# Optimizing SPS-Processed Pure Tantalum: Effects of Temperature, Pressure, and Time

## TL;DR

This paper studies how to optimize the production of pure tantalum using spark plasma sintering, focusing on temperature, pressure, and time to achieve high density and fine grain structure.

## Contribution

The study systematically optimizes SPS parameters to achieve high-density pure tantalum and identifies the transition in microstructure and fracture behavior.

## Key findings

- A relative density of 98.7% was achieved under 1450 °C, 40 MPa, and 10 min holding time.
- Grain size increases rapidly once relative density exceeds 96%, leading to a shift in fracture mechanism.
- The sintering process of pure Ta involves two stages: densification and grain growth.

## Abstract

Pure tantalum (Ta) is widely used in applications such as capacitors and semiconductor coatings due to its high melting point, excellent corrosion resistance, and good biocompatibility. In this study, spark plasma sintering (SPS) technology has been employed to successfully prepare high-density, fine-grained pure Ta through systematic optimization of sintering temperature, pressure, and holding time. The results indicate that sintering temperature plays a predominant role on the densification behavior. Increasing the sintering pressure and prolonging the holding time also contribute to further enhancing the densification. Under the process conditions of 1450 °C, 40 MPa, and a holding time of 10 min, the relative density of the sample reaches 98.7%. Microstructural analysis reveals that the sintering process of pure Ta can be divided into two main stages: densification-dominated and grain growth-dominated. When the relative density exceeds a threshold value (approximately 96% in this study), the grain size increases rapidly from 4.43 μm to 28.87 μm. This grain coarsening leads to a transition in the fracture mechanism from a mixed mode of intergranular and cleavage fractures to completely intergranular fracture, which significantly reduces the bending strength and plastic deformation capacity of the material.