Two-Step Polishing for Super-Hard Material Surface Defects
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Solution Overview
Problem
Conventional polishing methods for super-hard materials like single crystal silicon carbide often leave residual scratches and fail to detect or remove minute defects, limiting the achievable surface quality.
Innovation Solution
A two-step polishing method involving preliminary polishing with a composition containing alumina particles and a polishing aid, followed by final polishing with silica particles or without abrasives, to achieve a surface roughness of 0.1 nm or less and remove latent defects, ensuring excellent smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diamond abrasives are used for lapping super-hard material substrates, then the substrate surface can be smoothed, but residual scratches are left and surface smoothness is limited
Solution Approach 1:
The polishing process is divided into multiple sequential steps with different polishing compositions having progressively finer abrasive particles. The first polishing step uses a coarser composition to remove scratches, while subsequent steps use finer compositions to eliminate residual defects, achieving progressively higher surface smoothness without leaving harmful scratches.
Solution Approach 2:
The invention changes the particle size parameter of abrasives across different polishing steps. By using polishing compositions with progressively smaller abrasive particles (from the first polishing step to subsequent steps), the process transitions from removing large scratches to eliminating fine residual defects, thereby resolving the contradiction between initial smoothing and residual scratch removal.
2Manufacturing precision
If a single polishing step is used, then the process is simple, but minute defects like latent defects cannot be precisely eliminated
Solution Approach 1:
The polishing process is segmented into multiple steps, each targeting different defect scales. The first polishing step addresses larger surface irregularities and scratches, while the second polishing step specifically targets minute latent defects. This segmentation enables precise defect elimination that would be unachievable in a single step, justifying the increased process complexity.
Solution Approach 2:
The first polishing step performs preliminary action by removing larger surface defects and preparing the substrate surface. This preliminary polishing creates a foundation that enables the second polishing step to effectively target and eliminate remaining latent defects, achieving high precision defect removal through staged preparation.
3Manufacturing precision
If conventional polishing methods are used, then the process is straightforward, but the achievable surface quality level is limited
Solution Approach 1:
The polishing process is divided into specialized steps where each composition is optimized for specific surface conditions. The first polishing composition efficiently removes scratches and larger defects, while the second polishing composition is optimized for eliminating latent defects and achieving atomic-level smoothness. This segmentation achieves superior surface quality that would take much longer with conventional single-step methods.
Solution Approach 2:
The invention changes multiple parameters across polishing steps including abrasive particle size, composition chemistry, and polishing conditions. By optimizing these parameters for each specific polishing objective, the process achieves dramatically higher surface quality levels more efficiently than conventional methods, reducing the time needed to reach atomic-level smoothness.
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 method effectively eliminates latent defects and improves surface smoothness, achieving a higher level of surface quality by precisely removing minute defects that are difficult to detect with standard inspection devices.
Implementation Method 1
a step of carrying out preliminary polishing on the substrate using a preliminary polishing composition; and a step of carrying out final polishing on the preliminarily polished substrate using a final polishing composition
Data Source
AI summary
Provided is a polishing method that can efficiently achieve a surface of a super-hard material from which latent defects are precisely eliminated. The polishing method provided by the present invention is used for polishing a substrate made of a material having a Vickers hardness of 1500 Hv or higher. The polishing method includes: a step of carrying out preliminary polishing on the substrate using a preliminary polishing composition; and a step of carrying out final polishing on the preliminarily polished substrate using a final polishing composition. Here, a surface roughness RaPRE of the preliminarily polished substrate measured by an AFM is 0.1 nm or less, and a polishing removal in the final polishing step is 0.3 µm or more.