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 inadequate fracture resistance, which existing techniques have not adequately addressed.

Innovation Solution

A coated tool design featuring a TiCNO layer with composite protrusions (first, second, and third protrusions) of homogeneous composition, formed using specific chemical vapor deposition conditions, enhances the adhesion between the TiCNO and Al2O3 layers, improving fracture resistance and preventing peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a bonding film and Al2O3 layer are formed sequentially with dendrite structures, then adhesion between layers is enhanced, but the coating layer still experiences chipping and peeling under heavy intermittent cutting conditions

Engineering Contradiction:
Improveadhesion between bonding film and Al2O3 layerVSAvoidfracture resistance of coating layer
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The coating layer is divided into multiple functional layers: a bonding film with dendrite structures for adhesion, an intermediate Al2O3 layer for wear resistance, and a surface layer with specific crystal orientation for fracture resistance. This segmentation allows each layer to specialize in one function, resolving the contradiction between adhesion and fracture resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses composite material structures combining different materials (bonding film material, Al2O3, and surface layer material) with specific microstructures (dendrites, columnar crystals) to achieve both strong adhesion and high fracture resistance. The composite structure allows the bonding film to provide adhesion while the Al2O3 and surface layers provide fracture resistance.

Inventive Principle:
Principle #40Composite materials

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 coated tool exhibits enhanced adhesion strength and reduced likelihood of peeling, maintaining performance under severe cutting conditions with improved fracture resistance and wear resistance.

Implementation Method 1

a coating layer formed by laminating an Al 2 O 3 layer is formed on a surface of a base member such as a cemented carbide, a cermet or a ceramic through a bonding film

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP3747575B1Coated tool, and cutting tool comprising same
Publication Date: 2024.01.31 KYOCERA CORP
  • EP3747575B1 patent drawingFigure 1
  • EP3747575B1 patent drawingFigure 2
  • EP3747575B1 patent drawingFigure 3

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 composite protrusion including a first protrusion that projects toward the Al2O3 layer, a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects, and a third protrusion that projects from the second protrusion in a direction intersecting the direction in which the second 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.