Fabrication of tubular electrolytes for solid oxide fuel cells using strontium- and magnesium-doped LaGaO3 materials

Long, straight, dense, and even-shaped tubular electrolytes (200-300 mm in length, 2.4-2.5 mm inside diameter and 0.3-0.4 mm wall thickness) were successfully fabricated from strontium- and magnesium-doped ZaGaO(3) materials by way of extrusion. An economic and practical process was developed to extrude the small tubes using water-based and organic-based additives and optimized process parameters. Particle size distribution and specific surface area of the synthesized powder were modified by calcination and ball milling. Obtaining workable pastes played an important role in achieving smooth, linear, even and dense green tubes. The final products showed a dense microstructure and improved mechanical strength over pressing routes. Modulus of rupture of the extruded materials was found to be 180 +/- 16 MPa at room temperature and 113 +/- 11 MPa at 800 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.