Two-Step Polishing Composition for Smooth and Flat Super-Hard Surfaces

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Solution Overview

Problem

Conventional polishing methods for super-hard materials like silicon carbide struggle to achieve both smoothness and flatness simultaneously, often requiring a trade-off between the two due to limitations in machining power and surface finish.

Innovation Solution

A two-step polishing method using a preliminary polishing composition with a higher oxidation-reduction potential and a final polishing composition with a lower oxidation-reduction potential, along with abrasive particles of varying hardness and mean secondary particle diameter, to achieve enhanced smoothness and flatness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If polishing composition emphasizes smoothness improvement, then surface smoothness is improved, but machining power decreases and flatness deteriorates

Engineering Contradiction:
Improvesurface smoothnessVSAvoidmachining power
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The polishing process is divided into two distinct stages: preliminary polishing using a first polishing composition with higher hardness abrasive particles (5-10 μm) to maintain machining power and flatness, followed by final polishing using a second polishing composition with lower hardness abrasive particles (0.3-1 μm) to achieve smoothness. This segmentation allows each stage to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes key parameters between the two polishing compositions: the first composition uses abrasive particles with mean diameter 5-10 μm and hardness 600-800 Hv, while the second composition uses abrasive particles with mean diameter 0.3-1 μm and hardness 200-400 Hv. This parameter change enables the transition from material removal (flatness) to surface finishing (smoothness).

Inventive Principle:
Principle #35Parameter changes

2Productivity

If polishing process uses higher oxidation-reduction potential composition, then polishing speed is improved, but surface smoothness deteriorates

Engineering Contradiction:
Improvepolishing speedVSAvoidsurface smoothness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The polishing process is segmented into two sequential steps: Step 1 uses a polishing composition with high oxidation-reduction potential (800-1000 mV) to achieve fast material removal and flatness, while Step 2 uses a polishing composition with low oxidation-reduction potential (300-500 mV) to achieve smooth surface finish. This temporal segmentation resolves the contradiction between speed and smoothness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The preliminary polishing step with high oxidation-reduction potential composition prepares the surface by removing material efficiently and establishing flatness, creating a foundation for the subsequent final polishing step. This preliminary action enables the final step to focus exclusively on smoothness without compromising overall efficiency.

Inventive Principle:
Principle #10Preliminary action

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

This method efficiently achieves both smoothness and flatness on super-hard surfaces in less time compared to conventional single-step processes, overcoming the limitations of previous technologies.

Implementation Method 1

the preliminary polishing composition has an oxidation-reduction potential ORP PRE vs. standard hydrogen electrode, and the final polishing composition has an oxidation-reduction potential ORP FIN vs. standard hydrogen electrode, satisfying a relation ORP PRE > ORP FIN

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the preliminary polishing composition comprises an abrasive A PRE having a mean secondary particle diameter of 5000 nm or less

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3792000B1Polishing method and polishing composition
Publication Date: 2025.06.11 FUJIMI INCORPORATED

AI summary

Provided is a method for polishing a material having a Vickers hardness of 1500 Hv or higher. The polishing method comprises a step of carrying out preliminary polishing using a preliminary polishing composition that comprises an abrasive APRE and a step of carrying out final polishing using a final polishing composition that comprises an abrasive AFIN lower in hardness than the abrasive APRE.