Asbestos was added as an common ingredient to Brake Pads post-WWI, as car speeds began to increase, because research showed that its properties allowed it to absorb the heat (which can reach 500 °F) while still providing the friction necessary to stop a vehicle. However, as the serious health-related hazards of asbestos eventually started to become apparent, other materials had to be found. Asbestos brake pads have largely been replaced by non-asbestos organic (NAO) materials in first world countries. Today, brake pad materials are classified into one of four principal categories, as follows:
Non-metallic materials - these are made from a combination of various synthetic substances bonded into a composite, principally in the form of cellulose, aramid, PAN, and sintered glass. They are gentle on rotors, but produce a fair amount of dust, thus having a short service life.
Semi-metallic materials - synthetics mixed with varying proportions of flaked metals. These are harder than non-metallic pads, more fade-resistant and longer lasting, but at the cost of increased wear to the rotor/drum which then must be replaced sooner. They also require more actuating force than non-metallic pads in order to generate braking torque.
Fully metallic materials - these pads are used only in racing vehicles, and are composed of sintered steel without any synthetic additives. They are very long-lasting, but require more force to slow a vehicle while wearing off the rotors faster. They also tend to be very loud.
Ceramic materials - Composed of clay and porcelain bonded to copper flakes and filaments, these are a good compromise between the durability of the metal pads, grip and fade resistance of the synthetic variety. Their principal drawback, however, is that unlike the previous three types, despite the presence of the copper (which has a high thermal conductivity), ceramic pads generally do not dissipate heat well, which can eventually cause the pads or other components of the braking system to warp.However, because the ceramic materials causes the braking sound to be elevated beyond that of human hearing, they are exceptionally quiet.
Auto Brake Pads,Car Pad Shims,Brake Pad Shims,Autozone Brake Pads LIXIN INDUSTRIAL & TRADE CO.,Limited , https://www.jmsparkplug.com
KAIST stated that the city of Maiaron, Texas, USA plans to put three OLEV buses into operation on the city's 16km bus route from 2013 onwards, and decided to purchase the OLEVTECHNOLOGY subsidiary of KAIST in Massachusetts. Technology and related vehicles, procurement amounted to 2.11 million US dollars.
OLEV full name On-Line Electric Vehicle, is a non-contact electromagnetic induction powered electric vehicle, the principle is to use the electromagnetic induction can provide power between the power supply coil and the power receiving coil. That is, one power receiving coil device is mounted on the chassis of the automobile, and the other power feeding coil device is buried under the road. When the electric vehicle reaches the power supply coil device, the power receiving coil can receive electromagnetic waves of the power supply coil, and thus The battery is charged. KAIST's OLEV technology was rated as one of the world's 50 largest inventions by the US "Times" magazine last year.
Korean electromagnetic induction electric vehicle technology products are exported overseas
According to the Yonhap News Agency, the OLEV technology product for electric vehicles developed by the Korea Institute of Science and Technology (KAIST) will be exported to the United States.