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摘要传统热控百叶窗体积大、质量重，静电式开关的热控制所需的驱动电压过高，电致变色热控器件在使用过程中存在衰退现象且需要电力驱动，这些缺点使得它们都难以满足微小型航天器重量严格受控的要求。掺杂钙钛矿型锰氧化物有着诸多独特的物理性质，其中金属-绝缘相转变使其在高温时表现为高发射率的绝缘特性，低温时可表现为低发射率的金属性。用这种热致变色材料做成的热辐射表面无需动力装置就可根据外部环境以及内部热载的变化自动的调节自身的发射率，从而实现卫星的智能热控制。本论文从微小型航天器热控轻量化角度出发，研究了基于 Ba 掺杂钙钛矿型锰氧化物热致变色薄膜的辐射特性，并与 Sr 掺杂薄膜进行了比较，结果表明：Ba 掺杂 La0.7Ba0.3MnO3薄膜（在 YSZ 和 Si 基底上）发射率变化较小。YSZ 基底上的 La0.7Sr0.3MnO3 薄膜发射率的变化幅度最大，在温度为97K到373K的范围内，发射率变化了0.387，其金属绝缘相转变温度也降低至313K左右。 19288
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毕业论文关键词 可变发射率，Ba掺杂锰氧化物，光谱反射率，热致变色薄膜
Title Preparation for Ba doped thermalchromic thin film and
investigation on its thermal radiation Properties
Abstract
Due to the development of micro-spacecraft, there is an increasing demand for
micro-spacecraft to reduce the weight of thermal control devices. Traditional thermal
control devices all have some drawbacks. For example, Traditional shutter is too
bulky and heavy and MEMS shutter is inconvenient for preparation. The voltage
needed to drive the electrostatic thermal switch is too high. There is also a
problem for electrochromic thermal control devices which they would undergo the
degradation of electrochromic. These problems make them inappropriate be applied in
micro-spacecraft which have an extremely strict standard on its weight control. These
doped perovskite-type manganese oxides have many unique physical properties. For
example, the material shows an increased emissivity upon heating based on the
properties of metal-insulator transition. Namely, they show a metallic behavior with
low emissivity at low temperature, on the contrary, at high temperature they show high
emissivity which suggests insulating nature. The radiation surface fabricated by these
materials can automatically adjust its infrared emissivity to high or low in response to
variation of thermal load and environment temperature without any electrical and
mechanical parts, which makes micro-spacecraft realize the smart thermal control.
From the perspective of light-weight demand for the thermal control of
micro-spacecraft, this thesis investigates the thermal radiation property of the
thermalchromic thin films based on Ba doped perovskite-type manganese oxides and
compares it with Sr doped perovskite-type manganese oxides thin film spurted on the
YSZ substrate. The following main results were obtained: Firstly, the present studies of
thermalchromic material are briefly introduced. Secondly, the preparations of target
material are mainly introduced and the methods which the predecessors used to prepare
bulk ceramic materials are summarized. The fabrication process of solid state reaction
method for the target material is also introduced. Thirdly, some widely used methods in
producing thin films are presented and a detailed introduction of the method we used in
this experiment is given. Lastly, Fourier transform infrared spectrometer is used to
measure the spectral reflectivity under different temperature. And then thermal
emissivity is obtained by integrating the temperature-dependent reflectivity.