Cooling Source Strategy for Highly Porous Tungsten Using Freeze-Drying Technology

Porous tungsten is composed of tungsten skeleton with numerous internal pores, and shows high temperature resistance, good corrosion resistance, large specific surface and high permeability, promising for aviation, electronics, and high temperature manufacture applications. Formation of high porosity of tungsten structures has been a key issue to expand its application. In this study, porous tungsten was prepared using a freeze-drying method, and influences of different cooling sources’ distributions on microstructures and properties of porous tungsten were investigated. Results showed that the distribution of cold source has a great influence on detailed structures of porous tungsten. Porous tungsten prepared using a cooling source along the axial direction has the highest porosity of 80%, with a lamellar structure along both vertically and freezing direction, and it shows a compressive strength of 0.99 MPa.