Carbon-Fiber

Carbon-fiber is a material known for its high strength-to-weight ratio, making it highly desirable in numerous applications where weight savings are crucial. Here's a comprehensive overview:

Composition and Properties

• Carbon-fiber consists of fibers approximately 5-10 micrometers in diameter and composed mostly of carbon atoms. These fibers are arranged in a long, thin structure that provides exceptional tensile strength.
• It is commonly produced by heating polyacrylonitrile (PAN), rayon, or petroleum pitch fibers to extremely high temperatures in an oxygen-free environment. This process, known as carbonization, results in fibers with over 90% carbon content.
• The material boasts properties like high stiffness, excellent fatigue resistance, and low thermal expansion. However, it is also brittle and less resistant to impact compared to materials like metals.

History

• The first commercial carbon-fiber was made in 1960 by Dr. Roger Bacon at Union Carbide, using rayon as a precursor.
• Significant advancements were made in the 1960s and 1970s, particularly in Japan where Toray Industries began producing carbon fibers from PAN in 1964.
• The use of carbon-fiber expanded in the 1970s, with applications in sporting goods, aerospace, and automotive industries.

Manufacturing Process

• The process involves several steps:
  1. Precursor Preparation: The raw material, usually PAN, is spun into fibers.
  2. Stabilization: The fibers are heated in air to oxidize them and stabilize the molecular structure.
  3. Carbonization: The stabilized fibers are heated to temperatures above 1,000°C in an inert atmosphere to drive off non-carbon atoms.
  4. Graphitization: Optional step for higher performance fibers, where the temperature is raised to 3,000°C.
  5. Surface Treatment: Fibers are treated to improve bonding with matrix materials like epoxy.
  6. Sizing: A coating is applied to protect the fibers and improve handling.

Applications

• Aerospace: Used in aircraft components to reduce weight and increase fuel efficiency.
• Automotive: Employed in high-performance vehicles for body parts and structural components.
• Sports Equipment: Found in items like tennis rackets, bicycles, and golf clubs due to its strength and lightness.
• Wind Turbines: Utilized in the blades to reduce weight while maintaining structural integrity.
• Marine: In boats and yachts for hulls and other parts to enhance performance.

Environmental Impact

• The production of carbon-fiber is energy-intensive, contributing to its high cost and environmental footprint.
• Recycling of carbon-fiber is challenging but is being developed to reduce waste and reuse the valuable material.

Sources:

• What is Carbon Fiber?
• Carbon Fibers from Polyacrylonitrile
• The development of carbon fibre technologies

Related Topics

• Fiberglass
• Kevlar
• Composite Materials
• Aerospace Materials