CerAMfacturing: electrically conductive and insulating Si₃N₄-SiC-MoSi₂ multi-material parts

Additive manufacturing (AM) of functional components

In order to meet the ever-increasing demands for the functionalization and miniaturization of components, it is necessary to combine differ­ent materials in components with highly complex geometries. Property combinations such as dense/porous or electrically or thermal­ly conductive and insulating in additively manufactured components enable the produc­tion of parts with previously unattained prop­erties. AM technologies based on thermoplastic binder systems, in which the materials are applied only at the points at which they are needed, are particularly suitable for the pro­duction of multi-material components. These AM technologies also offer the chance to pro­cess an almost unlimited materials portfolio.

Electrically conductive and insulating properties in one component

Electrically conductive silicon nitride is a high-temperature-stable mixed ceramic. It consists of silicon nitride (Si₃N₄), an oxide grain bound­ary phase and one or more electrically conduc­tive components. These can be TiN, SiC and various metal silicides. Because of the special nature of the material structure, even minor changes in composition are enough to make a material conductive or non-conductive. The combination of Si₃N₄-SiC-MoSi₂ makes it possi­ble to realize complex ceramic sensors, heaters, and igniters, within one manufacturing step, which can be used at temperatures above 1000 °C (Figures 1–3). At Fraunhofer IKTS, various AM technologies are available for this.

Process diversity at Fraunhofer IKTS

Multi Material Jetting (CerAM MMJ) is a drop­let-based AM technology developed at IKTS that enables the manufacturing of components from one or more materials simultaneously by fusing individual thermoplastic droplets. Highly particle-filled thermoplastic feedstocks are deposited in the molten state. The technol­ogy is currently being commercialized in the form of an Fraunhofer IKTS spin-off within the framework of an Exist research grant project (03EFQSN180) of the BMWK. Starting 2023, the spin-off – AMAREA Technology GmbH – will enter the market as system provider for MMJ 3D printers and associated printing materials and services.

Fused Filament Fabrication (CerAM FFF) relies online-based material application. The material is fed in the form of continuous filaments (developed at IKTS) with a wide variety of sin­tered materials used for particle filling. The existing system technology has a dual print head and thus also offers the possibility of manufacturing multi-functional components.

Services offered

• Component development (design and sha­ping based on different AM technologies and materials
• Customized filament development and dis­tribution for CerAM FFF