的涂层沉积率一致。荧光粉在冷喷涂耐磨指示涂层中的猝灭主要是机械作用,铝酸锶粒子在喷涂时速度较大,硬质颗粒在获得较大动能后发生碎裂,使颗粒变小缺陷增加,机械作用力导致的猝灭大于热喷涂涂层中热猝灭效应。
[Abstract]:The new high aluminum bronze phosphorescence wear resistant self-sensitive coating (Cu-14A1-X/SrAl_2O_4:Eu~ (2), Dy~ (3) not only has good wear resistance and corrosion resistance of high aluminum bronze alloy powder. Moreover, the excellent luminous properties of phosphorescence materials are used to monitor friction and wear efficiently and quickly, which shows important scientific research value and broad application prospect. Wear-resistant self-sensitive coatings are usually prepared by vacuum hot pressing sintering, thermal spraying, cold spraying, electrochemical deposition, explosive spraying and so on, but because of the luminous particles SrAl_2O_4:Eu~ (2) in the coatings, Dy~ (3) is affected by the preparation environment, such as high temperature and high pressure, metal contact, alloy reaction, high speed collision and so on, which quenches the luminous properties of phosphorescence indicating particles. In this paper, wear-resistant self-sensitive coatings were prepared by vacuum hot pressing sintering, supersonic plasma spraying and cold spraying. The factors affecting the quenching of fluorescent powder in metal-based wear-resistant indicator coatings were discussed, and the reasonable quenching mechanism was put forward. Wear-resistant self-sensitive coatings were prepared by vacuum hot pressing sintering at different temperatures. It was found that the luminous intensity of the coatings increased to a certain extent with the increase of temperature. The phase structure of strontium aluminate in the coatings did not change and the crystallization properties became better and better. Therefore, thermal quenching is not the main influencing factor in sintered coatings. In the process of hot pressing sintering, metal contact has the greatest influence on the coating. Different metal base composite coatings are prepared by using copper base, nickel base, manganese base, iron base and high aluminum bronze composite SrAl_2O_4:Eu~ (2) and Dy~ (3), respectively. The results show that strontium aluminate is affected by high aluminum bronze metal powder during sintering, which reduces the electron transition probability of phosphor powder and weakens the emission. Manganese powder has the greatest quenching effect on phosphor powder and nickel powder has the smallest quenching effect on phosphor powder. Different temperature thermal spraying coatings were prepared by changing supersonic plasma spraying hydrogen flow rate. With the increase of temperature, the luminous properties of the coatings decreased and the thermal quenching phenomenon appeared. XRD analysis showed that the coating phase was mainly Al Fe,Al Fe_3,. In addition to Cu_9Al_4 and SrAl_2O_4, there are luminous impurity phases SrAl_4O_7 and Sr Fe_2O_4;. The melting trend of strontium aluminate appeared, but the surface of the coating became smooth and the pores decreased. The wear resistance of fluorescent powder in supersonic plasma spraying indicates that it is mainly affected by thermal quenching. Some strontium alginate particles in the coating are heated by plasma high temperature flame flow to obtain high thermal energy to reach the quenching critical point, and the vibration energy is released. Increase the probability of non-radiative transition. Wear-resistant self-sensitive coatings with different volume fraction of phosphor powder were prepared by cold spraying technology. with the increase of phosphor content, the deposition rate of luminous particles on the surface of the coating decreased gradually, and the supersonic plasma spraying coating showed the opposite law. Strontium alginate hard particles in cold spraying coating play a good role in shot peening and compaction, so that the thickness of the coating increases with the increase of phosphorescence particle content, and the surface becomes irregular from laminated to irregular. When the volume fraction of phosphor powder is 30%, the deposition rate of cold sprayed coating and thermal sprayed coating with 25% phosphor powder volume fraction is the same. The quenching of fluorescent powder in cold spraying wear resistance indicates that the quenching of strontium aluminate particles is mainly mechanical. Strontium aluminate particles are sprayed at a higher speed, and the hard particles break up after obtaining greater kinetic energy, which increases the size of the particles. The quenching effect caused by mechanical force is greater than that in thermal spraying coating.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4;TQ422

【参考文献】