【摘要】：近年來隨著鐵電單晶在超聲醫(yī)學(xué)、傳感器、水聲換能器的廣泛應(yīng)用,生長尺寸大,性能穩(wěn)定的鐵電單晶成為研究的重點領(lǐng)域。目前生長鐵電單晶的方法主要有高溫溶液法,降溫法和布里奇曼法,其中又以布里奇曼法生長出的鐵電單晶尺寸較大,性能較穩(wěn)定。但是,在鐵電單晶生長過程中存在著組分偏析、熔體對流等因素以至于生長出的鐵電單晶無法達到預(yù)期。因此,開展鐵電單晶生長設(shè)備溫度場的模擬和分析以及磁場對鐵電單晶生長作用的影響,對生長更大尺寸,更好性能的鐵電材料研究具有重大的意義。本文的工作分為三部分：第一是對鐵電單晶生長爐爐體結(jié)構(gòu)的設(shè)計,第二是基于設(shè)計的爐體結(jié)構(gòu)對爐體溫度場的模擬,其中溫度場模擬又分為橫向溫度場的模擬和縱向溫度場的模擬。第三是設(shè)計合理磁場結(jié)構(gòu)以達到在爐體內(nèi)部引入一定強度的磁場的目的,并對引入磁場的強度進行有限元模擬和分析。上述工作得出如下結(jié)果：設(shè)計了三段式的鐵電單晶爐。爐體高度為1082mm,爐體直徑402mm,保溫層厚度為280mm。高溫段高度為300mm,加熱組件是硅鉬棒。中溫段高度為200mm,加熱組件是電阻絲。低溫段為300mm,加熱組件是電阻絲。用ANSYS有限元模擬軟件對鐵電單晶生長爐的橫向溫度場進行了模擬,得出溫度在徑向的分布曲線,發(fā)現(xiàn)該曲線是非線性的；有限元模擬得出在爐體外殼處的溫度為108.65℃,此溫度是后續(xù)磁場結(jié)構(gòu)設(shè)計及磁鐵材料選擇的主要考慮因素。用ANSYS有限元模擬軟件,在降溫法生長鐵電單晶的條件下對單晶生長爐縱向溫度場進行了模擬,得出軸向溫度分布曲線,通過對模擬數(shù)據(jù)的提取,得出爐體以一定速率降溫時1032℃等溫面和1265℃等溫面的位置-時間關(guān)系曲線都是非線性的。針對本文設(shè)計的爐體結(jié)構(gòu)設(shè)計了兩種磁場結(jié)構(gòu),利用Femm有限元分析軟件對兩種磁場結(jié)構(gòu)進行了模擬。一種結(jié)構(gòu)是無鐵厄的磁環(huán),模擬結(jié)果顯示在中心處可以產(chǎn)生約420mT的均勻磁場。另一種結(jié)構(gòu)是有鐵厄的磁環(huán),模擬結(jié)果顯示在中心處可產(chǎn)生160mT的均勻磁場。
[Abstract]:In recent years, with the wide application of ferroelectric single crystals in ultrasonic medicine, sensors and underwater acoustic transducers, ferroelectric single crystals with large growth size and stable performance have become the focus of research. At present, the main methods of growth of ferroelectric single crystals are high temperature solution method, cooling method and Bridgman method. Among them, the size of ferroelectric single crystals grown by Bridgman method is large and the properties are stable. However, in the growth process of ferroelectric single crystals, there are some factors, such as component segregation, melt convection and so on, so that the growth of ferroelectric single crystals can not meet the expectations. Therefore, the simulation and analysis of the temperature field of ferroelectric single crystal growth equipment and the effect of magnetic field on the growth of ferroelectric single crystal are of great significance to the study of ferroelectric materials with larger size and better performance. The work of this paper is divided into three parts: the first is the design of the furnace structure of ferroelectric single crystal growth furnace, and the second is the simulation of the furnace body temperature field based on the designed furnace structure. The simulation of temperature field is divided into the simulation of transverse temperature field and the simulation of longitudinal temperature field. The third is to design a reasonable magnetic field structure to achieve the purpose of introducing a certain intensity of magnetic field in the furnace body and to simulate and analyze the intensity of the magnetic field by finite element method. The results are as follows: a three-stage ferroelectric single crystal furnace is designed. The height of furnace is 1082 mm, the diameter of furnace is 402 mm and the thickness of insulation layer is 280 mm. The high temperature section height is 300 mm, the heating module is silicon molybdenum rod. The height of the middle temperature section is 200 mm, and the heating module is a resistance wire. The low temperature section is 300 mm and the heating module is resistance wire. The transverse temperature field of ferroelectric monocrystalline growth furnace was simulated by ANSYS finite element simulation software. The temperature distribution curve in radial direction was found to be nonlinear, and the temperature at the furnace shell was 108.65 鈩，

本文編號：2244189