Main research directions of friction materials
In order to adapt to the development of the machinery industry, improve and explore new friction materials, focus on the following aspects: improve the wear resistance of materials that determine the service life of the brake device; obtain a sufficiently high and stable friction coefficient to ensure the work of the brake and transmission device Reliability and stability.
The heat resistance of friction materials can basically be characterized by two indicators: high temperature oxidation resistance and the ability of the metal matrix as the basis of the material to maintain sufficient mechanical strength. In order to reach higher operating temperatures, there has been a transition to more refractory metals and more complex alloying. For example, iron-based materials are often used to replace bronze-based materials under heavy loads: in order to increase the working temperature and mechanical strength limit of copper-based materials, aluminum is used instead of tin to alloy copper; iron-based materials are added with nickel, cobalt, chromium, Elements such as manganese, tungsten, and molybdenum alloy the iron-based friction material to further improve the thermal stability and mechanical strength of the iron-based friction material.
When iron-based friction materials come into contact with iron at high temperatures, unstable graphite also tends to be replaced with inert anti-seize agents (such as boron nitride). Under heavy loads, nickel-based and tungsten-based powder metallurgy friction materials are proposed. In order to improve its oxidation resistance, friction materials based on stainless steel fibers have been proposed. For wear resistance, multiple alloying is also used to increase the strength of the friction material metal matrix.
In order to improve and stabilize the friction coefficient, a lot of research work has been carried out on the exploration of new friction agents and anti-seize agents. In order to improve the friction coefficient of iron-based friction materials, such compounds are added: such as boron carbide, silicon carbide, zirconium carbide, boron nitride and so on. For heavy-duty work, silicon dioxide as a friction agent is replaced with carbides and nitrides.