Spherical Cerium Oxide Abrasive for Scratch-Free Polishing
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Solution Overview
Problem
Current cerium oxide abrasive materials used for polishing glass optical elements and semiconductor devices have irregular surfaces, leading to scratches and reduced productivity due to their non-spherical shape and insufficient polishing rate, despite efforts to increase trivalent cerium content for enhanced polishing performance.
Innovation Solution
Development of cerium oxide abrasive materials with spherical cerium oxide particles produced using an aqueous solution of a rare earth element salt and a precipitant, with controlled aspect ratio, trivalent cerium content, and firing conditions to achieve high polishing performance and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cerium oxide abrasive particles are prepared by a pulverization process to increase polishing rate, then the polishing rate is improved, but the particles have sharply edged surfaces that scratch workpiece surfaces
Solution Approach 1:
The patent applies spheroidality by preparing cerium oxide abrasive particles with a spherical shape through a controlled precipitation process rather than pulverization. The spherical morphology eliminates sharp edges that cause scratching, while maintaining high polishing rate through optimized particle composition and surface properties.
2Manufacturing precision
If a multi-stage polishing process is used with colloidal silica to improve surface smoothness, then the surface roughness is reduced, but the productivity is reduced
Solution Approach 1:
The patent merges the functions of primary polishing (high polishing rate) and secondary polishing (surface smoothness) into a single stage by developing spherical cerium oxide particles that simultaneously provide high material removal rate and low scratching tendency, eliminating the need for separate colloidal silica polishing step.
Solution Approach 2:
The patent changes the particle morphology parameter from irregular/pulverized shape to spherical shape, and optimizes the particle size distribution and composition parameters to achieve both high polishing rate and surface smoothness in a single polishing process.
3Shape
If other rare earth elements are added to adjust particle shape and size distribution, then the particle morphology is improved, but the cerium concentration on particle surfaces is reduced
Solution Approach 1:
The patent extracts and removes other rare earth elements from the particle composition, using only cerium oxide to maintain high cerium concentration on the particle surface. The spherical shape and controlled size distribution are achieved through precipitation process parameters rather than compositional modification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting cerium oxide abrasive material achieves high polishing rates and surface smoothness with reduced scratches, improving productivity and maintaining high sphericity, thereby addressing the limitations of traditional cerium oxide abrasive materials.
Implementation Method 1
adding an aqueous solution of a precipitant to an aqueous solution of a salt of a rare earth element and heating the solution with stirring to prepare a precursor of abrasive particles
Implementation Method 2
firing the precursor to form cerium oxide abrasive particles
Data Source
AI summary
An object of the present invention is to provide a cerium oxide abrasive material containing cerium oxide abrasive particles prepared by a synthetic method using an aqueous solution of a salt of a rare earth element and a precipitant, the cerium oxide abrasive particles having a spherical shape and high polishing performance (polishing rate and polishing precision of the polished surface), a method for producing the cerium oxide abrasive material, and a polishing method. The cerium oxide abrasive material according to the present invention comprises spherical cerium oxide abrasive particles prepared by a synthetic method using an aqueous solution of a salt of a rare earth element and a precipitant, wherein the cerium oxide abrasive particles have a spherical shape having an average aspect ratio within the range of 1.00 to 1.15.