cBN Sintered Material With Oxygen-Rich Interfaces for Tool Life
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Solution Overview
Problem
The rapid improvement in mechanical parts has made it difficult to cut workpieces, leading to a short life of cutting tools and increased costs, necessitating a more durable cubic boron nitride sintered material.
Innovation Solution
A cubic boron nitride sintered material with a composition of more than 50 volume % and less than 80 volume % of cubic boron nitride grains, and more than 20 volume % and less than or equal to 50 volume % of a binder phase, where the binder phase includes compounds from group 4, 5, and 6 elements, nitrogen, carbon, boron, and oxygen, with specific oxygen content and interface characteristics to enhance binding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the content ratio of cubic boron nitride grains is increased to improve hardness, then the material becomes more brittle and tool life decreases
Solution Approach 1:
The patent optimizes the content ratio parameters of cBN grains (50-80 vol%) and binder phase (20-50 vol%) to achieve the best balance between hardness and toughness. It also controls the oxygen content in the interface region (0.1-10 nm thickness with higher oxygen concentration) to enhance binding strength without compromising the overall hardness of the material.
Solution Approach 2:
The patent creates a localized oxygen-enriched interface region between cBN grains with a thickness of 0.1-10 nm. This local modification of chemical composition at the grain boundaries enhances the binding strength between grains, improving toughness and tool life while maintaining the high hardness of the bulk cBN material.
2Productivity
If conventional sintered materials are used for cutting hardened steel, then the cutting tools wear quickly and require frequent replacement
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: cBN grain content (50-80 vol%), binder phase content (20-50 vol%), and interface oxygen concentration (enriched region 0.1-10 nm thick). This multi-parameter optimization creates a material specifically tailored for cutting hardened steel, maintaining high cutting efficiency while extending tool life through enhanced grain binding.
Solution Approach 2:
The patent develops a specialized composite sintered material with a unique binder phase composition (group 4-6 elements with nitrogen, carbon, boron, or oxygen) that provides superior adhesion to cBN grains. This composite structure maintains the high hardness needed for cutting hardened steel while the optimized binder phase prevents premature tool failure, extending productive use of the cutting tool.
Data Source
AI summary
A cubic boron nitride sintered material includes: more than or equal to 50 volume % and less than 80 volume % of cubic boron nitride grains; and more than 20 volume % and less than or equal to 50 volume % of a binder phase, and when an oxygen content is measured in a direction perpendicular to an interface between cubic boron nitride grains using TEM-EDX, a first region having an oxygen content larger than an average value of an oxygen content of a cubic boron nitride grain exists, the interface exists in the first region, and a length of the first region along the direction perpendicular to the interface is more than or equal to 0.1 nm and less than or equal to 10 nm.