Cemented Carbide Sinterability via Sponge Binder
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Solution Overview
Problem
Cemented carbides with fine WC grain size and low binder phase content face challenges in achieving optimal sinterability and homogeneity, leading to porosity issues that affect wear resistance, which are difficult to address with existing powders having broad particle size distributions and agglomerated structures.
Innovation Solution
The use of binder phase powders with specific surface areas of 3 to 8 m^2/g and grain sizes between 1 and 5 µm, particularly with a sponge shape, improves sinterability and homogeneity, reducing nanoporosity and enhancing wear resistance by ensuring better dispersion and distribution of the binder phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fine WC grain size and low binder phase content are used, then hardness is improved, but sinterability deteriorates and porosity increases
Solution Approach 1:
The patent changes the particle morphology parameter of the binder phase from conventional spherical/agglomerated shapes to sponge-shaped particles. This morphological parameter change increases the specific surface area of the binder phase, improving its ability to wet and bond fine WC grains at low binder content, thereby maintaining sinterability while achieving fine grain size and high hardness
Solution Approach 2:
The invention utilizes sponge-shaped binder phase particles that inherently possess a porous internal structure. This porous morphology provides high surface area-to-volume ratio, enabling effective wetting of WC particles with reduced binder phase content, thus resolving the contradiction between low binder content (for hardness) and sufficient binder distribution (for sinterability)
2Strength
If fine WC grain size and low binder phase content are used, then wear resistance is improved, but microstructural homogeneity deteriorates due to binder phase lakes
Solution Approach 1:
The patent modifies the morphological parameter of the binder phase to sponge-shaped particles with increased specific surface area. This change ensures uniform distribution and wetting of fine WC grains, preventing binder phase lakes and achieving homogeneous microstructure even at low binder content, thereby maintaining both wear resistance and microstructural homogeneity
3Ease of manufacture
If conventional binder phase powders with broad particle size distribution are used, then ease of manufacture is improved, but microstructural homogeneity deteriorates
Solution Approach 1:
The patent narrows and optimizes the particle size distribution parameter of the binder phase while introducing sponge-shaped morphology. This controlled particle size distribution combined with high surface area morphology enables homogeneous dispersion and wetting of WC particles, achieving microstructural homogeneity while maintaining manufacturability through standard powder metallurgy 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 approach results in a cemented carbide with improved sinterability and reduced nanoporosity, maintaining microstructural homogeneity and wear resistance even after heat treatment, demonstrating enhanced performance in applications like woodworking, drilling, and metal cutting.
Implementation Method 1
at least part of the binder phase powder has a specific surface area of 3 to 8 m 2[0010]
Implementation Method 2
The use of binder phase powders with specific surface areas of 3 to 8 m^2/g and grain sizes between 1 and 5 µm, particularly with a sponge shape, improves sinterability and homogeneity, reducing nanoporosity and enhancing wear resistance by ensuring better dispersion and distribution of the binder phase
Implementation Method 3
by powder metallurgical methods milling, pressing and sintering of powders
Data Source
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AI summary
The present invention relates to a cemented carbide with a homogeneous and dense microstructure of hard constituents in a well distributed binder phase based on Co and/or Ni with a porosity of A00-B00according to ISO 4505. The cemented carbide has a nanoporosity of less than 2.5 pores/1000 µm2 with a size of 0.5-1 µm. The cemented carbide is produced by using a binder phase powder with a specific surface area of 3 to 8 m2/g with a sponge shape and a grain size of the sponge shaped particles of between 1 and 5 µm.