by Kat Griffin Kat Griffin

Understanding Graphite as a Material for Military Components


>>>>Graphite, a crystalline form of carbon, has garnered significant interest in the military sector due to its unique combination of properties. Known for its excellent thermal and electrical conductivity, high lubricity, and outstanding resistance to heat and corrosion, graphite stands out as a versatile material for various military applications. Its ability to perform under extreme conditions makes it ideal for components in advanced weaponry, aerospace engineering, and electronic warfare systems.

In 2021, President Joe Biden signed an executive order aimed at strengthening critical US supply chains. Graphite was identified as one of four minerals considered essential to the nation’s “national security, foreign policy and economy.” Graphite is:

    • 1 of 14 listed minerals for which the US is 100% import dependent.
    • 1 of 9 listed minerals meeting all six of the industrial/defense sector indicators identified by the US government report.
    • 1 of 4 listed minerals for which the US is 100% import-dependent while meeting all 6 industrial/defense sector indicators.
    • 1 of 3 listed minerals which meet all industrial/defense sector indicators

Military and Defense Uses

A report from the Hague Centre for Strategic Studies highlights that aluminum and natural graphite are the two most used materials in the defense industry. These materials are commonly found in a wide range of military hardware, including aircraft, helicopters, aircraft and helicopter carriers, amphibious assault ships, corvettes, offshore patrol vessels, frigates, submarines, tanks, infantry fighting vehicles, artillery, and missiles.

Graphite in Firearms

Graphite is a game-changer in firearms technology. Imagine a soldier relying on their weapon in extreme conditions – graphite makes this possible. Used in gun barrels, bolt carriers, and suppressors, graphite’s high lubricity significantly reduces friction and wear, essential for the longevity of gun barrels that endure high temperatures and pressures during firing. Graphite-based lubricants ensure smooth operation, reducing maintenance needs. This technology isn’t just theoretical – specific firearms with graphite components showcase improved accuracy, reliability, and extended service life, proving graphite’s practical benefits in the field.

Graphite in Aircraft and Helicopters

The aerospace sector leverages graphite composites extensively in airframe and structural components. The integration of graphite helps achieve significant weight reduction, leading to improved fuel efficiency and maneuverability of aircraft and helicopters. Graphite’s excellent thermal conductivity aids in effective heat dissipation, particularly in high-stress areas such as engine components and leading edges. Military aircraft like the F-22 Raptor and the Eurofighter Typhoon have utilized graphite composites to enhance their performance, underscoring the material’s critical role in modern aviation technology.

Graphite in Submarines and Naval Vessels

Graphite is utilized in submarine hulls and other structural components due to its exceptional stealth and durability properties. Its application in submarine hulls helps reduce acoustic signatures, enhancing stealth capabilities essential for modern naval operations. Cooling systems and power management also use graphite due to its excellent thermal and electrical conductivity. Case studies of advanced naval vessels, such as the Virginia-class submarines, highlight the strategic advantages gained from incorporating graphite materials in their construction and systems.

Graphite in Artillery and Missiles

In artillery and missile systems, graphite components play a pivotal role in enhancing performance and reliability. Graphite’s superior thermal management and electrical conductivity are crucial for missile guidance systems, ensuring precise and accurate targeting. In artillery, graphite is utilized in barrels and other critical components to endure the extreme temperatures and pressures generated during firing. This application enhances the durability and longevity of the equipment. These applications demonstrate graphite’s ability to meet the stringent demands of modern military technology.

Emerging Technologies and Future Trends

Innovations in graphite-based materials continue to drive advancements in military applications. The development of nanocomposites and advanced manufacturing techniques opens new possibilities for utilizing graphite in cutting-edge defense technologies. Potential future uses include next-generation weapon systems, enhanced protective gear, and advanced electronic warfare systems. As research and development in graphite materials progress, the military sector stands to benefit. The ongoing evolution of this versatile material will enhance various military applications.

Conclusion

Graphite is vital for military applications due to its unique properties, enhancing defense system performance and reliability. Advancing graphite-based materials is key to maintaining technological superiority and addressing future national security challenges, highlighting the need for continued innovation.

by Kat Griffin Kat Griffin

Tapping Electrodes: Applications & Types

copper impregnated tapping electrodesIn the context of the Electrical Discharge Machining (EDM) industry, tapping electrodes refer to a specific type of electrode used in EDM processes. They are used to remove material from a workpiece in order to shape it into a desired form.

In machining processes, tapping electrodes play a crucial role in creating precise and accurate threads in a variety of materials, including metals that are difficult to machine using conventional methods. This is particularly important in manufacturing industries where threaded components are commonly required, such as aerospace, automotive, and tooling.

 

Materials

Tapping electrodes used in EDM can be categorized based on the materials they are made of. Below are just some common types of tapping electrodes along with the materials typically used for their construction:

 

Graphite/Copper Graphite

Graphite tapping electrodes are widely used due to their excellent electrical conductivity and high temperature resistance. They are suitable for machining a wide range of materials, including hardened steels, aluminum, and other alloys. Graphite electrodes offer good wear resistance and can maintain their shape and dimensions during EDM operations.

Copper Tungsten

Copper tungsten is recommended for tapping tungsten carbide/carbide, titanium, and refractory metals, especially in smaller sizes where metals offer strength and maintain sharp edges. This material blends the high electrical conductivity of copper with the exceptional hardness and wear resistance of tungsten. These electrodes exhibit superior thermal conductivity, wear resistance, and compatibility with a diverse range of materials, making them ideal for precise material removal in EDM operations. 

The choice of electrode material depends on factors such as the specific machining requirements, the properties of the workpiece material, and the desired surface finish.

 

Factors Influencing Performance

Several factors influence tapping electrode performance in EDM, including material composition, electrical discharge parameters, workpiece material, EDM fluids, machining environment, machine setup and maintenance, and operator skill. The material from which the electrode is made affects its conductivity, hardness, and wear resistance, while its geometry impacts access to tight spaces and material removal efficiency. Proper selection of electrical discharge parameters and EDM fluids, along with stable machining conditions, is crucial for achieving optimal results. Additionally, maintaining equipment and ensuring operator proficiency are essential for maximizing tapping electrode performance and achieving high-quality machining outcomes.

Overall, considering and effectively managing these factors is essential for maximizing tapping electrode performance and achieving high-quality results in EDM and other machining operations.

 

Contact Us for a Quote Today

MWI provides tapping electrodes, including standard and orbital types, available in EC-15, EC-15C, and copper tungsten, which are customized to order upon request. We also offer these options in metric sizes. Check out our EDM Tapping Electrodes data sheet for more information. For tapping electrode inquiries, please reach out to us today at sales@mwi-inc.com.

by Kat Griffin Kat Griffin

Why is graphite used for electrodes?

electrode made out of graphite
Electrodes can be made from any conductive material. Depending on the nature of the application, electrodes are typically from graphite. Noble metals like gold, silver or platinum can be used but are very expensive. Copper, titanium and brass are other options, but they are also costly.

Graphite is used as an electrode material because it is a good conductor of electricity, is chemically stable, and can withstand high temperatures. It also has a low reactivity and thermal expansion coefficient, making it suitable for electrode use in electrochemical cells.

Graphite is a Good Conductor of Electricity

Graphite’s unique structure, with layers of carbon atoms arranged in hexagonal, allows the electrons to move freely, making it a good conductor of electricity and useful as an electrode material.

In graphite, the carbon atoms are arranged in layers, retaining their structure through covalent bonds. A significant feature of graphite’s structure is the number of delocalized electrons present. Graphite requires only three of its outer energy electrons to bond, leaving the fourth free to act in a delocalized manner. Delocalized electrons are not readily associated with a particular atom and move freely. These electrons enable graphite to exhibit a high level of conductivity, explaining why the material is frequently used for electrodes.

Graphite Electrode Materials

Check out MWI’s graphite product guide that contains information for our Electro-Carb “EC” family of graphite electrode materials. Graphite grades include EC-4, EC-12, EC-14, EC-15, EC-15C. EC-16, EC-17, HK-6, and HK-6C.

DOWNLOAD OUR GRAPHITE PRODUCT GUIDE
by Kat Griffin Kat Griffin

What are the Structure and Properties of Graphite?

Structure and Properties of Graphite

Carbon-graphite offers a unique combination of physical, chemical and mechanical characteristics found in no other material. One particular characteristic is its structure.

Graphite has a layered structure. In each layer, each carbon atom is bound to three others. This results in a two-dimensional network of hexagons. Within each layer, there are strong bonds, but between the different layers, the bonds are fragile. Thus, the layers can easily be shifted against each other and separated. This structure is why graphite is very soft and even used as a lubricant. But graphite has other unique characteristics as well:

Electrical Conductivity

The fact that graphite is electrically conductive results from its atomic structure. Each carbon atom in a graphite crystal has four valence electrons, also called outer electrons, which can form bonds with neighboring atoms. However, only three of the four valence electrons enter into a bond, while the fourth electron remains freely mobile and thus allows electricity to be conducted.

Thermal Conductivity

Graphite has excellent thermal conductivity combined with high-temperature resistance. Graphite does not have a melting point; it changes from the solid state directly into the gaseous state. This process is called sublimation. In an inert gas atmosphere, graphite becomes plastically deformable starting at 2500 °C. At temperatures above 3750 °C, graphite sublimates even without oxygen.

Chemical Resistance

Graphite is one of the most chemically resistant materials. It is resistant to almost all media of organic chemistry. These typically include the intermediate and/or end products in the petrochemicals, coal refining, plastics industry, the production of paints, coatings, refrigerants, and antifreeze, but also in the cosmetics and food industries. In addition, it is resistant to most inorganic media, such as non-oxidizing acids, alkalis, aqueous salt solutions, and most technical gasses.

Important Chemical Reactions

Reaction with Air
Carbon in the form of graphite, burns in the air to form Carbon Monoxide and Carbon Dioxide depending upon the availability of air or oxygen. Diamond is a type of carbon that, when heated to 600°C-800 °C, also burns in the air.

  • C(s)+O2→CO2(g)
    • When the availability of air or oxygen is limited, incomplete combustion occurs, resulting in carbon monoxide, CO.
  • 2C(s)+O2(g)→2CO(g)
    • This reaction is important in industrial processes, where air is passed through hot coke. The resulting producer gas is a mixture of carbon monoxide, carbon dioxide, nitrogen, along with small amounts of hydrogen (H2), methane (CH4), and oxygen (O2).
Reaction with Water

Carbon in the form of graphite doesn’t react with water in normal conditions. Under certain circumstances, the given reaction becomes possible and forms water gas which is a mixture of carbon monoxide and hydrogen gas.

  • C+H2O→CO+H2
Reaction with Halogen

At elevated temperatures, graphite reacts with fluorine (F2) to form carbon tetrafluoride (CF4), along with smaller amounts of C2F6 and C5F12.

  • C (s) + excess F2 (g) → CF4 (g) + C2F6 + C5F12

Other halogens do not seem to react with graphite.

Reaction with Acids

Mellitic acid, C6(CO2H)6, is formed when graphite combines with the oxidizing acid hot concentrated nitric acid.