Diamond Coating Composition for Wear-Resistant Cutting Tools
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Solution Overview
Problem
Diamond-coated tools experience reduced lifetime due to wear of the coating, necessitating a solution for enhanced wear resistance and longer tool life.
Innovation Solution
A diamond-coated tool with a diamond layer having specific boron and oxygen content gradients, including a first region with 1×10^3 to 1×10^6 ppma boron and 1×10^2 to 1×10^5 ppma oxygen, and a second region with reduced boron content for improved adhesion, and an alternating layer structure for enhanced wear resistance and lubricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diamond coating film is doped with boron to improve oxidation resistance and lubricity, then the wear resistance is improved, but the adhesion to the base material deteriorates
Solution Approach 1:
The patent applies local quality by creating a boron concentration gradient within the diamond coating film. The surface region contains higher boron concentration (1×10³ to 1×10⁶ ppma) for improved oxidation resistance and lubricity, while the region near the base material contains lower boron concentration (1×10² to 1×10⁵ ppma) for better adhesion. This spatial variation in composition resolves the contradiction between wear resistance and adhesion.
Solution Approach 2:
The patent segments the diamond coating film into multiple regions with different boron concentrations. The coating is divided into a surface region (0 to 1 μm from surface) and a base material region (1 μm to substrate interface), with intermediate transition zones. This segmentation allows each region to be optimized for its specific function: wear resistance at the surface and adhesion at the interface.
2Reliability
If the boron content in the diamond coating film is increased to improve oxidation resistance, then the lubricity is improved, but the adhesion to the base material deteriorates
Solution Approach 1:
The patent implements local quality by establishing a boron concentration gradient where the surface region (0 to 1 μm from surface) contains high boron content (1×10³ to 1×10⁶ ppma) for enhanced oxidation resistance and lubricity, while the region adjacent to the base material contains low boron content (1×10² to 1×10⁵ ppma) for improved adhesion. This localized compositional control resolves the contradiction between oxidation resistance and adhesion.
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 tool exhibits excellent wear resistance and extended lifetime, with improved adhesion and reduced cutting resistance due to the strategic distribution of boron and oxygen in the diamond layer.
Implementation Method 1
Since the establishment of the technology of manufacturing diamond thin films by chemical vapor deposition (hereinafter also referred to as a CVD) in the 1980's
Implementation Method 2
There has been known a technique for improving the oxidation resistance and the lubricity of a diamond coating film by doping the diamond coating film with boron
Data Source
AI summary
A diamond coated tool includes a base material and a diamond layer provided on the base material. The diamond layer has a boron content of 1×103 ppma or more and 1×106 ppma or less and an oxygen content of 1×102 ppma or more and 1×105 ppma or less in a first region surrounded by a surface of the diamond layer and a first imaginary plane located at a distance of 1 μm from the surface in a thickness direction.