Do You Use Your Brakes Daily? Have You Experienced the Power of
Brake pad materials have evolved from asbestos and semi-metallic to sintered metal, and further to carbon-carbon (C/C) and carbon-ceramic composites. Sintered metal brake materials suffer from drawbacks such as a tendency to bind at high temperatures, susceptibility to fade in friction performance, significant loss of strength at elevated temperatures, poor thermal shock resistance, and short service life. Meanwhile, C/C composite brake materials face issues like low static and wet friction coefficients (wet friction can degrade by about 50% compared to dry), a large thermal mass, poor oxidation resistance, long production cycles, and high production costs, which have constrained their further development and application.
Carbon-ceramic (Carbon-SiC) composite brake materials, developed in the 1990s, are a multi-phase composite material using high-strength carbon fiber as the reinforcement and materials like pyrolytic carbon and silicon carbide (SiC) as the matrix. Essentially an evolution of C/C composite brake materials, they incorporate SiC, a ceramic material with excellent oxidation resistance, into the matrix, hence also known as ceramic brake pads. They retain the advantages of C/C composites, such as low density and high-temperature resistance, while overcoming the drawbacks of low static friction coefficient, significant wet-friction degradation, insufficient service life, and poor environmental adaptability associated with C/C materials, establishing themselves as the next generation of braking materials.
The Origin of Carbon-Ceramic Brakes
Carbon-ceramic brake technology originally stemmed from aerospace. In 1969, the supersonic airliner Concorde, jointly developed by Aérospatiale (France) and British Aircraft Corporation, took its maiden flight. This extremely fast aircraft could travel from London to New York in under three hours, setting records for commercial flight speed. Such a high-performance aircraft naturally required powerful acceleration. Its average takeoff speed reached around 400 km/h (250 mph), with similar approach speeds for landing. To bring this 185-ton airliner to a stop from such high speeds demanded a robust and heat-resistant braking system. They turned to Dunlop, which developed the world's first aviation carbon-ceramic brake system for the Concorde. This system could stop the airliner from 305 km/h (190 mph) within 1600 meters.
Clearly, carbon-ceramic brake technology proved successful in aerospace. However, at that time, disc brake systems for cars were just beginning to gain popularity in passenger vehicles, making them incompatible with the prohibitively expensive carbon-ceramic brakes. Fast forward to 1976, when legendary car designer Gordon Murray was tackling weight reduction for the Brabham Formula 1 team. He experimented with using carbon-ceramic material to make brake calipers, as carbon-ceramic discs weighed almost half as much as steel ones. Successfully implementing them in F1 could significantly boost performance.
After some effort, he found a materials company called Hitco, which produced solid carbon-ceramic discs. They were mounted to the wheels using aluminum bells. Thus, the first automotive carbon-ceramic brake system was fitted to the Brabham team's new F1 car for the season, the BT45. Although the final results weren't stellar, it didn't stop carbon-ceramic brakes from gradually being adopted by other teams, eventually becoming the dominant brake material throughout F1. For a long time afterward, carbon-ceramic brakes remained confined to the racetrack. Besides their exorbitant cost, the primary reason for their absence in road cars was likely that consumer vehicles simply didn't require such extreme performance back then. It wasn't until 1997 that two component manufacturers began researching carbon-ceramic technology for the consumer market: SGL Carbon, a world-leading manufacturer of carbon products, and the well-known Brembo. SGL, in collaboration with Porsche, unveiled the world's first consumer carbon-ceramic brake disc at the Frankfurt Motor Show in 1999, just a year after project initiation. In 2000, it was fitted to Porsche's latest high-performance sports car, the 996 Turbo. In 2002, Brembo introduced its production-ready product, partnering with Ferrari. Their first carbon-ceramic brakes were equipped on the Ferrari Enzo. Given that the Enzo was a hypercar named after the company's founder, its adoption of Brembo's new product was a testament to the system's formidable performance.
Even after over two decades of consumer availability, the cost of carbon-ceramic brakes remains high due to their complex manufacturing process. To this day, these systems are mostly found on a limited number of high-performance cars. However, with the proliferation of new energy vehicles (NEVs) and ongoing advancements in carbon-ceramic technology and cost control, carbon-ceramic brake pads are beginning to make inroads in the NEV sector. In 2022, Tesla offered a new Carbon Ceramic Brake Kit for its Model S Plaid. This system includes components like carbon-ceramic brake discs, calipers, pads, aluminum alloy (or alloy steel) hats, and mounting hardware, with a set for each wheel. Tesla's pioneering commercial application of this system led some to believe it could spearhead a braking upgrade trend for electric vehicles.
Advantages and Disadvantages of Carbon-Ceramic "Going Mainstream"
Some describe carbon-ceramic brake pads as a new braking material "lifted" by electric vehicles—not in the sense of hype, but rather catching a ride on the tailwinds of the EV revolution.
In the era of traditional internal combustion engine (ICE) vehicles, even after another 10 or 20 years, carbon-ceramic brakes might have remained a "luxury item." However, in the EV era, two key advantages seem to have smoothed the path for ceramic brake pads to go mainstream. First is the advantage of lightweighting. In the ICE era, research by the European Automobile Manufacturers' Association suggested that reducing a car's weight by 100 kg could lower fuel consumption by approximately 0.4L/100km and reduce CO2 emissions by about 1 kg. Therefore, vehicle lightweighting effectively reduces carbon emissions. Compared to ICE vehicles, while NEVs eliminate the engine and transmission, they add a battery pack, often making them heavier. Consequently, lightweighting is even more critical for the development of energy-saving and new energy vehicles.
Carbon-ceramic brakes can effectively reduce unsprung weight (the weight below the suspension), making them particularly well-suited for NEVs and helping alleviate range anxiety. A traditional cast iron brake disc typically weighs over 10 kg, while a carbon-ceramic disc weighs only around 6 kg—a roughly 50% reduction. Four discs can save about 20 kg. Reducing unsprung mass has a much greater effect on handling and ride than reducing sprung mass (the weight supported by the suspension), often estimated with a multiplier effect (e.g., 1 kg of unsprung mass saved feels like saving 5-10 kg of sprung mass). It's like the difference between carrying a weight on your back versus having it strapped to your feet while walking; the perceived burden is different. Therefore, the 20 kg reduction from carbon-ceramic discs can have an effect equivalent to reducing the vehicle's body weight by 100 kg or more, potentially extending range by several tens of kilometers. Secondly, one of the biggest advantages and selling points of electric vehicles compared to ICE vehicles is their significantly stronger acceleration. Nowadays, $40,000 EVs can achieve 0-60 mph times around 4 seconds, rivaling supercars. The ability to go fast must be matched by the ability to stop effectively, so the demand for braking performance in EVs is increasing. Ceramic brake pads are better equipped to meet this requirement. In practical use, braking is the process of converting kinetic energy into thermal energy through friction. If the brake system cannot dissipate this heat quickly, braking performance suffers. When bringing a one-ton-plus vehicle from highway speeds to a complete stop, the braking system must convert massive kinetic energy into heat.
Under hard braking, conventional brake discs are prone to overheating and thermal fade, where braking performance diminishes significantly. Ceramic brake discs offer excellent resistance to thermal fade, with heat resistance many times greater than that of conventional discs. Furthermore, ceramic discs can generate maximum braking force early in the braking process, leading to overall faster braking and shorter stopping distances compared to traditional systems.
Of course, the disadvantages of ceramic brake pads are also quite apparent—primarily, they are very expensive. This is due to factors like complex manufacturing processes, production difficulties, and long production cycles. Leading overseas manufacturers of carbon-ceramic brake discs primarily supply high-end sports car makers, with products commanding very high prices. For example, a single carbon-ceramic disc from a leader like Brembo can cost over $15,000. Therefore, the high price has been the main reason ceramic brake pads haven't become commonplace.
Significant Market Potential and Room for Domestic Alternatives
Initially, due to multiple barriers including complex processes, manufacturing difficulties, and long production cycles, the cost of carbon-ceramic brake pads remained high. Prior to Tesla's commercial adoption, carbon-ceramic brake systems were mainly used in aerospace, high-speed rail markets, and within the automotive sector, only in race cars and supercars from brands like Porsche, Bentley, Bugatti, and Lamborghini. With the rapid development of China's new energy vehicle industry, factors such as expanding scale, technological upgrades, increased automation, and declining carbon fiber prices are expected to significantly reduce costs in the coming years. The penetration rate of carbon-ceramic discs is anticipated to rise steadily. According to relevant industry forecasts, the domestic market in China is projected to reach approximately RMB 7.8 billion by 2025, potentially exceeding RMB 20 billion by 2030. This could represent an entirely new market. Once breakthroughs are achieved, it could become a key selling point for automotive safety, with growth rates potentially exceeding expectations.
Simultaneously, this sector represents a blue ocean market with substantial room for domestic substitution. Constrained by barriers like complex processes and manufacturing difficulties, few Chinese companies can mass-produce carbon-ceramic discs. Major global suppliers of carbon-ceramic composite brake discs include Italy's Brembo and the UK's Surface Transforms Plc. Few domestic companies in China have mastered the technology for producing high-performance carbon-ceramic composite brake discs, indicating significant potential for import substitution. Historically, China's brake materials industry has lagged internationally, primarily due to lower automotive production volumes, fewer model variations, and slower industry development in the past, which limited advancements in braking systems. In recent years, China's automotive brake materials industry has made considerable progress, focusing on developing new materials. Most brake material manufacturers have strengthened their R&D capabilities, technological levels, production equipment, and processes, leading to gradual improvements in product quality and more stable performance. As domestic companies continue to make technological breakthroughs in this field and with the trend of increased features, higher specifications, and intelligentization in new energy vehicles, the penetration rate of domestically produced carbon-ceramic discs in China's NEV market is expected to keep increasing.