The main objective of this research is to develop a technique to obtain magnetic cork particles. The magnetization is achieved by applying a coating of iron oxides, obtained directly on the surface of cork particles from an acid solution of Fe cations added to a basic solution containing the particles. Previous surface treatment of cork particles was required; hence, plasma pretreatment was applied in a vacuum chamber to clean and activate the surface, enabling the coating process. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, density and particle size were applied to characterize the cork and magnetic cork particles. In parallel, the magnetic character of particles was tested using magnets and by hysteresis cycles. All techniques have shown the presence of magnetite and maghemite on the cork surface. Results show cork particles adsorb between 17 and 27% of magnetite and maghemite, since by this process a mixture of both was obtained. These results are in accordance with density measurements. The magnetizing process is patented under Patent Numbers P201730993 and PCT/ES2018/070519.

中文翻译：

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用氧化铁涂覆软木颗粒：对磁性的影响

这项研究的主要目的是开发一种获得磁性软木颗粒的技术。磁化是通过应用氧化铁涂层实现的，铁氧化物涂层直接从软木颗粒表面获得，从添加到含有颗粒的碱性溶液中的 Fe 阳离子的酸溶液中获得。需要预先对软木颗粒进行表面处理；因此，在真空室中进行等离子体预处理以清洁和活化表面，从而实现涂层工艺。应用傅里叶变换红外光谱、X 射线衍射、扫描电子显微镜、密度和粒度来表征软木和磁性软木颗粒。同时，使用磁铁和磁滞循环来测试颗粒的磁性特性。所有技术都表明软木表面存在磁铁矿和磁赤铁矿。结果显示软木颗粒吸附了 17% 到 27% 的磁铁矿和磁赤铁矿，因为通过该过程获得了两者的混合物。这些结果与密度测量结果一致。磁化过程已获得专利，专利号为 P201730993 和 PCT/ES2018/070519。