Aerospace manufacturers face extreme pressure to lower costs, while increasing performance and satisfying stringent safety standards. Producers in the commercial airline, defense and space exploration sectors continually seek new materials that are reliable and robust, and meet the needs of highly specialized applications.
Role of Advanced Ceramics in Aerospace Industry
Advanced ceramics, such as Alumina, Silicon Nitride and Aluminum Nitride are currently being used to manufacture critical aerospace components, because they have several advantageous physical properties. These inorganic, non-metallic materials retain dimensional stability through a range of high temperatures and exhibit very high mechanical strength. They also demonstrate excellent chemical resistance and stiffness-to-weight ratio, thereby providing manufacturers with the ability to design components that offer optimal performance in their intended application.
This article discusses the growing use of advanced ceramics in the manufacture of aerospace components and the key role that Morgan Advanced Materials is playing in this industry. Morgan Advanced Materials is a leading manufacturer of innovative products made from a range of ceramic, glass, precious metal, piezoelectric and dielectric materials.
Instrumentation and Control Systems
Developments in material science, as well as recently introduced manufacturing techniques, have led to the development of advanced ceramics that serve critical functions in aircraft instrumentation and control systems, missile guidance systems, satellite positioning equipment, ignition systems, fire detection and suppression, instrument displays and engine monitoring equipment.
Advanced Ceramics in Seals and Thermocouples
Advanced ceramics from Morgan Advanced Materials are also ideally suited for aerospace applications that provide a physical interface between different components, due to their ability to withstand the high temperatures, vibration and mechanical shock typically found in aircraft engines and other high stress locations. Ceramics are commonly found in seals for gas turbine engines, fuel line assembly, and thermocouples. Where ceramic/metal assemblies are required, joining the two materials generally involves metallizing the ceramic surface and then brazing the components together.
Advanced Brazing Materials for Aero Engine Component Repair
Research into the development of advanced brazing materials for aero engine component repair has also led to the development of brazing materials ideal for the repair of gas turbine engine components. One example is the use of pre-sintered preforms (PSP) for high temperature braze repair applications. With turbine temperatures reaching up to 1300ºC (2350ºF) and the presence of hot corrosive gases, components experience considerable erosion and wear.
The pre-sintered preforms consist of a blend of superalloy and low melting point braze and are customized to fit the shape of the component and then tack-welded into place and brazed. The ability to provide a range of near net thicknesses can eliminate the need for most post-braze machining and extend the life of engine components by up to 300 percent, making it a more reliable and cost effective method than traditional welding which requires post-braze machining or grinding.
Advanced Ceramics for Ion Propulsion Systems
Advanced ceramics are playing a critical role in the development of highly-efficient and cost-effective new technologies for space travel. Morgan Advanced Materials division in Erlangen, Germany has been working with a European space development program for a number of years to support its research of ion propulsion systems. A lightweight alternative to traditional chemical propulsion, ion engines have the potential to push spacecraft up to ten times faster with the same fuel consumption, thereby significantly decreasing vehicle size and increasing travel distance.
Ion propulsion technology, which uses electricity to charge heavy gas atoms that accelerate from the spacecraft at high velocity and push it forwards, traditionally incorporated quartz discharge vessels. Quartz has now been replaced by Alumina because of the need for a material with the same dielectric properties but with higher structural stability. Alumina is easier to fabricate and offers good thermal shock resistance, ensuring that the chamber can withstand the extremes of temperature that occur during plasma ignition. It is also lighter, which reduces the costs associated with each launch.
Driven by the aerospace industry’s demand for higher performance and lower costs, material scientists and ceramics component manufacturers will continue to develop new materials and processes that take advantage of the powerful physical, thermal and electrical properties of advanced ceramic materials.