Development of a Diamond Composite in the NI-CO-FE3P-SN-WC System Via Free Sintering for Use in Multi-Find Diamond Pearls
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-11-08 |
| Journal | Revista de GestĂŁo Social e Ambiental |
| Authors | Mateus Valentim Simmer Sopeletto, Alexandre Vianna Bahiense, Victor Moza Ponciano, Carlos Eduardo Gomes Ribeiro, Gustavo de Castro Xavier |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research successfully developed and characterized a novel diamond composite matrix (Ni-Co-Fe3P-Sn-WC) for multi-wire diamond pearls using Powder Metallurgy (PM) and Free Sintering, focusing on reducing cobalt dependence.
- Value Proposition: The NICOFE alloy offers significant environmental and economic advantages by partially substituting expensive and environmentally concerning cobalt (Co) with nickel (Ni).
- Mechanical Performance: The sintered NICOFE pearls achieved comparable compressive resistance (0.95 to 1.12 GPa in the elastic zone) to established commercial alloys (ranging from 0.75 to 1.20 GPa).
- Processing Route: Pearls were manufactured via cold uniaxial compaction followed by Free Sintering in a controlled reducing atmosphere (70% H2 / 30% N2) at a peak temperature of 960 °C.
- Critical Deficiency: Microstructural analysis (MEV) identified point deficiencies, specifically high porosity and poor adhesion (âpull-outâ phenomenon) in the transition zone between the diamond crystal and the NICOFE matrix, indicating a weak bond.
- Strategic Implication: The study supports the development and nationalization of diamond tool technology for the Brazilian ornamental stone industry, promoting a more accessible supply chain.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Matrix Composition (Ni) | 50 | % mass | Partial Cobalt substitute |
| Matrix Composition (Co) | 25 | % mass | Remaining Cobalt content |
| Matrix Composition (Fe3P) | 18 | % mass | Iron Phosphorus content |
| Matrix Composition (Sn) | 3.5 | % mass | Tin content |
| Matrix Composition (WC) | 3.5 | % mass | Tungsten Carbide content |
| Compaction Aid | 0.1 | % mass | Magnesium Stearate [Mg(C18H35O2)2] |
| Diamond Concentration | 0.35 | g/cm3 | FEPA standard concentration |
| Theoretical Composite Density | 8.17 | g/cm3 | Calculated density of final alloy |
| Real Density (Green Pressed) | 5.1 | g/cm3 | Density before sintering |
| Green Pressed Mass | 1.18 | g | Mass of compacted pearl |
| External Pearl Diameter (ĂExt) | 7.3 | mm | Standard multiwire pearl dimension |
| Internal Pearl Diameter (ĂInt) | 5.0 | mm | Standard multiwire pearl dimension |
| NICOFE Compressive Strength | 0.95 to 1.12 | GPa | Elastic zone limit stress |
| Commercial A Compressive Strength | 1.00 to 1.20 | GPa | Elastic zone limit stress |
| Commercial B Compressive Strength | 0.75 to 1.07 | GPa | Elastic zone limit stress |
Key Methodologies
Section titled âKey MethodologiesâThe diamond composite pearls were manufactured using Powder Metallurgy techniques, followed by mechanical and microstructural characterization.
- Material Selection and Preparation:
- Metallic powders (Ni, Co, Fe3P, Sn, WC) and HWD 92 Ti monocrystalline diamonds (Ti coated) were selected.
- Three diamond granulometries (35/40, 40/50, 50/60) were used, totaling 4,700 particles/carat.
- Mixing and Granulation:
- Elemental powders were mixed with diamond crystals for 180 minutes (Dr. Fritsch MP - 10 mixer) to ensure homogenization.
- The mixture was granulated (Dr. Fritsch GA 300 granulator) to agglomerate fine particles (< 44 ”m), preventing flow obstruction during pressing.
- Compaction (Pressing):
- Cold uniaxial compaction was performed using an automatic hydraulic press (Dr. Fritsch BPC 100).
- A four-part matrix (double compaction action) was used to shape the green pressed pearls, controlling mass and density (target real density: 5.1 g/cm3).
- Sintering (Free Sintering):
- Sintering was carried out in a continuous conveyor belt furnace (Bertoncello GBF 180) with a controlled reducing atmosphere (70% H2 / 30% N2).
- Temperature Profile: Zone I (480 °C), Zone II (780 °C), Zone III (960 °C).
- Speed: 60 mm/minute.
- The N2 component promoted surface nitriding, enhancing hardness and wear resistance.
- Characterization and Testing:
- Mechanical Testing: Uniaxial compressive strength tests were performed (EMIC DL 100KN universal testing machine) at 1 mm/minute to determine the maximum compressive strength of the metallic matrices.
- Microstructural Analysis: Scanning Electronic Microscopy (MEV, HITACHI TN 3030 Plus) coupled with Dispersive Energy Spectroscopy (EDS) was used to analyze phase identification, chemical composition, and the transition zone integrity.
Commercial Applications
Section titled âCommercial ApplicationsâThe technology developed is directly relevant to the abrasive tool manufacturing sector, particularly within the ornamental stone processing industry.
- Ornamental Stone Processing: Primary application is the production of diamond pearls for multi-wire saws, used for cutting large blocks of granite, marble, and other rocks into slabs.
- Abrasive Tool Manufacturing: Provides a viable, high-performance alternative matrix alloy for various diamond tools (blades, wheels, disks) where cobalt reduction is desired.
- Strategic Material Substitution: The successful partial replacement of cobalt (Co) with nickel (Ni) addresses supply chain volatility and high material costs, offering a more accessible and sustainable material base for diamond tool binders.
- National Technology Development: Supports the nationalization of advanced diamond tool manufacturing technology, reducing reliance on imported materials and expertise within the local stone industry.
View Original Abstract
Objective: The main objective of this study is to manufacture a diamond composite with a metallic matrix based on Ni-Co-Fe3P-Sn-WC, using the Free Sintering process through cold uniaxial compaction, intended for the production of pearls for diamond wire saws, used in cutting ornamental stones. Theoretical Framework: The multi-wire technology represents an advancement in cutting ornamental stone blocks, allowing the simultaneous production of multiple slabs. Powder metallurgy is the predominant technique used in the manufacturing of pearls for diamond wire saws. Through testing, including scanning electron microscopy (SEM) and shear tests, it is possible to evaluate the alloyâs strength, diamond crystal adhesion, and failure behavior of the alloy. Methodology: The adopted methodology involves the processing and characterization of pearls for diamond wire saws, following the techniques of powder metallurgy. Initially, parametric calculations were performed using Excel, providing a basis for subsequent analyses. Diamond-coated pearls were produced with different proportions of constituent elements, and uniaxial compressive strength tests and microstructural characterization were conducted to evaluate the results. Results and Discussion: In the adhesion tests to the metal tube, the pearls produced with the NICOFE alloy showed similar performance to the commercial pearls âAâ and âB,â with satisfactory direct shear strength values. However, some point defects were observed, such as porosity in the transition zone, creating a weaker bond, negatively impacting the final strength of the composite. Analysis of the commercial samples indicated that diamond abrasion was not related to the composition of the sintered alloy. Research Implications: This research suggests significant economic and technological implications, such as the development and nationalization of technology for the ornamental stone industry. The use of the NICOFE alloy could strengthen the local industry by providing a viable and more accessible alternative for the production of diamond pearls. Originality/Value: The NICOFE blend presents technical advantages for manufacturing diamond wire pearls, highlighting the environmental benefits from reduced cobalt use and economic advantages by offering more accessible materials for the ornamental stone industry.