Nitride-Bonded PCBN Material Without WC-Co Backing
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Solution Overview
Problem
Existing machining tools face challenges when working with extreme conditions, particularly with heat-resistant superalloys like Inconel™, as they often rely on Critical Raw Materials such as tungsten and cobalt, which are scarce and strategically important, and require a WC-Co backing that is not always necessary or efficient.
Innovation Solution
Development of a polycrystalline cubic boron nitride (PCBN) material comprising 40-95 vol.% cubic boron nitride particles with a binder matrix of aluminium or titanium compounds, and optionally including oxynitride and oxide compounds, which is produced by milling precursor powders and sintering them at high pressures and temperatures to create a viable alternative for tooling operations without the need for a WC-Co backing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If WC-Co backing is used in machining tools, then mechanical strength and structural stability are improved, but dependence on critical raw materials (tungsten, cobalt) increases and strategic vulnerability worsens
Solution Approach 1:
The patent extracts and removes the WC-Co backing component from the tool structure, replacing it with a substrateless PCBN design. This eliminates dependence on critical raw materials (tungsten, cobalt) while maintaining structural integrity through the inherent strength of sintered cubic boron nitride particles bonded directly to each other
Solution Approach 2:
The patent uses composite PCBN material consisting of cubic boron nitride particles bonded together through sintering, creating a self-supporting structure that eliminates the need for separate backing materials. The composite nature of PCBN provides both the mechanical strength previously requiring WC-Co backing and freedom from critical material dependencies
2Strength
If traditional sintering methods are used, then material density and hardness are improved, but processing time and energy consumption increase
Solution Approach 1:
The patent applies preliminary classification and preparation of PCBN particles before sintering, ensuring optimal particle size distribution and morphology. This preliminary action enables more efficient sintering with reduced time and energy requirements while achieving the desired hardness and density, as properly prepared particles sinter more effectively
Solution Approach 2:
The patent optimizes sintering parameters including temperature, pressure, and atmosphere conditions to achieve maximum hardness with minimum processing time. By carefully controlling these parameters, the sintering process achieves rapid densification and bonding while maintaining the ultra-hard properties of PCBN material
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 PCBN material effectively performs in extreme conditions, offering superior machining capabilities for heat-resistant superalloys like Inconel™, with improved hardness and reduced wear rates, and serves as a sustainable alternative to materials like cemented carbides, demonstrating enhanced durability and efficiency in machining operations.
Implementation Method 1
subjected to high pressure and high temperature so that inter-grain bonding between the diamond grains or CBN grains occurs, forming a polycrystalline super hard diamond or polycrystalline CBN layer
Implementation Method 2
ball milled to break down the matrix precursor powders to a desired size (typically 50 nm to 700 nm) and to intimately mix the matrix precursor powders with the cBN particles
Implementation Method 3
The dried powder is sieved and a pre-composite assembly is prepared. The pre-composite assembly is heat treated at above 700° C. to remove any adsorbed water or gases
Data Source
AI summary
This disclosure relates to a polycrystalline cubic boron nitride, PCBN, material that includes a binder matrix material containing nitride compounds. The nitride compounds are selected from HfN, VN, and/or NbN.