ABSTRACT

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, ε_r = 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 (ε_r) 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.

摘要

共烧低温陶瓷的增材制造（AM）为新型3D射频（RF）和微波通信组件，嵌入式电子产品和传感器的制造提供了一条独特的途径。本文介绍了低温共烧陶瓷/浮动电极3D结构的首次直接3D打印。基于浆料-AM和选择性激光烧断（SLB）被用来制造散装电介质，铋₂沫₂ ö ₉（BMO，烧结温度= 620-650℃，ε _{- [R} = 38），内部带有银（Ag）浮动电极。开发了可印刷的BMO浆料，并对SLB进行了优化，以改善边缘清晰度并烧尽粘合剂而不会损坏陶瓷。SLB提高了保持形状所需的生坯强度，生产了无裂纹的零件，并防止了Ag在共烧过程中浸入陶瓷中。绿色部位是在传统的炉SLB后烧结在645℃下4小时，达到94.5％的密度，4097兆帕，相对介电常数（抗压强度ε _{- [R} 33.8）和0.0004的损耗角正切（黄褐色δ）（ 8 GHz）用于BMO。因此，证明了使用SLB进行印刷后烧结步骤来创建BMO / Ag 3D结构的可行性。