Cutting Plate Boron Nitride Adhesion Layer
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Solution Overview
Problem
Existing cutting tips face challenges in achieving strong adhesive strength and durability, particularly under impact loads, due to differences in thermal expansion coefficients and residual stresses between hard metal and diamond layers.
Innovation Solution
A cutting tip with a base body made of sintered hard metal and an adhesion-promoting layer of boron-containing nitrides, featuring vertically oriented columnar diamond crystals, which provides mechanical interlocking and chemical bonding, enhancing adhesive strength and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diamond layer is deposited on a hard metal base body, then cutting performance is improved, but adhesion strength deteriorates due to differences in thermal expansion coefficients and residual stresses
Solution Approach 1:
An intermediate layer comprising boron-containing nitride platelets of a transition metal is deposited between the diamond layer and the hard metal base body. This intermediate layer acts as a mediator that accommodates the thermal expansion coefficient difference between diamond and hard metal, reducing residual stresses while providing mechanical interlocking through its platelet structure and chemical bonding to both layers.
Solution Approach 2:
The coating structure employs a composite material system with distinct layers: a hard metal base body, an intermediate layer of boron-containing nitride platelets, and a diamond layer. This composite structure combines materials with different properties to achieve both hard cutting performance and stress management, where each layer contributes specific characteristics to the overall system performance.
2Duration of action of stationary object
If the diamond layer is made thicker to improve cutting durability, then cutting edge longevity is improved, but adhesion strength deteriorates due to increased residual stresses
Solution Approach 1:
The intermediate layer of boron-containing nitride platelets serves as a stress-absorbing mediator that enables the deposition of thicker diamond layers without compromising adhesion. The platelet structure provides mechanical interlocking and the boron-containing compounds facilitate stress distribution, allowing the diamond layer to achieve greater thickness for improved durability while maintaining strong bonding to the base body.
3Reliability
If conventional intermediate layers are used, then manufacturing simplicity is maintained, but adhesion strength deteriorates under impact loading
Solution Approach 1:
The invention changes the chemical composition parameters of the intermediate layer by incorporating boron-containing nitrides of transition metals. This compositional modification transforms the intermediate layer into a material that provides both mechanical interlocking through its platelet structure and enhanced chemical bonding capability, significantly improving impact resistance while remaining compatible with existing CVD manufacturing processes.
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 solution achieves a robust and impact-resistant connection between the diamond layer and the base body, ensuring the cutting tip's mechanical stability and preventing chipping, even under high stress conditions.
Implementation Method 1
the mechanical interlocking with the platelet-structured diamond layer and the good chemical bond result in very good adhesion strength
Implementation Method 2
the boron-containing platelet structure enables stable bonding of the columnar crystals of the diamond layer
Implementation Method 3
One or more intermediate layers (25), including an adhesion promoter layer (26), are deposited onto a top surface (23) of the base body (22) by means of a continuous vapor deposition (CVD) process
Implementation Method 4
growth of the diamond layer (24) on the adhesion layer (26) comprises the following steps: germination of the adhesion layer (26) with diamond dust and growth of stem-shaped diamonds from the gas phase on the adhesion layer (26)
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to a cutting plate (12) having a base (22) made of a sintered hard metal. On an upper side (23) of the base (22) there are one or more intermediate layers (25), which have an adhesion promoting layer (26). The adhesion promoting layer (26) is made of a boron-containing nitride of a transition metal of group IV, group V, and group VI, and contains a plurality of platelets (31) oriented at an angle relative to the upper side (23). A diamond layer that is grown on the adhesion promoting layer (26) has stalk-like crystals oriented vertically relative to the upper side (23), the aspect ratio of which is greater than three.