Core-Shell Cermet Composition for Wear and Chipping Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cermet cutting tools face challenges in achieving a balance between wear resistance and chipping resistance due to insufficient binding force at the interface between the hard phase and the binder phase, and the presence of Mo lowers resistance against adhesion to steel, affecting chipping performance.
Innovation Solution
A cermet composition featuring a hard phase with a core portion of composite carbonitride expressed as Ti1-X-Y NbX WY C1-Z NZ, where X is between 0.1 and 0.6, and a peripheral portion with higher W content, along with a metallic binder phase containing an iron-group element, enhances binding force and mechanical strength, while controlling the content of WC and impurities like V and Mo to prevent adhesion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a composite carbonitride solid solution (Ti1-xMx)(C1-yNy) with M=W, Mo, Nb, Zr, or Ta is used in the hard phase, then wear resistance is improved, but binding force at the interface between hard phase and binder phase becomes insufficient
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core portion contains composite carbonitride (Ti1-x-yLxMoy)(C1-zNz) and the peripheral portion contains different carbonitride composition. This allows different regions to have optimized properties: the core provides wear resistance while the peripheral portion enhances binding force at the interface with the binder phase, thus resolving the contradiction between wear resistance and interface binding strength.
Solution Approach 2:
The patent uses composite materials by combining multiple carbonitride phases with different compositions within the same hard phase structure. The first hard phase contains (Ti1-x-yLxMoy)(C1-zNz) while the second hard phase contains (Ti1-a-bLaMb)(C1-cNc), creating a composite structure that simultaneously achieves wear resistance and improved interface binding, resolving the technical contradiction.
2Strength
If Mo is added to the composite carbonitride solid solution, then mechanical strength is improved, but resistance against adhesion to steel decreases
Solution Approach 1:
The patent applies local quality by concentrating Mo in the core portion of the hard phase where it enhances mechanical strength, while the peripheral portion has reduced Mo content and increased W content to prevent adhesion to steel. This spatial distribution allows simultaneous achievement of high mechanical strength and low adhesion, resolving the contradiction between these two properties.
Solution Approach 2:
The patent changes the compositional parameters by defining specific ranges: Mo content in the core is controlled at 0.01≤y≤0.05, while W content is increased to 0.05≤b≤0.1 in the peripheral portion. These parameter adjustments allow optimization of both mechanical strength (through Mo in core) and adhesion resistance (through W in peripheral), resolving the technical contradiction.
Data Source
Figure 1~2
AI summary
Cermet contains a hard phase which contains carbonitride containing Ti and Nb and a metallic binder phase containing an iron-group element. The hard phase includes a granular core portion and a peripheral portion which covers at least a part of the core portion. The core portion contains composite carbonitride expressed as Ti1-X-YNbXWYC1-ZNZ, where Y is not smaller than 0 and not greater than 0.05 and Z is not smaller than 0.3 and not greater than 0.6. The peripheral portion is composed to be higher in content of W than the core portion.