Tech Team · Kintek Solution

The final stage of sintering is a critical phase where the material transitions into a nearly fully dense and solid structure. At this stage, the majority of the pores and voids have been eliminated, and the material achieves high density, often exceeding 99%. Grain growth becomes significant, and pores may coalesce, leading to an increase in pore size even as density continues to rise. In permanent liquid phase sintering, additional liquid and binder additives flow into any remaining open pores or cracks, ensuring complete bonding and consolidation of the material. This stage is characterized by the dominance of lattice diffusion, which facilitates the final densification and strengthening of the sintered product.

Key Points Explained:

1. High Density and Solidification:

   • In the final stage of sintering, the material reaches a high density, often exceeding 99% of its theoretical density.
   • The original powder particles have mostly transformed into a solid form, with minimal porosity remaining.

2. Grain Growth and Pore Coalescence:

   • Rapid grain growth occurs during this stage, which can lead to the coalescence of pores.
   • Pore size may increase as pores merge, even though the overall density of the material continues to rise.

3. Lattice Diffusion Dominance:

   • At very high densities, lattice diffusion becomes the dominant mechanism for material transport.
   • This process helps in the final densification and elimination of any remaining microscopic pores.

4. Role of Liquid and Binder Additives:

   • In permanent liquid phase sintering, additional liquid and binder additives flow into any remaining open pores or cracks.
   • These additives help in binding the material together, ensuring a cohesive and strong final product.

5. Completion of Consolidation:

   • The final stage marks the completion of the consolidation process, where the material achieves its desired mechanical properties.
   • The sintered product is now a rigid and cohesive structure, ready for any subsequent processing or use.

6. Cooling and Solidification:

   • After the final stage of sintering, the material is cooled to solidify into its final form.
   • This cooling process ensures that the material retains its structural integrity and desired properties.

By understanding these key points, one can appreciate the complexity and importance of the final stage of sintering in achieving a high-quality, dense, and strong material. This stage is crucial for ensuring that the sintered product meets the required specifications for its intended application.

Summary Table:

Key Aspect	Description
High Density	Material exceeds 99% density, minimal porosity remains.
Grain Growth	Rapid grain growth leads to pore coalescence and increased pore size.
Lattice Diffusion	Dominates material transport, aiding final densification and pore elimination.
Liquid and Binder Additives	Flow into remaining pores, ensuring complete bonding and consolidation.
Consolidation Completion	Material achieves desired mechanical properties, ready for use or processing.
Cooling and Solidification	Ensures structural integrity and retention of desired properties.

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