cBN Coated Cutting Tool With Metal Interlayer for Adhesion
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Solution Overview
Problem
Existing coated tools face challenges in improving the adhesion between the coating film and the base body, which affects the durability and performance of the cutting tool.
Innovation Solution
A coated tool design that includes a base body made of boron nitride particles with a coating film comprising a hard layer and a metal layer, where the metal layer, such as an Al-Cr alloy, is interposed between the base body and the hard layer to enhance adhesion, and the hard layer is structured with alternating thin metal nitride layers to improve durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating film is applied directly on the base body to improve wear resistance, then the hardness and wear resistance are improved, but the adhesion between the coating film and base body deteriorates
Solution Approach 1:
A metal layer comprising at least one metal element selected from the group consisting of Zr, V, Cr, Ta, Nb, Hf, and their alloys is introduced as an intermediary between the base body and the hard layer. This metal layer serves as a bonding interface that improves adhesion between the cBN base body and the hard layer, preventing premature detachment while maintaining the wear resistance provided by the hard layer.
Solution Approach 2:
The coating structure is designed as a composite system consisting of three distinct layers: the cBN base body, the metal layer with specific metal elements, and the hard layer. This composite structure combines the advantages of each material - the hardness of cBN, the bonding capability of the metal layer, and the protective function of the hard layer - to achieve both strong adhesion and high wear resistance.
2Ease of manufacture
If the coating film structure is simplified to reduce manufacturing complexity, then the ease of manufacture is improved, but the durability and resistance to peeling and cracking deteriorate
Solution Approach 1:
The coating film is segmented into distinct functional layers: a metal layer containing specific metal elements (Zr, V, Cr, Ta, Nb, Hf or their alloys) and a hard layer. This segmentation allows each layer to perform its specific function - the metal layer provides bonding and stress management, while the hard layer provides wear protection - thereby improving durability without significantly complicating the manufacturing process.
3Reliability
If a metal layer with specific metal elements is introduced between the base body and hard layer to improve adhesion, then the adhesion and durability are improved, but the device complexity increases
Solution Approach 1:
The invention specifies particular metal elements (Zr, V, Cr, Ta, Nb, Hf or their alloys) with defined compositional parameters for the metal layer. By controlling the chemical composition within these specific parameters, the patent achieves optimal adhesion and durability properties while maintaining a relatively simple two-layer structure, thus balancing performance improvement with structural simplicity.
Data Source
AI summary
A coated tool according to the present disclosure comprises a base body and a coating film. The base body contains a plurality of boron nitride particles. The coating film is located on the base body. Furthermore, the coating film includes a hard layer and a metal layer other than a simple substance of Ti, Zr, V, Cr, Ta, Nb, Hf, and Al located between the base body and the hard layer.