Mar 27, 2019
Ceramics have held an important place in the manufacturing strategies of automotive companies from the very earliest days of mass production, perhaps the most obvious component being the spark-plug porcelain insulator. The wide range of technical ceramics available today offers enormous scope to auto designers and innovators when improving vehicle operation, performance, weight, fuel efficiency, environmental impact, and driver comfort and safety. Each with their own very special contribution to make, we see variously the incorporation of materials such as alumina, zirconia, yttria stabilized zirconia, silicon carbide, silicon nitride, aluminum nitride, boron nitride, ceramic matrix composites (CMCs), silicates, and cermets (such as aluminum-boron-carbide).
The reliance on technical ceramics is evidenced by the very many representatives from the world’s leading auto manufacturers who motor over to Cleveland each year for Ceramics Expo, not least drawn by the extraordinary combination of properties that this family of materials provides. These characteristics vary, but can include electrical and thermal insulation; excellent resistance to extreme heat, wear, corrosion, UV, thermal shock and chemicals; high thermal conductivity; mechanical strength; low weight; and electromagnetic compatibility. In many cases, this is allied with cost competitiveness.
In 2018, despite some difficult trading conditions, total US auto sales increased slightly to reach 17.3 million units. The fact that sales rose at all seems to be solely on the back of electric vehicle take-up – conventional vehicle sales dropped marginally while sales of EVs rose 75% over the 2017 figure.
Globally positioned innovator, and once again an exhibitor at Ceramics Expo, CeramTec has many years’ experience in this sector, which is enabling the company to actively contribute to the forward propulsion of the e-mobility industry, for example with advanced ceramic components for use in drive concepts such as fuel cells, and systems for generating, transmitting, storing and distributing energy, as well as in power electronics and temperature management.
As the company emphasizes, “It is especially areas in which traditional materials such as metals and plastics reach their limits where advanced ceramics really prove their strengths. They are distinguished by their mechanical strength and tribological properties, as well as electrical insulation and excellent thermal conductivity. They are resistant to temperature change, chemicals and corrosion.” On the basis of the wide range of materials and the resulting combinations of properties, CeramTec offers customized solutions for the most varied demands of e-mobility, which range across the entire spectrum of the e-mobility sector, including automobiles, electric bikes, electric motorbikes and other mobility solutions on land, water and air.
Versatility in application is equally influential in material choice. Good examples are tiny ceramic components from CeramTec that are already firmly rooted in the automotive industry, largely unseen but making a valuable contribution. “Piezoceramic parts generate an electrical charge when mechanically deformed,” explains the company, “while conversely, they are also capable of converting electrical signals into mechanical movement or vibration. As a result, they are predestined for sensor and actuator applications, in power transducers or in intelligent engine management systems, among others. They also play an important role in safety applications such as distance sensors, parking aids and airbags.”
We should remember that the role played by ceramics is not confined to solid components, but also includes highly effective coatings (such as thermal barrier), laminates, pastes and glass enamels used across the automotive spectrum. Exhibitor Johnson Matthey has been pushing the technical boundaries in the latter category. “The expectations of our products are ever increasing in our industry, and our glass materials are formulated to meet a number of physical and chemical properties sometimes conflicting with each other,” comments JM. “Our most recent technology example, for an obscuration product in automotive laminating glass, is required to surpass current minimum durability standards over a wide firing range, but also offer the low toughening temperatures expected in the industry – a sophisticated balancing act pulled off by careful attention to the glass composition.”
The company notes that glass fluxes also play a major role in its portfolio of silver paste products. The additional dimension of electrical conductivity is factored into the design of the glasses used. Automotive requirements are placing greater emphasis on durability and non-leaded soldering. Electronic pastes, for example in capacitor applications, require frit-based formulations with good firing stability and improved substrate adherence.
Looking ahead, quite literally for much of the time, the industry is also addressing all the novel technologies required to realize the potential of autonomous cars. “When we think of glass in cars, we think of the obvious: windshields and windows,” says our exhibitor Schott. “But driverless cars will contain more glass, and more glass-ceramics, than one might think.”
In particular, explains the company, the lidar systems used to identify objects in the road and guide the vehicle will require glass and glass-ceramic for critical components: the protective entrance window, the beam splitter and the narrow bandpass filters. “But these components will also have to be unusually robust,” adds Schott. “The protective window must be strong enough to withstand abrasive road dust and the impacts of small rocks. And the entire system must work 100% of the time, during daylight or night-time, in freezing temperatures and tropical humidity. Schott BOROFLOAT 33 has the unique combination of properties to work as any component in a lidar system.”
With that mention of surrounding temperature, we return to another element of the CeramTec portfolio for the automotive sector, addressing the high level of thermal control necessary in tomorrow’s powertrains. “Just how versatile CeramTec advanced ceramics can be in e-mobility applications is evidenced in an impressive way by CeramCool,” comments the company. “Drives in electric vehicles must be capable of delivering the highest-possible electrical power. The challenge here lies in controlling this power in the smallest of spaces – constantly and reliably over long periods of time.”
The surrounding temperature plays an important role. It is here that the highly efficient CeramCool air or fluid heat sinks come into play as they present extremely low thermal resistance during cooling, while at the same time providing electrical insulation. This also makes CeramCool suitable for use in thermal management for batteries, in voltage converters, and in drive control systems or braking energy recovery.
Learn more about ceramic applications for the automotive industry at Ceramics Expo 2019.