Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout
journal contributionposted on 09.01.2020, 09:46 by Reza Gheisari, Henry Chamberlain, George Chi-Tangyie, Shiyu Zhang, Athanasios Goulas, Chih-Kuo Lee, Tom Whittaker, Dawei Wang, Annapoorani Ketharam, Avishek Ghosh, Vaidhy Vaidhyanathan, William Whittow, Darren Cadman, J. C. Vardaxoglou, Ian M Reaney, Daniel Engstrom
Additive manufacturing (AM) of co-fired low temperature ceramics offers a unique route for fabrication of novel 3D radio frequency (RF) and microwave communication components, embedded electronics and sensors. This paper describes the first-ever direct 3D printing of low temperature co-fired ceramics/floating electrode 3D structures. Slurry-based AM and selective laser burnout (SLB) were used to fabricate bulk dielectric, Bi2Mo2O9 (BMO, sintering temperature = 620–650°C, εr = 38) with silver (Ag) internal floating electrodes. A printable BMO slurry was developed and the SLB optimised to improve edge definition and burn out the binder without damaging the ceramic. The SLB increased the green strength needed for shape retention, produced crack-free parts and prevented Ag leaching into the ceramic during co-firing. The green parts were sintered after SLB in a conventional furnace at 645°C for 4 h and achieved 94.5% density, compressive strength of 4097 MPa, a relative permittivity (εr) of 33.8 and a loss tangent (tan δ) of 0.0004 (8 GHz) for BMO. The feasibility of using SLB followed by a post-printing sintering step to create BMO/Ag 3D structures was thus demonstrated.
UK’s Engineering and Physical Science Research Council through the grant “Synthesizing 3D metamaterials for RF, microwave and terahertz applications”, SYMETA, grant reference EP/N010493/1
- Mechanical, Electrical and Manufacturing Engineering
- Aeronautical, Automotive, Chemical and Materials Engineering