As light as ceramics, but harder than steel

Ceramics are some of the oldest artificial materials in human history. Finds suggest that ceramics, i.e., inorganic non-metallic materials, were used as far back as 25,000 years ago. They include stoneware, terracotta, and porcelain, for example. But ceramics aren’t used only in households and museums but also increasingly in high-tech components as a more capable alternative to steel. The motion technology company Schaeffler, for instance, produces balls for high-precision rolling bearings from ceramics instead of steel for forward-thinking industries such as wind energy, aerospace, and nearly all electrified applications.

Technical ceramics like that are characterized by extreme hardness, minimal mass, resistance against high temperatures and chemicals, high wear resistance, low friction against steel, and excellent electrical properties in terms of insulation and dielectric strength. These characteristics make ceramics a material that’s favored by sectors such as wind and solar power, fuel cells, the chemical industry, electrical engineering, high-temperature engineering, aerospace, mechanical engineering, microsystem engineering, or medical device technology.

The material properties of ceramics are inseparably linked to the manufacturing steps they involve, which consist of preparing the powder, forming, and firing. Due to various firing processes and firing atmospheres as well as the grain size and firing temperatures, a wide variety of properties of the same substance mixture can be achieved.

The evolution of understanding the properties microstructure in the realm of ceramics keeps creating novel material concepts. In addition to fiber composite materials, hybrid composites based on ceramic-metal-polymer combinations are becoming more and more important. Schaeffler Special Machinery recently presented a novel system for multi-material 3D printing that can produce parts in a material combination of metals and ceramics. “The solution provides customers with innovative material combinations, new functional integration in components and tools, plus higher flexibility in the design of products and tools,” says Bernd Wollenick, Senior Vice President Schaeffler Special Machinery.

Indications are that ceramics will become a key element in the development of lighter, safer, and more powerful solid-state traction batteries and so might decisively influence the evolution of electric mobility. In a solid-state battery, a thin ceramic layer works simultaneously as a solid electrolyte and separator. However, up to now, the sintering process to produce the ceramic elements used to require temperatures above 1,000 °C (1,832 °F). That caused technical problems as well as driving up energy consumption and price. But a new synthesis process developed by researchers at the Massachusetts Institute of Technology (MIT) and TU Munich only requires 500 °C (932 °F) and so could become an important door opener for the market entry of ceramic solid-state batteries with ranges of more than 1,000 kilometers (621 miles).