We recently caught up with Holly Shulman, founder of advanced ceramics developer Ceralink. The company recently developed a method for producing silicon carbide/silicon carbide composites using powder bed inkjet 3D printers from ExOne (see the report “Building the Future: Assessing 3D Printing’s Opportunities and Challenges” — client registration required) as part of a Phase II Small Business Innovation Research (SBIR) grant from the U.S. National Science Foundation (NSF). During the process, a 3D printer deposits a layer of carbon powder, then uses an inkjet printer to deposit an organic binder pre-mixed with additional powder. This method produces a carbon preform which Ceralink converts to silicon carbide by burning away the binder and adding liquid silicon under high pressure – a process known as reaction bonding. The resulting material consists of silicon carbide fibers embedded in a fully dense silicon carbide matrix. Holly said that the material offers lighter weight, higher temperature performance, and higher wear resistance than nickel alloys and titanium alloys for aerospace jet engine components.
Jet engines contain numerous high-value components with complex shapes designed to reduce weight, three factors that favor 3D printing production methods. Using 3D printing methods, additional shape complexity adds no additional cost (as the printer can add material equally well to produce any shape), and reduced weight results in faster production times (as 3D printers throughput outputs material at a fixed rate), not more machining. As aerospace continues to demand lighter weight and higher performance, process development must continue in tandem with materials development. The ability to 3D print an increasingly wide range of materials to achieve required properties will continually test the limits of both the available equipment and process innovation. By incorporating chemical modification post-processing steps into the production process, Ceralink is expanding the range of printable materials using existing printers and materials powders. While bringing Ceralink’s materials to market will involve extensive additional testing and qualification, its development strategy will likely prove a useful tool to 3D printer manufacturers, materials developers, and end users looking to raise the industrial utility of additive manufacturing technologies.