Ⅰ. Basic Characteristics of Carbon Fiber: The Structural Mystery Behind Its High Strength
Carbon fiber has excellent specific strength and specific modulus, and is the core raw material of modern high-performance composite materials. On the production line of our factory, every carbon fiber used is composed of thousands or even tens of thousands of monofilaments with a diameter of only about 7 microns. These monofilaments are mainly composed of carbon elements. Carbon atoms are arranged through a special crystal structure, forming a highly oriented microcrystalline structure. This unique structure endows carbon fibers with extremely high tensile strength, typically reaching over 3500MPa, and some high-performance carbon fibers can even exceed 7000MPa, which is dozens of times the strength of steel, while the density is only about a quarter of that of steel.
The high performance of carbon fiber not only stems from its microstructure but is also closely related to the manufacturing process. From the preparation of PAN precursor to key links such as pre-oxidation and carbonization, every step requires strict control of process parameters.
Ⅱ. Investigation of Carbon Fiber Aging Phenomenon: Does It Really Become Brittle Over Time
In practical applications, whether carbon fiber will become brittle over time is a focus of concern for many customers. From the perspective of materials science, the chemical properties of carbon fibers themselves are relatively stable, and the carbon-carbon bonds have a high bond energy. Under the ideal environment of normal temperature and pressure without external interference, carbon fibers will not show significant performance degradation. However, in actual use, due to the influence of various environmental factors, mechanical loads and manufacturing process defects, carbon fibers may indeed age and become brittle.
Through long-term experimental research and tracking of practical application cases, we have found that the aging process of carbon fiber is a gradual one and does not show obvious brittleness in a short period of time. Under certain extreme conditions, the performance degradation of carbon fiber will accelerate, while under appropriate usage and maintenance conditions, its performance can remain stable for a relatively long time.
Ⅲ. Key Factors Affecting the Brittleness of Carbon Fibers
Environmental factors: Long-term erosion by temperature, humidity and chemical media
Environmental factors have a significant impact on the aging of carbon fibers. High-temperature environments accelerate the molecular movement within carbon fibers, causing their structure to gradually relax and thereby reducing the material's strength. We conducted tests on carbon fibers in a simulated high-temperature environment in the laboratory. When the temperature exceeded 200℃, after 1000 hours of continuous action, the tensile strength of the carbon fibers decreased by approximately 15%.
Humidity should not be ignored either. Moisture in a humid environment can seep into the interface of carbon fiber composites, leading to a decrease in the bonding force between the resin matrix and the carbon fibers, causing defects such as delamination, and thereby affecting the overall performance of the material. In addition, chemical media such as acid and alkali solutions, organic solvents, etc. can undergo chemical reactions with carbon fibers or resin matrices, destroying their internal structures and accelerating the aging and brittleness of the materials.
Mechanical factors: Fatigue damage under continuous stress
In practical use, carbon fiber products often bear various mechanical loads. When carbon fibers are under continuous stress for a long time, fatigue damage will occur even if the stress level is lower than their ultimate strength. This kind of fatigue damage is manifested as the initiation and expansion of tiny cracks inside carbon fibers. Over time, the cracks gradually expand, eventually leading to brittle fracture of the material.
We once produced carbon fiber automotive parts for a certain car manufacturer. During the subsequent usage tracking, we found that the fatigue life of the components that were subjected to vibration and alternating stress for a long time was significantly shortened. Through the analysis of the failed components, it was confirmed that fatigue damage is one of the important reasons for the brittleness of carbon fibers.
Process factors: Manufacturing defects accelerate material aging
The quality of the manufacturing process directly affects the quality and service life of carbon fiber products. During the preparation process of carbon fiber composites, if the impregnation of the resin matrix and carbon fibers is not uniform, it will lead to insufficient interfacial bonding strength. If the temperature and pressure are not properly controlled during the curing process, defects such as pores and delamination may occur. These manufacturing defects can become stress concentration points, accelerating the aging and damage of the material during use.
Our factory has established a strict quality control system. From raw material inspection to finished product testing, every link is strictly controlled. Through advanced non-destructive testing techniques, such as ultrasonic testing and X-ray testing, defective products can be detected and eliminated in a timely manner to ensure that every carbon fiber product leaving the factory has reliable quality.
Ⅳ. Actual Case Analysis: Aging Manifestations of Carbon Fibers in Different Scenarios
Aerospace field: Long-term tests in extreme environments
In the aerospace field, carbon fiber composite materials are widely used in key parts such as aircraft structural components and rocket bodies. These components need to serve for a long time in extreme high-altitude environments and are exposed to various harsh conditions such as low temperatures, high vacuum, and ultraviolet radiation.
The wings of a certain model of aircraft were made of carbon fiber composite materials produced by us. During the inspection after 10 years of service, it was found that the coating on the surface of the wings had aged and peeled off to a certain extent, and there were tiny delamination phenomena inside the carbon fiber composite materials in some areas. After analysis, the main reason is that long-term ultraviolet radiation has led to a decline in the performance of the coating, which in turn exposes the carbon fiber to harsh environments and accelerates the aging of the material. Through timely repair and protective treatment, the performance of the aircraft wing was effectively restored.
Sports goods field: Frequent use and daily wear and tear
In the field of sports goods, carbon fiber is often used to manufacture products such as golf clubs and bicycle frames. These products are frequently subjected to shock and vibration during use, and at the same time, they are also affected by daily wear and tear and environmental changes.
We once received feedback from a customer that the carbon fiber bicycle frame they had used for three years had experienced a decline in performance. Upon inspection, it was found that there were multiple scratches and wear on the surface of the frame. These damages made it easier for moisture to seep into the material, accelerating the aging of the carbon fiber. By carrying out surface repair and protective treatment on the frame and providing customers with usage and maintenance suggestions, the service life of the frame has been effectively prolonged.
Automotive industry field: Performance changes under complex working conditions
In the automotive industry, carbon fiber composite materials are applied to parts such as the chassis and body of automobiles to achieve lightweight and enhance performance. During the driving process, cars will encounter various complex working conditions, such as the vibration of bumpy roads and the high-temperature engine compartment environment.
The carbon fiber battery tray we produced for a certain new energy vehicle manufacturer was tested after five years of use. It was found that under the long-term effect of vibration and temperature changes, the carbon fiber in some local areas of the tray showed slight fatigue damage, but the overall performance still met the usage requirements. This is attributed to the optimized process and structural design we adopted during the manufacturing process, which effectively enhanced the fatigue resistance of the product.
V. Effective Measures to Delay the Brittleness of Carbon Fibers
Optimize the manufacturing process to ensure quality from the source
During the manufacturing process, we constantly optimize the process parameters to enhance the impregnation effect between the resin matrix and the carbon fiber and ensure the interfacial bonding strength. Advanced curing processes are adopted, with strict control over temperature, pressure and time to reduce the occurrence of defects such as pores and delamination. At the same time, strengthen the quality control of raw materials, select high-quality raw filaments and resins, and ensure the quality of carbon fiber products from the source.
Surface protection treatment to enhance anti-aging ability
Surface protection treatment of carbon fiber products is an important measure to delay their aging. We apply high-performance coatings, film application and other methods to provide physical barriers for carbon fibers, preventing erosion by moisture, chemical media and ultraviolet rays. For instance, a new type of nano-coating we have developed can effectively enhance the UV resistance and corrosion resistance of carbon fiber products, extending their service life by more than 30%.
Use and maintain reasonably to extend service life
For users of carbon fiber products, reasonable use and regular maintenance are of vital importance. During use, overloading and improper operation should be avoided to prevent damage to the material. Regularly inspect and maintain carbon fiber products, promptly repair surface damage, clean surface dirt, and keep the material in good condition. We provide customers with detailed usage and maintenance manuals as well as professional technical guidance to help them use and maintain carbon fiber products correctly.
Ⅵ. Conclusion: Scientifically Understand the aging characteristics of carbon fibers
To sum up, carbon fibers do have the possibility of becoming brittle over time during actual use, but this process is influenced by a combination of multiple factors. By optimizing the manufacturing process, strengthening surface protection and reasonable use and maintenance, the aging of carbon fibers can be effectively delayed and their service life can be prolonged.
As a professional factory with many years of experience in carbon fiber production, we, relying on advanced technology and rich practical experience, can not only produce high-performance carbon fiber products, but also provide customers with comprehensive technical support and solutions. If you have any questions about the performance, use and maintenance of carbon fiber, please feel free to contact us at any time. We will serve you wholeheartedly!
