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Federal-Mogul introduces new range of low- and zero-copper brake pad materials to meet new legislation
25 June 2012
|Federal-Mogul developed its Eco-Friction range ahead of legislations set to reduce the amount of copper that can be used in brake pads. Click to enlarge.|
Federal-Mogul Corporation has developed a range of zero-copper and low-copper brake pad formulations using a new tribological fingerprinting process. The company says it has already secured new customer contracts for the low-copper and zero-copper Eco-Friction brake pads for vehicle platforms in North America and Europe.
Copper is a key ingredient in high-performance brake pad formulations, limiting pad and rotor wear, noise and judder and contributing to friction stability over a wide range of operating temperatures. The metal makes up 5 to 20% of the friction material mass in typical Non-Asbestos Organic (NAO) and Low-Steel formulations used in North America, Asia and Europe. The presence of copper in brake pads, however, is being regulated and may eventually be eliminated due to concerns regarding its environmental impact.
|Brake pads and regions|
|In North America and Japan the majority of passenger cars are fitted with Non-Asbestos Organic (NAO) brake pads, also known as ceramic brake pads. These pads provide low-noise operation and improved comfort. Pad and disc wear is lower and service life longer than Low-Steel formulations. However, NAO pads are less stable at maximum stress than Low-Steel and typically have a lower coefficient of friction.|
|Low-Steel brake pad formulations are preferred in Europe, where average speeds are higher and more aggressive performance is required. The pads’ lower iron content provides better friction at high speeds than other pad formulations.|
|Semi-metallic friction pad materials are sold by some aftermarket brands and are fitted as original equipment in certain passenger car markets and for pick-up trucks predominantly in North America. These contain no copper, but do not meet the high-speed performance or comfort noise requirements for some regional passenger car applications.|
Braking releases small amounts of brake lining materials from the contact surfaces of the brakes onto streets, into the air and, eventually, into waterways. Much of this debris contains copper. The copper that ends up in streams, rivers and coastal waters can be toxic to aquatic organisms such as phytoplankton, which make up the base of the food chain and whose health affects entire ecosystems.
In 2010, after a 15-year fight that surfaced with concerns about the San Francisco Bay, California Gov. Arnold Schwarzenegger signed SB346, which requires brake pad manufacturers to reduce the use of copper to no more than 5% by 2021 and no more than 0.5% by 2025. (An estimated 240,000 kg (540,000 lb) of copper were released due to human activity in the San Francisco Bay watershed in 2003, according to a source inventory by the Brake Pad Partnership. Of this amount, 87,000 kg (36%) was copper released from brakes.)
Also in 2010, Washington State passed a law similar to the California law, reducing the use of toxic material in automotive brake pads and shoes, and providing for a phase out of copper over the next 15-20 years. Under the law, brake pads manufactured after 1 January 2021 must not contain more than 5% copper by weight.
Beginning in 2015, the state will review relevant information and consult with a committee of experts to determine if alternative brake friction materials, containing less than 0.5% copper, are available. Eight years after Ecology determines that alternative brake friction materials are available, brake pads containing more than 0.5% copper may not be sold in the state.
Federal-Mogul has succeeded in formulating low- and zero-copper Low-Steel and NAO brake materials for our Eco-Friction range that provide outstanding braking performance and confidence using tribological fingerprinting. This process has given us deeper insight into the complex chemical characteristics and relationships within a brake pad’s friction material and has reduced the time required to identify optimum solutions.—Ramzi Hermiz, Federal-Mogul’s senior vice president, Vehicle Safety and Protection
Considering the principles of friction, lubrication and wear, Federal-Mogul’s tribological fingerprinting process develops datasets for each of the raw materials that make up a brake pad. The company’s scientists then used knowledge of copper’s tribological fingerprint, and how its function changes as the brake pad heats and cools, to screen 1,500 raw materials and identify alternative materials with the same wear and friction pattern across the same temperature range.
Developing these comprehensive datasets has enabled Federal-Mogul to create higher performance brake materials with shorter development times. Standard brake pad product development requires several iterations. The most time-consuming elements are the definition of the formulation’s main structure for wear rate and friction level. Our in-depth understanding of each material’s chemical and physical characteristics in combination with its tribological function removes the trial and error from brake pad development and makes us a better development partner. We are now able to replace a material with very high functionality, such as copper, in considerably less time than competitors, and we can validate an alternative material up to 50% faster depending on the material.—Frank Münchow, director of technology and innovation, Vehicle Safety and Protection, Federal-Mogul
There is no single material that can replace copper, Federal-Mogul notes. Brake pads are a formulation of 20 to 30 different materials, each with different functions. Federal-Mogul’s Eco-Friction range uses a variety of metal sulfides, minerals, abrasives, fibers, ceramic particles and types of graphite to achieve the same wear and friction characteristics as brake pads containing copper.
Given the legislation in some states requiring the phase-out of copper from brake pads, vehicle makers are now specifying brake systems with the regulated levels of copper, making an alternative formulation the standard for future vehicles in many markets, according to Federal-Mogul.
Copper Released from Brake Lining Wear in the San Francisco Bay Area (prepared for the Brake Pad Partnership, 2006)
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