Abstract

SiO 2 ultrafine spheres are prepared by sol–gel method using tetraethylorthosilicate and ammonia as raw materials. CeO 2-coated SiO 2 (CeO 2@SiO 2) composite nanoparticles are also synthesized through chemical precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS) and dynamic light scattering (DLS) are used to characterize the CeO 2@SiO 2 composite particles. Silicon wafer covered by thermal oxide film is polished by CeO 2@SiO 2 composite abrasives, and the polishing behavior of novel composite abrasives is characterized by atomic force microscope (AFM). The results indicate that the phases of the as-prepared CeO 2@SiO 2 composite particles are composed of cubic fluorite CeO 2 and amorphous SiO 2. CeO 2@SiO 2 composite particles have excellent spherical morphologies and uniform particle size of 150–200 nm. The particle size of CeO 2 as shell is about 10 nm. After coating, the chemical state of SiO 2 is changed due to the formation of Si–O–Ce bond. The root-mean-square (RMS) roughness within 10 × 10 μm 2 area of thermal oxide film after polished by CeO 2@SiO 2 composite abrasives is 0.428 nm, and material removal rate can reach 454.6 nm/min.

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