TiCNO-Al2O3 Coating Structure for Chipping-Resistant Cutting Tools
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Solution Overview
Problem
Cutting tools with Al2O3 coatings face issues with chipping and peeling under heavy intermittent cutting conditions due to insufficient fracture resistance, which existing techniques have not adequately addressed.
Innovation Solution
A coated tool design featuring a TiCNO layer with first and second composite protrusions that project towards and intersect with the Al2O3 layer, enhancing adhesion and fracture resistance by maintaining homogeneous compositions and specific structural features, such as dimensions and orientations, to prevent peeling and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating layer with Al2O3 is formed on a base member through a bonding film to improve wear resistance, then wear resistance is improved, but fracture resistance deteriorates under heavy intermittent cutting conditions
Solution Approach 1:
The invention introduces a specific layer structure with a TiCNO layer containing first and second composite protrusions at the interface between the TiCNO layer and Al2O3 layer. These protrusions create localized structural features that enhance adhesion and fracture resistance at critical stress points, while the rest of the coating maintains its wear-resistant properties.
Solution Approach 2:
The invention uses a composite coating structure consisting of multiple layers (bonding film, TiCNO layer, Al2O3 layer) with specific interfacial features. The TiCNO layer with composite protrusions acts as an intermediate structure that combines the properties of both the bonding film and Al2O3 layer, improving overall coating performance under impact conditions.
2Reliability
If the coating layer is designed to prevent peeling under impact, then adhesion is improved, but the complexity of the coating structure increases
Solution Approach 1:
The TiCNO layer is segmented into distinct regions with first composite protrusions extending toward the Al2O3 layer and second composite protrusions extending toward the bonding film. This segmentation creates multiple adhesion zones that improve bonding without requiring a completely complex multi-layer structure.
Solution Approach 2:
The coating structure employs a nested layer configuration where the bonding film is at the base, followed by the TiCNO layer with its composite protrusions, and finally the Al2O3 layer on top. The composite protrusions nest within the TiCNO layer structure, creating a compact yet effective design that improves adhesion without excessive complexity.
Data Source
AI summary
A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al2O3 layer. The Al2O3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a first composite protrusion including a first protrusion that projects toward the Al2O3 layer and a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects. A cutting tool of the present disclosure is provided with: a holder extending from a first end toward a second end and including a pocket on a side of the first end; and the above-described coated tool located in the pocket.