PCBN Surface Borides for Thermal Crack-Resistant Cutting Tools
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Solution Overview
Problem
Conventional polycrystalline cubic boron nitride tools suffer from thermal cracking due to severe thermal cycles during cutting processes, leading to reduced strength and inability to maintain a sharp blade tip, limiting their precision and lifespan in machining high-hardness materials.
Innovation Solution
The development of polycrystalline cubic boron nitride with protrusion-shaped borides on its surface and the formation of compounds like BN, Ti, W, Co, Zr, and Si during sintering, enhancing bonding strength with binders, along with a surface treatment and sintering process at specific temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polycrystalline cubic boron nitride is used for cutting high-hardness materials, then it provides adequate hardness and wear resistance, but thermal cracking occurs due to severe thermal cycles, leading to reduced strength and tool lifespan
Solution Approach 1:
The patent applies local quality by creating protrusion-shaped boride structures at specific locations on the CBN particle surfaces. These localized protrusions concentrate stress and inhibit crack propagation at critical interface regions between CBN particles and binder, thereby improving impact resistance and thermal cracking resistance without altering the overall material composition
Solution Approach 2:
The patent creates a composite structure by forming boride compounds (such as TiB2, ZrB2, WB2) at the interfaces between CBN particles and binder material. This composite approach combines the extreme hardness of CBN with the toughness of metal binders, while the interfacial boride layer enhances bonding strength and prevents thermal cracking during cutting operations
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
This approach significantly improves impact resistance and wear resistance, extending the lifespan of machining tools by inhibiting crack development and increasing bonding strength between cubic boron nitride and binders.
Implementation Method 1
a fourth step of sintering the shaped mixed powders
Implementation Method 2
producing the polycrystalline cubic boron nitride with one or more kinds of protrusion-shaped borides formed on the cubic boron nitride surface may inhibits the development of cracks along the surfaces of the cubic boron nitride particles and binders
Implementation Method 3
the polycrystalline cubic boron nitride may have at least one kind of a compound composed of at least two selected from a group consisting of BN, Ti, W, Co, Zr, and Si as formed during sintering
Data Source
AI summary
The present disclosure relates to polycrystalline cubic boron nitride (PCBN) with enhanced impact-resistance and wear-resistance and a method for producing the PCBN. According to the present disclosure, producing the polycrystalline cubic boron nitride with one or more kinds of protrusion-shaped borides formed on the cubic boron nitride surface may inhibits the development of cracks along the surfaces of the cubic boron nitride particles and binders, thereby to improve the impact-resistance and wear-resistance. In this way, the life-span of the machining tools may be enhanced. Further, the polycrystalline cubic boron nitride may have at least one kind of a compound composed of at least two selected from the group consisting of BN, Ti, W, Co, Zr, and Si as formed during sintering. This may allow the PCBN to have high bonding strength between the cubic boron nitride and the binder.