AlTiN Composite Coating Structure for Wear-Resistant Cutting Tools
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Solution Overview
Problem
Conventional cutting tools experience wear and breakage due to high temperature and stress during cutting operations, necessitating improved breakage and wear resistance for enhanced cutting performance.
Innovation Solution
A surface-coated cutting tool with a hard coating layer comprising a domain region and a matrix region, where the domain region consists of alternating layers of AlTi compounds with specific crystal structures and atomic ratios, and the matrix region consists of additional AlTi compounds, applied using a CVD method involving aluminum and titanium halide gases and ammonia at controlled temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating film composed of AlTiN is used to improve hardness and oxidation resistance, then the cutting tool life is extended, but the coating film may still suffer from wear and breakage under severe cutting conditions
Solution Approach 1:
The patent applies composite materials by creating a coating film with a dual-phase structure consisting of domain regions (with hexagonal and cubic AlTi compounds) dispersed in a matrix region (with cubic AlTi compounds). This composite structure combines the high hardness and oxidation resistance of hexagonal AlTiN with the toughness and ductility of cubic AlTiN, resulting in superior wear and breakage resistance while extending cutting tool life.
Solution Approach 2:
The patent implements local quality by creating distinct domain regions with specific crystal structures (hexagonal and cubic AlTi compounds) distributed within the matrix region. The domain regions provide localized high hardness and oxidation resistance, while the matrix region provides toughness and ductility. This spatial differentiation of material properties allows the coating to simultaneously resist wear and breakage under severe cutting conditions.
2Productivity
If the cutting tool is designed to withstand high temperature and high stress, then the cutting performance is improved, but the complexity of the coating structure increases
Solution Approach 1:
The patent applies parameter changes by controlling the crystal structure (hexagonal vs. cubic), composition ratios (x1, x2, x3, x4 values), and layering arrangement of AlTi compounds during the CVD process. By adjusting these parameters, the coating achieves optimal balance between hardness, oxidation resistance, and toughness, enabling the cutting tool to withstand high temperature and stress while maintaining manageable structural complexity through systematic parameter control.
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 surface-coated cutting tool exhibits excellent breakage resistance, wear resistance, and chipping resistance, extending tool life and maintaining performance under high-stress cutting conditions.
Implementation Method 1
emitting first gas, second gas, and third gas to the substrate in an atmosphere at more than or equal to 650° C. and less than or equal to 900° C. and under more than or equal to 0.5 kPa and less than or equal to 5 kPa, the first gas including aluminum halide gas and titanium halide gas, the second gas including aluminum halide gas, titanium halide gas, and ammonia gas, the third gas including ammonia gas
Data Source
AI summary
A surface-coated cutting tool includes a substrate and a coating film that coats the substrate, wherein the coating film includes a hard coating layer constituted of a domain region and a matrix region, the domain region is a region having a plurality of portions divided and distributed in the matrix region, the domain region has a structure in which a first layer composed of a first Alx1Ti(1-x1) compound and a second layer composed of a second Alx2Ti(1-x2) compound are layered on each other, the matrix region has a structure in which a third layer composed of a third Alx3Ti(1-x3) compound and a fourth layer composed of a fourth Alx4Ti(1-x4) compound are layered on each other.