TiCN Coated Cutting Tool Crystal Structure
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Solution Overview
Problem
Conventional surface-coated cutting tools with TiCN layers face issues of insufficient wear resistance during continuous cutting and chipping resistance during intermittent cutting, particularly when cutting cast iron, due to peeling of the coating film and lack of hardness.
Innovation Solution
A surface-coated cutting tool with a TiCN layer having a columnar crystal region and a specific atomic ratio of carbon to nitrogen (0.70 ≤ x/(x + y) ≤ 0.89) and a (422) plane spacing of 0.8767 Å to 0.8787 Å, combined with an alumina layer, is used, which enhances both wear and chipping resistance by improving adherence and strain within the crystal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the atomic ratio of carbon to the sum of carbon and nitrogen in the TiCN layer is increased to improve wear resistance, then wear resistance is improved, but the coating film becomes more likely to peel off from the base material, resulting in insufficient chipping resistance
Solution Approach 1:
The invention changes the crystallographic parameter (plane spacing of (422) plane) and composition parameters (atomic ratio of C to N) of the TiCN layer to achieve optimal performance. By controlling the plane spacing to 0.8759 Å to 0.8787 Å and the atomic ratio to 0.70 ≤ x/(x+y) ≤ 0.89, the coating achieves both high wear resistance and chipping resistance without peeling.
2Reliability
If a specific inclination angle distribution of crystal plane is provided to improve chipping resistance, then chipping resistance is improved, but the coating film cannot be highly hardened, resulting in insufficient wear resistance
Solution Approach 1:
The invention changes the crystallographic parameter from inclination angle distribution to plane spacing of the (422) plane. By controlling the plane spacing to 0.8759 Å to 0.8787 Å, the coating achieves both high chipping resistance and high wear resistance simultaneously, overcoming the limitation of conventional inclination angle control methods.
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 solution significantly improves wear resistance and chipping resistance, preventing peeling and maintaining effectiveness during both continuous and intermittent cutting processes, while maintaining sufficient hardness to prevent brittleness.
Implementation Method 1
The TiCN layer has a columnar crystal region with a composition of TiC x N y (in which 0.70 ≤ x/(x + y) ≤ 0.89) and has a (422) plane having a plane spacing of 0.8767 Å to 0.8787 Å
Data Source
AI summary
A surface-coated cutting tool according to the present invention includes a base material and a coating film formed on the base material. The coating film includes at least one TiCN layer. The TiCN layer has a columnar crystal region. The columnar crystal region is characterized by having a composition of TiCxNy (in which 0.65 ≤ x/(x + y) ≤ 0.90) and having a (422) plane having a plane spacing of 0.8765 Å to 0.8790 Å.