The aerospace industry leaves no margin for error, demanding materials that can withstand high altitudes, high speeds, and extreme temperatures upwards of 1,000 degrees to meet the strict safety requirements of the industry.
As engineers develop designs that push the boundaries of what’s possible, they search for new materials, or adaptations of materials, that can withstand increasingly extreme environments. Many new designs need materials that can endure extreme temperatures for long stretches of time, like seals and bearings that go into ovens, rockets, and turbines that can see temperatures above 1000°F. These temperatures wreak havoc on most traditional materials, rendering them expensive to replace or dangerous to operate.
Manufacturers have struggled with proper sealing of low viscosity fluids for years. Effectively stopping materials like Freon refrigerants, liquid oxygen, propane, and acetone are vital to production for industry leaders. Luckily, there's now a solution to this (un)impenetrable problem: antimony-impregnated carbon graphite.
2020 marks 75 years since Metallized Carbon Corporation was founded. Read more and watch the video from our team.
New materials these days can perform under an incredible amount of stress, and many of them perform vital roles in the daily grind of our communities and businesses. The quality of materials has had to improve to keep up with the increasingly complex environments that materials are put through. One of the most taxing elements that would tear down traditional materials is heat. These days, modern mechanical parts perform incredible feats everywhere from rocket ships to ovens. Here are some applications where new high-performance parts have replaced traditional materials, so that when they find themselves in hot water, they’re actually quite at home:
Refineries and power plants house hundreds of valves that control the flow of oil, water, steam and other liquids. There are certain critical valves that must be counted on to operate in the case of a catastrophic failure, including a fire in the system. High temperature resistant valve seats made of specialized carbon graphite can operate and maintain their seal for hours at temperatures over 1000F where Teflon and other valve seat materials will melt and fail. Continuous evaluation of materials used in industries that deal with volatile substances in high-temperature and high-stress environments are necessary in reducing catastrophic material and system failures.
Many systems on airplanes are driven by high pressure air that is bled off the main engines. This high-pressure air is very hot, often over 900F. The air flow is controlled by high temperature valves which should use low friction, non-galling bearing surfaces to minimize the torque required to open and close the valve and specialized materials for the stem bearings and radial seals.
All plywood, gypsum board, ceiling tile, veneer boards and other similar products must go through a drying process after they are formed. This process is performed in long, continuous, multilevel ovens at temperatures up to 1,100F. The boards are loaded onto decks that have rollers positioned every 12” to support them during the drying process. These rollers are supported on either side by customized carbon graphite bearings that provide sufficient lubrication and long life in high temperature steam environments. The bearings are installed into quick change hardware that can be easily replaced during routine maintenance.
Spacecraft propulsion engines require the movement and sealing of extremely high temperature gasses during take-off. The primary sealing materials in these engines operate at over 1000F. Customized graphite parts have the ability to provide a seal for the entirety of the take-off burn to deliver astronauts safely to complete their mission.
In the food industry, materials must be FDA-approved as GRAS and able to be used in continuously rotating baking ovens for bread, pizza, chips and other foods. These ovens typically operate over 400F and more importantly cannot have oil or grease drip onto the food, so self-lubricating materials, such as special impregnated carbon graphite alloys, that can withstand both high temperatures and continuous movement over long periods of time are key here.
Dampers are used to control the flow of hot air into utility boilers. This air can be as hot as 900F, which can cause bearings lubricated with oil and grease to seize, resulting in lower efficiencies and unplanned shutdowns. Self-lubricating bearings that perform in high temperatures allow the dampers to efficiently modulate the hot air flow into power plant boilers. Regulation of power plant equipment and ensuring and that they are using the most modern and safe materials is certainly an important consideration when choosing materials for parts.
Drag conveyors are required at the base of power boilers, electrostatic precipitators and other power generation equipment. These conveyors move hot fly ash, coal dust, boiler ash, lime and other difficult materials that continuously fall from the bottoms of the equipment. The high temperature and polluted environment would cause traditional grease lubricated bearings to fail, so custom materials are needed for the bearing material for screws, chains and other moving parts.
Although they can span over several industries, these mechanical parts can be composed of similar materials. Specialized carbon graphite is an adaptable material which can be customized to resist oxidation at elevated temperatures and that is dimensionally stable, so that it does not melt like plastic would, and does not have the problems that conventional oil- and grease- lubricated parts would have, particularly in the demands of high-heat environments. These applications are examples of hot industries that benefit from innovating the materials they use to suit their environments, resulting in machines that are safer, and more efficient.
