Research Of Ni Foam/Polytef Composite And Tribological Behavior For Mechanical Sealing Surface

Marine mechanical seal is one of the major parts of the marine propulsion system. Mechanical seal research on domestic and overseas is mainly concentrated on the researches of sealing surface in failure analysis, the static thermal effects, where morphology and preparation process of sealing materials. As mutual friction mechanical part, no matter on which kinds of materials manufacturing sealing surface, friction and wear performance should be studied. Friction and wear performance research of the stationary ring can provide an important basis for the design, reduce the waste of manpower and resources, make designers earlier realize performance and structural requirements. This thesis according to the operation characteristics and strength requirements of marine mechanical seal designed and prepared a kind of seal face materials. Designed polymer matrix composites are the main object of study, the content is seal face stress analysis, composite material design and preparation process, mesh metal and particles fillers theoretical studies of the wear mechanism.1. On the basis of the sealing interface operating characteristics and failure causes, by the experiment determined the ratio of raw materials for prepared the sealing surface composite, the pre-processing of raw materials and molding process also made a thorough study. The high temperature pyrolysis process was determined, under the conditions of550℃nanotubes (CNTs) deposited on mesh material foamed nickel. After mixing diamond micro powder after3-4times procuring then raised the temperature to280℃for heat preservation two hours completely solidify molding, finally obtained nickel foam/PTFE composites-seal face material.2. Experiment tested the effects between different mass ratios of the foamed Ni/PTFE composite material; found that the mechanical properties of such composites are a direct ratio to the amount of nickel foam. Compared with the fibers or particulate filler, metal mesh which has a three-dimensional shape was not impacted by arrangement direction. It simply related to the content of the nickel foam for enhancing the mechanical properties. But when higher the content of nickel foam the coefficient of friction will also increase accordingly. The synergy effect between nickel foam and diamond micro powder fillers in mechanical friction performance will be weakened with increasing nickel foam filler content.3. Wear experiment records the wear rate of the material; scanning electron microscopy(SEM) analysis of the morphology; X-ray diffraction(XRD) qualitative wear product of the other couple, analysis focus on the wear properties and study on wear mechanisms and characteristics of the composite filter. Also research of deposition characteristics generated in sliding friction process.4. The creep performance of foam Nickel/PTFE composite was tested by compressive creep test mostly close to the actual mechanical seal interface operating. Using the compression creep test results substitution in commonly viscoelastic model for compared accuracy rate. Selection of the generalized Kelvin five parameters model and the Brugers model, calculated the creep parameters of the composite model respectively.5. Discussion on the marine mechanical seal operating characteristics, combined with basic and necessary assumption condition for simplifies the force on the end faces in sealing system. Finally, using the finite element method discussed contact characteristics in detail. The model is calculated by the actual mechanical seal structure; selected foam Nickel/PTFE composite material parameters used for the calculation of the simulation process analysis. The main content of the simulation is material contact stress in the operation process and strain distribution with the heat conduction rule.By researching proven mesh nickel foam can reinforce material effectively improve the mechanical and technological properties of the composites, especially the wear resistance. However, along with the broaden engineering friction and wear applications, in the field of polymer matrix composites, explore the mesh material (three-dimensional morphology) packing as well as the synthesis of functional filler composite material, friction characteristics, mechanism of failure modes and other issues needs further explored.