【作者】 刘鹏；

【导师】 王昕；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2021， 硕士

【摘要】 飞行器发动机尾喷口的后向散射是阻碍其实现全向低可探测技术的关键,但其位置的温度较高,常见的电吸收材料和磁吸收材料的应用均受到了较大限制,由此应用大气等离子喷涂(Atmospheric plasma spraying,APS)技术提出并设计了铁磁陶瓷复合吸波涂层,希望解决高温低可探测的技术难题,达到降低雷达散射截面的效果。针对APS工艺制备涂层时喷涂粉末的粒径分布、微观形貌等的特别要求,本文利用喷雾造粒技术制备了复合颗粒,采用响应曲面法对相关工艺参数进行了系统的研究,并通过数学方法拟合参数获得了模型公式,使用最终得到的参数造粒并制备了涂层,进行了相关的测试,基本实现了粉体制备的课题指标,所得到主要结论如下:1.在喷雾造粒的前驱体浆料的制备过程中很多因素对粉末粒径、流动性和球形度均有较大影响,经过响应曲面实验探究,最佳的工艺参数比例为:固含量50%,无机增稠剂含量为4.372%,球磨比为500%,根据公式预测拟合可以得到:D10为41.219μm,D50为58.066μm,D90为80.582μm,流出时间为119.155 s/50g,偏心率为1.055;2.喷雾造粒过程中的工艺参数同样对粉末的粒径、流动性和球形度有重要影响,经过响应曲面实验探究,最佳的工艺参数比例为:进风温度276.0℃,进风温度100.0℃,喷头频率26.1 Hz,粘结剂含量2.49%,分散剂含量0.09%,此时拟合可以得到:D10为18.79μm,D50为42.65μm,D90为75.28μm,其流出时间约为100.0 s/50g,偏心率为0.017;3.采用如上参数采用喷雾造粒工艺制得粉末并测试,其实验结果与理论拟合计算的误差大约为15%,模型具有一定的准确性和参考价值。随后使用造粒后粉末在APS工艺下制备得到了铁磁陶瓷复合高温吸波涂层,涂层整体的密度约为4960 kg/m~3,在厚度为200μm时结合强度为8 MPa。总之,本论文对喷雾造粒制备铁磁陶瓷复合粉末进行了较为深入的研究,得到了工艺参数的拟合公式,所制得的粉末可以满足APS的需求,而制备涂层工艺还有许多改进的空间,整体研究具有一定的工程意义和指导价值。更多还原

【Abstract】 The backscattering of aircraft engine tail nozzles can significantly hinder the realization of omnidirectional low detectability technology,while the preparation and application of conventional electro-absorption materials and magnetic absorption materials are greatly restricted due to the extreme high temperature at this location.In this application,Atmospheric plasma spraying(APS)technology is proposed and a ferromagnetic ceramic composite absorbing coating is designed,aiming to address the technical problem of high temperature and low detectability,and achieve the effect of reducing the radar cross section.Considering the special requirements of the particle size distribution and microscopic morphology of the sprayed powder when the coating is prepared by the APS process,in this paper,the spray granulation technology is employed to prepare composite particles,the response surface method is used to systematically study the relevant process parameters.The parameters are fitted through mathematics to obtain the model formula,the finally obtained parameters are applied to granulate and prepares the coating followed by related tests,the subject index of powder preparation is realized basically.The main conclusions obtained are as follows:1.During the spray granulated precursor slurry,many factors exhibit a great influence on the particle size,fluidity and sphericity of the powder.Through experimental exploration,the optimized process parameters are:the solid content is50%,the inorganic thickener content is 4.372%,and the content of the grinding ball is500%.According to the formula prediction and fitting,the D10 is 41.219μm,the D50is 58.066μm,the D90 is 80.582μm,the outflow time is 119.155 s/50g and the eccentricity is 1.055;2.The process parameters during the spray granulation also have an important impact on the particle size,fluidity and sphericity of the powder.The optimized process parameters are:the inlet air temperature 276.0℃,the wind air temperature 100.0℃,the nozzle frequency 26.1Hz,the binder content is 2.49%,the dispersant content is 0.09%.The fitting results are:the D10 is 18.79μm,the D50 is 42.65μm,the D90 is 75.28μm,the outflow time is 100.0 s/50g and the eccentricity is 0.017;3.The above parameters are used to granulate the powder for examination,the error between the experimental results and the theoretical fitting calculation is about15%,the model possesses certain accuracy and reference value.Then the granulated composite powder was used to prepare a ferromagnetic ceramic high-temperature absorbing coating through APS process.The density of the coating is about 4960 kg/m~3,and the bonding strength is about 8MPa under the thickness of 200μm.In summary,spray granulation technology is used in this paper to prepare ferromagnetic ceramic composite powders for further in-depth investigation and exploration,a more ideal process parameter fitting formula is achieved.The prepared powder can basically meet the needs of the APS process.The research results exhibit certain engineering significance and reference results.更多还原