Development and Application Overview of Carbon Fiber Gradient Functional Materials

1. Overview

Functionally Gradient Materials (FGM) represent a novel type of composite material, comprising two or more materials blended together with continuous gradient variations in composition and structure. Developed to meet the demands of high-tech sectors such as modern aerospace, these materials are engineered to operate reliably under extreme conditions. Carbon Fiber Gradient Functional Composites integrate carbon fibers with other materials, adjusting parameters like structure, composition, and density to minimize or even eliminate interfaces, resulting in heterogeneous new composite materials with gradually varying properties.

2. Main Types

Traditional carbon fiber composites are typically uniformly distributed. However, certain applications require the integration of materials with varying physical properties and functionalities. The mismatch in performance of singular carbon fiber composites can lead to structural damage. Therefore, gradient materials have emerged to facilitate the seamless integration of materials with different performances. Historically, the Sword of Goujian, for example, is an early instance of gradient material application, featuring different structural characteristics between the blade and the body. In nature, such as in animal bones, gradient structures are also present. These examples have inspired the development of modern gradient materials.

Image of the Sword of King Goujian

Carbon fiber gradient materials can be classified according to the types and characteristics of their composite materials. Below are some common types and their features:

Table - Overview of Main Carbon Fiber Gradient Materials

Each type of gradient material possesses unique properties, making them suitable for various industrial sectors and environmental conditions. The development and application of these materials are becoming hot topics in the field of materials science and engineering.

3. Technological Frontier

The development in the aerospace sector has led to the emergence of carbon fiber gradient functional composites. These materials are required to withstand extreme temperature conditions, such as the high temperatures found in the nose cones and engine compartments of spacecraft. In 1984, Japanese scholars first proposed the concept of Functionally Gradient Materials (FGMs), which achieve a continuous transition between ceramics and metals by controlling composition and microstructure, effectively alleviating thermal stress and adapting to high-temperature environments.

Despite significant progress, the potential for development of gradient materials remains substantial. Carbon fiber gradient materials have a wide range of applications in heat conduction, electrical conductivity, and electromagnetic shielding, among others. In 2023, the journal "Composite Structures" published research by Professor Zheng Xitao's team from the Institute of Aircraft Composite Material Structure at Northwestern Polytechnical University. This research, based on gradient arrays of carbon fiber composites, proposed a new type of lightweight stealth load-bearing integrated design.

Diagram of Grid Absorber Structure: (a) Periodic Structure; (b) Gradient Carbon Fiber Strip Array

4. Raw Material Market

Currently, carbon fiber gradient materials are still in a niche market with limited large-scale data available. This paper analyzes the overall market situation of carbon fiber.

Since the 21st century, research and application of carbon fiber in China have developed rapidly. The increasing demand for military aircraft, the development of aerospace technologies led by the Beidou Navigation System, the rapid growth of civilian aviation, and the substantial demand for wind turbine blades have prompted national investments across the entire carbon fiber industry chain. In 2021, Jiangsu Hengshen increased both output and production, achieving profitability for the first time since its establishment and marking the first industry-wide profitability for domestic fibers; in February 2022, the world's first carbon fiber material-made torch shell for the Beijing Winter Olympics was unveiled. Meanwhile, carbon fiber companies are intensifying their development efforts: in September 2021, China National Building Material's Xining ten thousand tons of carbon fiber base was put into operation; in October, Jilin Chemical Fiber's first carbonization line for the annual production of 600 tons of high-performance carbon fiber was successfully tested; in January 2022, Shanghai Petrochemical's 12,000 tons/year of 48K large tow carbon fiber production equipment was delivered; in March 2022, Xinjiang Longju New Materials' 50,000 tons/year high-performance carbon fiber project resumed, and in April 2023, Xinjiang Longju's 48K large tow carbon fiber production line was successfully tested; in April 2023, the Lianyungang 30,000 tons carbon fiber project of Zhongfu Shenying officially started, and in May, the Xining 25,000 tons project was fully operational, with Zhongfu Shenying's annual capacity expected to reach 28,500 tons/year by the end of 2023.

Figure: Geographic Distribution of Major Carbon Fiber Enterprises

5. Conclusion

With the increasing demands for material performance in high-technology fields, Carbon Fibre Gradient Functional Composites have emerged, bringing a new direction to material science. These materials combine the advantages of different substances through a gradient composition, optimizing both performance and applicability. The development of carbon fibre gradient materials aims to meet the demands of industries such as aerospace in extreme conditions.

The diversity of these materials is reflected in the combination of carbon fibre with various materials such as ceramics, metals, polymers, etc. This combination endows the materials with characteristics such as high-temperature resistance, high mechanical strength, and good toughness, making them widely applicable in fields such as aerospace, automotive industry, and sports equipment. The research on gradient materials is inspired not only by natural structures, like the gradient structure of animal bones but also by historical applications, such as the complex material structure of the Sword of Goujian. Technically, significant progress has been made in the development of carbon fibre gradient materials. For example, recent research by the Institute of Composite Material Structure for Aeronautical Engineering at Northwestern Polytechnical University has showcased the potential of these materials in electromagnetic wave absorption and mechanical performance enhancement. On the market level, although carbon fibre gradient materials are currently in a niche market, with continuous technological advancement and expanding applications, a broader development prospect is expected. Overall, the development of Carbon Fibre Gradient Functional Composites is an important milestone in the field of material science, with a wide application prospect in multiple high-tech fields. With further research and technological innovation, these materials may demonstrate their unique value in even more fields in the future.

This article is collected by China Composites Industry Association from the network, the article is not used for commercial purposes, only for the industry to communicate, please specified.