Al-Rich Multilayer Cutting Tool Coating for Severe Wear Conditions
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Solution Overview
Problem
Conventional coated cutting tools with hard coating films face durability issues in severe usage environments, particularly when machining high hardness steels with high efficiency, as they tend to suffer from damage and wear.
Innovation Solution
A coated cutting tool design featuring a substrate with a hard coating film comprising specific layers: a nitride or carbonitride layer rich in aluminum, a layered coating film with alternating Al-rich AlCrN and AlTiN layers, and a TiSiN-based layer, optimized to enhance adhesion, heat resistance, and wear resistance, with a thickness ratio that prioritizes the layered coating film for maximum durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hard coating film with high hardness is provided on the upper layer of the conventional layered coating film, then wear resistance is improved, but damage to the tool increases in severe usage environments
Solution Approach 1:
The patent applies composite materials by creating a multi-layer coating structure combining Al-rich nitride/carbonitride layers with a TiSiN-based hard layer. The Al-rich layers provide toughness and adhesion, while the TiSiN layer provides hardness, creating a composite coating system that balances wear resistance and damage resistance in severe machining environments.
Solution Approach 2:
The patent implements local quality by assigning different functional properties to different layers of the coating. The Al-rich nitride/carbonitride layers are positioned to provide adhesion and toughness at the interface with the substrate and between layers, while the TiSiN-based layer is positioned at the surface to provide wear resistance, with each layer optimized for its specific function.
2Reliability
If a layered coating film with alternating AlCrN and AlTiN layers is used, then adhesion and heat resistance are improved, but the coating complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the coating into distinct functional layers: an Al-rich nitride/carbonitride layer and a TiSiN-based hard layer, with the Al-rich layer itself segmented into alternating AlCrN and AlTiN sub-layers. This segmentation allows each layer to be optimized for specific functions while maintaining overall coating performance.
3Reliability
If the layered coating film thickness is increased to improve durability, then wear resistance improves, but the overall coating thickness increases
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness ratio between the Al-rich nitride/carbonitride layer and the TiSiN-based hard layer. By adjusting these thickness parameters within specific ranges, the coating achieves maximum durability while controlling the overall thickness, with the Al-rich layer thickness being 0.1-5.0 μm and the TiSiN layer thickness being 0.1-5.0 μm.
Data Source
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AI summary
Provided is a coated cutting tool, which includes a hard coating film containing a layer (c) which is a layered coating film made by alternately layering a nitride or carbonitride layer (c1) that contains, with respect to the total amount of metal elements (including metalloid elements), at least 55 atom% aluminum (Al), chromium (Cr) having the second highest content percentage, and at least silicon (Si), and a nitride or carbonitride layer (c2) that contains, with respect to the total amount of metal elements (including metalloid elements), at least 55 atom% aluminum (Al) and titanium (Ti) having the second highest content, each layer having a thickness of 50 nm or less. A peak intensity Ih ascribable to an hcp (010) plane of AlN in the layer (c) and the total peak intensity Is ascribable to other predetermined crystal phases satisfy a relationship of Ih× 100/Is ≤ 15.