Synthesis of High Aspect Ratio Silica Nanoparticles and their Application in Chemical Mechanical Polishing of Zirconia Ceramics

Premium-quality zirconia ceramics are one of the promising back panel materials in 5 G mobile phone manufacturing, and nano abrasive particles play a crucial role in the chemical mechanical polishing (CMP) of zirconia ceramics. This work introduces a novel synthesis route for non-spherical silica nanoparticles (NSNPs) with a high aspect ratio through the self-assembly of spherical silica nanoparticles (SSNPs). The NSNPs have distinctive advantages in the processing of zirconia ceramics. L-lysine and CaCl 2 were employed to control the self-assembly process by adjusting electrostatic interaction and spatial repulsion between spherical nano silica seeds. Scanning electron microscopy data indicated that silica nanoparticles with varying aspect ratios (for example: peanut-like, and worm-like shapes) can be obtained by altering the amounts of L-lysine and CaCl 2 in the synthesis process. Using worm-like colloid silica with a high aspect ratio for CMP of zirconia ceramic sheets achieved an ultra-low surface roughness of 2.18 nm and a fast material removal rate of 219.48 nm h −1 , which is 300% higher than that of SSNPs. Dynamic friction coefficient and contact angle tests revealed enhanced mechanical action between NSNPs and zirconia ceramic sheets. X-ray photoelectron spectroscopy analysis showed that ZrSiO 4 was formed between silica abrasive and zirconia ceramic during the CMP process.