FeNi Binder Alloy for Cobalt-Free Hard Metals
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Solution Overview
Problem
Current hard metals using Ni-, FeNi-, or FeCoNi-based binder alloys lack universal applicability due to low hardness, hot hardness, and fracture toughness compared to cobalt-based alloys, and pose health hazards, necessitating a replacement for cobalt with safer alternatives that maintain or exceed cobalt's properties.
Innovation Solution
A sintered composite material is produced using a base binder alloy comprising 66-93% nickel, 7-34% iron, and 0-9% cobalt, with additional elements like W, Mo, Cr, and C, which is sintered with hardness carriers like tungsten carbide to achieve comparable hardness and fracture toughness to cobalt-based hard metals while reducing cobalt content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If Ni-based or FeNi-based binder alloys are used to replace cobalt-based alloys, then occupational health safety is improved and corrosion resistance is enhanced, but hardness and hot hardness decrease making the material unsuitable for machining metallic materials
Solution Approach 1:
The invention changes the compositional parameters of the binder alloy by introducing a specific FeCoNi system with controlled ratios of Fe (30-70 wt%), Co (5-40 wt%), and Ni (5-40 wt%), along with carbide-forming elements. This parameter optimization allows achieving both reduced cobalt content for health safety and sufficient hardness for machining applications.
Solution Approach 2:
The invention creates a composite binder alloy system combining Fe, Co, Ni, and carbide-forming elements (W, Mo, Cr, V, Ta, Nb, Ti, Zr, Hf, Al, Mn, B) that work synergistically. The composite nature allows each element to contribute specific properties: Fe for health safety and corrosion resistance, Co for hardness enhancement, Ni for oxidation resistance, and carbide formers for strengthening the binder matrix.
2Object-affected harmful factors
If FeCoNi-based binder alloys are used, then cobalt content can be reduced for health safety, but fracture toughness (K1C) values decrease making the material less reliable under mechanical stress
Solution Approach 1:
The invention optimizes the Fe:Co:Ni ratio parameters within specific ranges (Fe: 30-70 wt%, Co: 5-40 wt%, Ni: 5-40 wt%) to achieve the right balance between reduced cobalt content and maintained fracture toughness. The presence of carbide-forming elements further modifies the microstructure to enhance toughness.
Solution Approach 2:
The composite FeCoNi binder alloy with carbide-forming elements creates a refined microstructure where carbide precipitates strengthen the binder matrix and improve fracture toughness. The synergistic interaction between multiple elements produces a binder that maintains reliability even with reduced cobalt content.
3Reliability
If Ni-based binder alloys are used to achieve corrosion and oxidation resistance, then chemical resistance is improved, but hardness values are too low for universal hard metal applications
Solution Approach 1:
The invention modifies the binder composition by adding carbide-forming elements (W, Mo, Cr, V, Ta, Nb, Ti, Zr, Hf, Al, Mn, B) to the FeCoNi base alloy. These elements form hard carbide phases within the binder matrix, significantly increasing hardness while preserving the corrosion and oxidation resistance provided by the FeNi-rich composition.
Solution Approach 2:
The invention creates a composite structure where the FeCoNi binder matrix provides corrosion and oxidation resistance, while dispersed carbide phases (formed from W, Mo, Cr, V, Ta, Nb, Ti, Zr, Hf, Al, Mn, B) provide hardness enhancement. This composite approach allows simultaneous achievement of chemical resistance and mechanical strength.
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 resulting hard metals exhibit hardness and fracture toughness comparable to cobalt-based materials, with reduced cobalt content, enhancing occupational health and suitability for high-temperature applications.
Implementation Method 1
Liquid-phase sintering results in formation of a binder alloy based on Ni
Data Source
AI summary
A sintered composite material obtainable by a method which includes providing a composition which includes at least one hardness carrier and a base binder alloy, and sintering the composition. The base binder alloy includes from 66 to 93 wt.-% of nickel, from 7 to 34 wt.-% of iron, from 0 to 9 wt.-% of cobalt, and up to 30 wt.-% of one or more elements selected from W, Mo, Cr, V, Ta, Nb, Ti, Zr, Hf, Re, Ru, Al, Mn, B, N and C. The wt.-% proportions of the base binder alloy add up to 100 wt.-%.