Research On The Manufacturing Technique And Performance Of Self-lubricating Metal-based Materials

Because of the huge economic losses that came from the friction and wear, self-lubricating bearing technology became a trend in the future.The bearings materials that were prepared by embedding solid lubricating materials in the metal matrix achieved self-lubricating without lubricating or lubricating at a relatively long period and in the poor working conditions such as high temperature, low temperature, pollution, corrosion, fresh water or sea,vacuum, radiation,moreover it possessed unparalleled superiority that includes low friction coefficient, wear, extended life.Because solid lubricating materials effectively reduced the friction wear by way of the formation of transfer film between the solid lubricating materials and the friction piece, therefore,Successfully broke through the limitations of the traditional grease lubrication.Therefore the preparation technology and performance study of solid lubricating materials were of great significance.This paper made an intensive study on the relation between the sintern art of PTFE based self-lubricating composite and its mechanical properties and friction and wear properties.Besides comparative studies on friction and wear properties were made among brass ,tin bronze,nodular cast iron and 40Cr that were served as metal martrix.Graphite was chosen to modify the PTFE and established the four factors and three levels that had great influences on the the properties of PTFE composites:heating rate(60℃/h-180℃/h),holding temperature(260℃-320℃),sintering temperature(370℃-390℃),cooling method(furnace cooling,air cooling,water cooling).Then the experiments based on orthogonal experimental design was arranged. The results showd that:sintern art has limited influence on the PTFE composites; sintering temperature is the major fator for the hardness of PTFE composites;the wear loss is the major fator for the PTFE composites; heating rate is the major fator for the friction coefficient of PTFE composites.When determining the sintering process, synthetically considerating the desired performance and adjusting the different factors and levels to achieve the required process.And laying a foundation for the widespread use of the PTFE composites.Then adopting PTFE composites that are made by the first sintern art with better perfomence, brass,tin bronze, nodular cast iron and 40Cr were served as metal matrix respectively and friction wear performance of different metal matrix were compared. The results showd that:Under the low-speed and low-load working conditions, the coefficient of friction of four metal matrix were dramatically reduced compare with unembedded metal matrix after going into a stable friction state.After estimation and analysis,sample plate made by ductile iron as embedded matrix has the low coefficient of friction and better wear properties,the wear loss of the brass and tin bronze were larger.Moreover tight cohesion of transfer film between samples plate made by brass as embedded matrix was observed and the results of XRD phase analysis showd that:a little Fluoride ion metal compounds on the friction surface is beneficinal to the cohesion between the transfer film and the matrix.