TiCN-Ti-Al2O3 Coated Cutting Tool for Chipping Resistance

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Solution Overview

Problem

Coated cutting tools experience chipping and peeling due to poor fracture resistance under severe cutting conditions, particularly with Al2O3 layers that have obtuse angles and shapes that hinder film forming properties.

Innovation Solution

A coated tool with a TiCN layer, an intermediate layer including Ti, and an Al2O3 layer, where the Al2O3 layer is positioned further away from the base and features a plurality of first protrusions with acute angles and a specific area, enhancing adhesion and film forming properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a coating layer with Al2O3 is used to improve wear resistance, then wear resistance is improved, but fracture resistance deteriorates under heavy intermittent cutting conditions

Engineering Contradiction:

Improvewear resistanceVSAvoidfracture resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The coating layer is segmented into multiple functional layers: a TiCN layer for wear resistance, an intermediate Ti layer for adhesion, and an Al2O3 layer for protection. This segmentation allows each layer to perform its specific function optimally while working together to resolve the contradiction between wear resistance and fracture resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating structure combining different materials (TiCN, Ti, Al2O3) with complementary properties. The TiCN layer provides wear resistance, the intermediate Ti layer provides ductility and adhesion, and the Al2O3 layer provides chemical stability and protection, creating a composite system that achieves both wear resistance and fracture resistance.

Inventive Principle:

Principle #40Composite materials

2Strength

If protrusions with obtuse angles are formed on the interface to improve adhesion, then adhesion is improved, but film forming properties deteriorate

Engineering Contradiction:

ImproveadhesionVSAvoidfilm forming properties

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the protrusions, specifically controlling the angle to be acute (sharper) rather than obtuse. This parameter change improves film forming properties while the dense arrangement and appropriate size control of the protrusions maintain adequate adhesion between layers.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12194543B2Coated tool and cutting tool including the same

Publication Date: 2025.01.14 KYOCERA CORP

AI summary

A coated tool in the present disclosure includes a base and a coating layer located on a surface of the base. The coating layer includes a TiCN layer, an intermediate layer including Ti, and an Al2O3 layer in this order from a side of the base. The Al2O3 layer is located in contact with the intermediate layer at a position further away from the base than the intermediate layer. The intermediate layer includes a plurality of first protrusions protruding toward the Al2O3 layer. An average area of the plurality of first protrusions is 1700 nm2 or less. A cutting tool in the present disclosure includes a holder which is extended from a first end toward a second end and includes a pocket on a side of the first end, and the coated tool located in the pocket.