原子层沉积技术包覆超细金属粉体及其性能研究

发布时间：2018-04-09 10:02

  本文选题：原子层沉积　切入点：羰基铁粉　出处：《江苏大学》2017年硕士论文

【摘要】：原子层沉积(Atomic Layer Deposition,ALD)技术是一种先进的镀膜工艺,广泛应用于半导体、微电子等领域,并取得了令人称赞的效果。但对于超细金属粉体领域,该技术的研究还鲜有报道。由于超细金属粉体较高的表面活性,使得铜粉和铁粉在高温、潮湿环境下易氧化,这将损害材料的多种优良性能,所以需要解决在使用过程中的氧化问题。本文旨在通过原子层沉积技术制备性能优异的包覆型金属粉体材料,提高铁粉、铜粉的抗氧化性以及改善羰基铁粉吸波性能,并探索原子层沉积技术对粉体改性的应用前景。主要内容如下:(1)本文首次利用原子层沉积技术对微纳米级羰基铁粉(Carbonyl Iron Powder,CIP)进行表面包覆改性,以三甲基铝和水为前驱体,在羰基铁粉表面生长了无定型氧化铝薄层,通过调节ALD反应工艺参数,考察了不同工艺条件对包覆材料的影响,最终确定了适宜的工艺条件。进一步制备了25/50/75个ALD循环的羰基铁粉,通过扫描电子显微镜以及透射电镜分析,该氧化铝薄层致密均匀、与颗粒表面接触良好,包覆后的材料形貌轮廓清晰可见,显示出了原子层沉积技术优良的保型性,使用综合热分析仪对包覆后的羰基铁粉进行分析,结果显示包覆后的材料具有优异的抗氧化性,且随着包覆圈数的增加而增强,盐酸腐蚀实验表明包覆后的材料具有良好的抗腐蚀性。利用矢量网络分析仪等技术手段系统分析了改性前后羰基铁粉的电磁性能指标,结果表明改性后介电常数减小显著,磁导率变化相对较小,改善了原羰基铁粉的电磁参数,提高了材料的阻抗匹配性。(2)首次采用原子层沉积技术,以三甲基铝和水为前驱体对微细铜粉进行表面包覆,研究了直接包覆、异丙醇清洗、盐酸清洗等不同前处理工艺对材料包覆性能的影响。根据抗氧化性实验结果,发现盐酸清洗的前处理工艺可以得到热稳定性相对良好的复合材料,使得氧化起始温度推迟达110℃左右。通过体积电阻率的测量,发现包覆后的材料导电性有所减弱。然后进一步讨论了不同粒径铜粉的原子层沉积包覆结果,结果显示小粒径的材料需要较大的前驱体压力才能实现颗粒良好包覆。由于原子层沉积技术成膜质量好、重复性佳以及厚度精确可控等特点,可以将其应用于粉体的改性领域。
[Abstract]:Atomic Layer deposition (ALD) is an advanced coating process, which has been widely used in semiconductor, microelectronics and other fields.However, there are few reports on this technology in the field of ultrafine metal powder.Due to the high surface activity of ultrafine metal powder, copper powder and iron powder can be oxidized easily in high temperature and wet environment, which will damage many excellent properties of materials, so it is necessary to solve the problem of oxidation in the process of application.The purpose of this paper is to improve the oxidation resistance of iron powder and copper powder and to improve the absorbing property of carbonyl iron powder by atomic layer deposition technology, and to explore the application prospect of atomic layer deposition technology in the modification of powder.By adjusting the process parameters of ALD reaction, the effects of different process conditions on the coating materials were investigated, and the appropriate process conditions were finally determined.The carbonyl iron powders of 25-50-75 ALD cycle were further prepared. The results of SEM and TEM analysis showed that the aluminum oxide thin layer was compact and uniform, and it had good contact with the surface of the particles, and the profile of the coating material was clearly visible.The results show that the coated carbonyl iron powder has excellent oxidation resistance and increases with the increase of the number of coating cycles.The corrosion test of hydrochloric acid shows that the coated material has good corrosion resistance.The electromagnetic properties of carbonyl iron powder before and after modification were systematically analyzed by means of vector network analyzer. The results showed that the dielectric constant decreased significantly and the change of magnetic permeability was relatively small after modification, which improved the electromagnetic parameters of the original iron carbonyl powder.The impedance matching property of the material was improved. The atomic layer deposition technique was used for the first time. The surface of fine copper powder was coated with trimethyl aluminum and water for the first time. The direct coating and isopropanol cleaning were studied.Effects of different pretreatment processes such as hydrochloric acid cleaning on coating properties of materials.According to the experimental results of oxidation resistance, it was found that the pretreated process of hydrochloric acid cleaning could obtain composites with relatively good thermal stability, which delayed the starting temperature of oxidation by about 110 鈩，

本文编号：1725945