2134/11535063.v1 Reza Gheisari Reza Gheisari Henry Chamberlain Henry Chamberlain George Chi-Tangyie George Chi-Tangyie Shiyu Zhang Shiyu Zhang Athanasios Goulas Athanasios Goulas Chih-Kuo Lee Chih-Kuo Lee Tom Whittaker Tom Whittaker Dawei Wang Dawei Wang Annapoorani Ketharam Annapoorani Ketharam Avishek Ghosh Avishek Ghosh Vaidhy Vaidhyanathan Vaidhy Vaidhyanathan William Whittow William Whittow Darren Cadman Darren Cadman J. C. Vardaxoglou J. C. Vardaxoglou Ian M Reaney Ian M Reaney Daniel Engstrom Daniel Engstrom Multi-material additive manufacturing of low sintering temperature Bi2Mo2O9 ceramics with Ag floating electrodes by selective laser burnout Loughborough University 2020 Additive manufacturing Metamaterials Multi-material 3D printing Selective laser burnout Co-fired ceramics Mechanical Engineering 2020-01-09 09:46:18 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Multi-material_additive_manufacturing_of_low_sintering_temperature_Bi2Mo2O9_ceramics_with_Ag_floating_electrodes_by_selective_laser_burnout/11535063 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.