Pre-alloyed powders composed of iron,
Copper, nickel, and tungsten serve as the technological foundation for achieving high-performance alternatives to cobalt. They address the inherent drawbacks of mixed elemental powders in the following ways:
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1. Extreme compositional homogeneity Every powder particle contains Fe, Cu, Ni, and W in a constant proportion. This eliminates composition segregation and uneven liquid phase formation caused by differences in density and melting point during sintering, ensuring a consistent microenvironment around each diamond grain.
2. Higher sintering reactivity
Atoms in pre-alloyed powders are pre-bonded, resulting in shorter diffusion paths during sintering. This enables high densification (e.g., the high flexural strength in your data) at lower temperatures (such as the 800–850°C you provided) and within shorter timeframes. This overcomes the challenge of poor sinterability and low densification faced by elemental iron and
Tungsten Powders.
3. Predictable and stable performance Batch-to-batch consistency is far superior to that of mechanically mixed powders—this forms the basis for reliable performance data (85–95% sharpness and 70–90% service life).
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- Mechanism: Dual action of "Cu-Ni liquid phase wetting + W-induced interfacial carbide reaction".
- Implementation: Nickel enhances the wettability and spreading of the Cu liquid phase on diamond surfaces. More critically, tungsten forms a robust carbide layer at the interface, effectively "riveting" diamond grains into the matrix. This bonding force can even surpass the primarily physically adsorbed bonding of pure cobalt.
- Mechanism: Synergy of "Fe-Ni solid solution strengthening + fine-grain strengthening".
- Implementation: Nickel dissolves in iron to strengthen the iron-based matrix. The homogeneity of pre-alloyed powders and low-temperature rapid sintering inhibit grain growth, forming a fine-grained structure. This allows the material to achieve high hardness (105–110 HRB) while maintaining high flexural strength (1250–1500 MPa) and moderate deflection (1.2–1.5 mm).
- Mechanism: Rational matching between "Fe-W wear-resistant skeleton and Cu-Ni binder phase".
- Implementation: By adjusting the ratio of Fe/W (providing wear-resistant hard phases) to Cu/Ni (providing bonding and self-sharpening properties), the wear rate of the matrix can be precisely controlled. This ensures that new diamond cutting edges are exposed in a timely manner during wear, achieving sharpness comparable to cobalt-based matrices (85–95%).
The ultra-fine Fe-Cu-Ni-W pre-alloyed powder developed by Shijia Micro-tech enables cobalt substitution in the diamond tool industry. This is not a simple replacement of cobalt in traditional matrix powders; instead, it involves targeted formulation optimization to replicate and match the performance of conventional cobalt-based matrix powders.
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Email: sales@sagwell.com
