The Key Technology Research And Applications Of WC Abrasion Resistant Coatings Sprayed By Supersonic Flame Spraying

The abrasion failure is one of the key issue in hydraulic machinery development.Scholars and engineers all over the world have carried on the research to it,and obtained some progress.Generally,through the structural optimization designing,anti-wear base metal choosing,non-metal organic coatings and epoxy composite coatings,surfacing to improve the anti-corrosion performance of hydraulic machinery.In this topics,the nano-scale feedstuffs were successfully fabricated by liquid-phase spraying that can be used for the high velocity oxy fuel spraying.Nano and micro structure WC10Co4Cr coatings were prepared by high velocity oxy fuel?HVOF?.And 16 kinds of WC10Co4Cr metal ceramic coatings were prepared by orthogonal test.By Optical microscope?OM?,X-ray diffraction?XRD?,electron spectroscopy?EDS?,scanning electron microscopy?SEM?,scanning electron microscopy?SEM?,The microstructures and properties of the Nano and micro coatings were researched,and the properties and properties of the coatings were summarized.The microhardness,wear resistance and bonding strength of the coatings were studied by microhardness test,wear test,abrasion test and bonding strength test,and optimized the spraying process.It is successful implicated in anti wear plate of hydro turbine,which improve the abrasion resistance of hydraulic turbine effectively.The main work and results of this project are as follows:?1?For the seriously abrasion of hydraulic machinery,A project proposed nano coating to enhance parts wear and corrosion resistance.And the high anti abrasion nano WC10Co4Cr coatings was manufactured successfully,which has achieved stage success.?2?Through the liquid spraying granulation technology,HVOF nano feeding has been manufactured successful.The main process of spray granulation and the ideal process parameters as follow:Technique:Dispersed nano powder?Preparation of slurry?Spray drying?Sinter?filterTemperature of Drying oven:160?;Sinter Temperature:1100?;Sinter times:4h??3?The nanostructure WC10Co4Cr coatings are more compact than the micron structure coatings which are all manufactured by HVOF.Microhardness and abrasion of nanostructure WC10Co4Cr coatings are better than micron structure coatings.?4?The nanostructure WC10Co4Cr coating sprayed by HVOF is Melted more adequately.The powder is flattered high in Accumulation process.Oxidation and decarburization of The nanostructure WC10Co4Cr coating is worse than the micron structure coatings.A few W₂C is existed in coatings because of Oxidation and decarburization,but no Brittle free carbon in them.?5?The erosion mechanism of the micro-coating is mainly on the cutting and fatigue flaking in Sediment flow.In nanostructure WC10Co4Cr coating,the coating particle size is fine,Most grain boundaries are fine grain boundaries,the number of inter-particle binding surfaces increased,Nano-grain distributed uniformity,which played a very good"pinning role"for bonded phase,improved the micro hardness and toughness of the coating.High hardness enhanced the resistance to micro-cutting and plowing.?6?To optimize the process parameters by orthogonal experiment,kerosene flow,oxygen flow,Powder delivery,distance were Four-level factor.The main factor affecting the anti-wear performance of the coating is kerosene flow.In this topics,the best HVOF parameters were:kerosene flow 28L/h,oxygen flow 50m3/h,Powder delivery 60g/min,distance 340mm.