Preparation Of Iron-based Self-lubricating Coatings By Laser Cladding

Solid lubricants were first applied to the military industry,and later in some high-tech fields such as artificial satellites,spacecraft,and high-tech electronic products.However,each solid lubricant has a specific lubrication environment.So far,no solid lubricant has been found to have a wide range of operating temperatures alone.Therefore,various solid lubricants can be used to produce composite solid lubricants to solve the problem of wide temperature lubrication.In this paper,using laser cladding technology,Fe400-based h-BN/CaF₂ dual-phase self-lubricating coating was prepared on the surface of 45#steel by a semiconductor laser with a preset powder coating method,Then their microstructure,microhardness,and resistance,tensile strength,impact toughness,as well as friction and wear properties were studied.Through theoretical studied,the characteristics of solid lubricants and the general laws of laser cladding were studied,laying the foundation for the subsequent e xperiments.The macroscopic morphology under different laser powers and scanning speeds was studied,and a 300mm/min scanning speed and laser processing power of 2500W were tested.The coating with the added solid lubricant had a finer structure as a whole than the coating without the solid lubricant.The tensile property became better.The tensile strength increased.The impact toughness deteriorated overall,and the friction performance increased.Considering comprehensively,when the mass ratio of Fe-based powder,h-BN to CaF₂ was 98:1:1,although the impact toughness was lower than that of pure Fe400.It was the best among those which were added solid lubricants.This ratio of self-lubricating coating had the best quality and performance for all concerned.The results of laser cladding of the dual-phase self-lubricating coatings from both theoretical and experimental results showed that adding 2%of solid lubricant to the Fe400alloy powder.When the ratio of h-BN and CaF₂ is 1:1,the quality and performance of the cladding layer could be effectively increased,which layed the foundation for the study of lubrication in a wide temperature range.