Preparation Of The Cu-based Friction Material For Wind Turbines And Study On The Friction And Wear Performance

The wind energy which is a clean and green renewable energy will make a significant contribution to energy structure adjustment, environmental protection and economy improvement. The rapid development of wind power industry makes wind power installed capacity increasing. So, the friction material for wind turbine braking is required strictly. Nowadays, most of the friction materials for wind turbines are imported. So, the development of the friction material for high power wind turbines will play an important role in developing the wind turbine braking technology and improving the economic benefit.In this paper, Cu-based friction materials for wind turbines were prepared by powder metallurgy technology. The copper which has the good thermal conductivity was chosen as the matrix. The tin and iron on the matrix improved the strength of the matrix and the zircon, alumina and graphite improved the friction and wear properties. The wear tests were conducted by the wear tester. The friction surface morphology was observed by means of the scanning electron microscopy. The effect of graphite content and graphite size on the friction and wear properties at the different speed was studied by comparison. The best ratio of ingredients of the powder metallurgy friction material for wind turbines was determined.The conclusions can be drawn as the following:1. The microstructure of copper-based friction materials for wind turbines which was prepared by powder metallurgy technology is uniform. The matrix is Cu. Sn and Fe improves the strength of matrix. The distribution of the graphite which is chosen as the lubrication is strip on the matrix. Zircon and.alumina which are chosen as the friction components embed in the matrix.2. The density of samples decrease with increasing the graphite content. It may be related to the graphite increases the porosity of the material. With the same graphite content, the bigger the size graphite is, the less the particle number and the smaller the surface area, so the less pore between the graphite and matrix makes that the density of samples which the size of the graphite is300～600μm is higher than that of samples with the100～300μm graphite.3. The wear rate of two group samples with the different size increases with increasing speed. When the size of the graphite is300～600μm, the wear rate of the samples decrease with the increase of graphite content. This is due to the effect of the friction film which is formed by the bigger size graphite on the frictional surface. When the size of the graphite is100～300μm, the wear rate of samples increases with the increase of the graphite content. This is attributed to the smaller size graphite that has the bad effect on the strength of the materials, which results in reduction of the wear resistance of friction material.4. When the content of graphite is10%and the size of graphite is300～600μm, the sample has the best friction and wear properties.