First ball milling mixed powder, cold pressing, vacuum hot pressing sintering of copper nickel aluminum, copper nickel chromium alloy surface why not mirror, the same process of sintering copper nickel silicon alloy surface mirror. Is it the problem of sintering process or what is the reason ? Do you have a boss to help answer.
The difference in surface appearance after sintering between copper-nickel-aluminum (Cu-Ni-Al) and copper-nickel-chromium (Cu-Ni-Cr) alloys, as well as copper-nickel-silicon (Cu-Ni-Si) alloys, can indeed be attributed to various factors related to the sintering process and alloy composition.
ALLOY COMPOSITION
- Cu-Ni-Al Alloy: The presence of aluminum in the Cu-Ni-Al alloy may lead to the forming of an oxide layer on the surface during sintering. Aluminum readily oxidizes, resulting in a non-mirror-like appearance.
- Cu-Ni-Cr Alloy: Chromium (Cr) is known for its oxidation resistance. The Cu-Ni-Cr alloy may exhibit better surface properties due to the protective chromium oxide layer formed during sintering.
- Cu-Ni-Si Alloy: Silicon (Si) does not readily form a thick oxide layer during sintering. Hence, the Cu-Ni-Si alloy surface may remain relatively mirror-like.
- OXIDATION AND SURFACE CHEMISTRY
- Cu-Ni-Al Alloy: Aluminum tends to oxidize at elevated temperatures, forming a thin oxide layer on the surface. This layer can scatter light and reduce reflectivity, resulting in a non-mirror appearance.
- Cu-Ni-Cr Alloy: Chromium forms a stable oxide layer (chromium oxide) that protects the surface from further oxidation and contributes to its mirror-like appearance.
- Cu-Ni-Si Alloy: Silicon does not readily form a thick oxide layer, allowing the surface to maintain its reflective properties.
- MICROSTRUCTURE AND GRAIN GROWTH
- Cu-Ni-Al Alloy: The microstructure and grain growth during sintering play a role. If the grain boundaries are irregular or the grain size is large, it can affect surface smoothness.
- Cu-Ni-Cr Alloy: Proper sintering conditions can lead to finer grain structures and a smoother surface.
- Cu-Ni-Si Alloy: Similar considerations apply to the Cu-Ni-Si alloy.
- SINTERING PARAMETERS
- Temperature: Sintering temperature affects grain growth, densification, and surface quality. Optimal temperature control is crucial.
- Pressure: Pressure during sintering influences densification and microstructure. Higher pressure may lead to smoother surfaces.
- Heating Rate and Dwell Time: These parameters impact the sintering process and surface quality.
- SUFRACE FINISHING BEFORE SETTINGS
- The initial surface finish (before sintering) can also affect the final appearance—pre-sintering surface preparation matters.
- OXIDATIN PREVENTION TECNIQUES
- To achieve mirror-like surfaces, consider using protective atmospheres (e.g., reducing or inert gases) during sintering to minimize oxidation.
Source(s)
1. A critical review on spark plasma sintering of copper and its alloys ...
2. Engineers Guide to Sintering - f.hubspotusercontent20.net
3. High-Temperature Oxidation of the Copper–Nickel Alloys Synthesized by ...
4. Sintering Process | Aluminum Sintering | BTU International
5. Features of Oxidation of Copper–Nickel Alloys Synthesized ... - Springer
6. Mechanical and Physical Properties of Differently Alloyed Sintered ...
7. Bonding Strength of Cu Sinter Die-Bonding Paste on Ni, Cu, Ag, and Au ...
8. Sintered Fe-Mo-Cu-Ni-Si-C Composites Produced by SiC, Nickel ... - Springer
9. https://doi.org/
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