Study Of Ca-P Coatings Prepared By Supersonic Atmospheric Plasma Spraying Combining Microwave-Hydrothermal Method

It is a hot spot of interest for a long time how to improve the mechanical properties between the hydroxyapatite?HA?coating prepared by supersonic atmospheric plasma spraying?SAPS?,and carbon/carbon?C/C?substrate,and the decomposition,amorphous phase,surface defects,especially in biomedical fields such as bone regeneration and bone conduction.In this study,microwave-hydrothermal?MH?method which could prepare Ca-P inner coating and changed the surface roughness of C/C substrate was used to enhance the mechanical properties between the C/C substrate and HA coating;Besides,the HA coating was treated by MH method to uniform the decomposition and heal the surface defect.Then,the morphologies,phase composition,functional groups and elements were measured by SEM,XRD,FTIR,EDS to detect the mechanism for the mechanical properties,bioactivity and corrosion resistance.The primary coverage are as follows;?1?Optimized by orthogonal experimental design,parameter selection of excellent HA coatings prepared by SAPS process,which is mainly based on the bonding strength of HA coating and C/C substrate,coating thickness,coating composition,the results showed that appropriate SAPS patameters for spraying;42 kw,4.2 r/min and 15 times.In addition,the influence of surface porosity and roughness of different C/C substrate surface on the bonding strength between the HA coating and substrate was studied.Among them,the bonding strength between C/C substarte and HA coating is the highest?13.25 MPa?with the roughness of 16.56?m.?2?The Ca-P inner coating is prapred by on the surface of C/C substrate by MH process,which makes the surface roughness of C/C substrate larger.The effects of surface modified C/C substrate on the mechanical properties of HA coatings prepared by SAPS are systematically investigated.Compared with the mechanical properties of C/C coating without MH pretreatment,the mechanical properties of C/C substarte prepared by MH treatment with different Ca²⁺concentrations?10 mmol/L,500 mmol/L and 1000 mmol/L?and reaction temperatures?120°C,150°C and 180°C?of HA coating increased by 160.76%,70.70%,37.58%,38.22%,63.18%and 88.54%,respectively.This is due to the uneven surface of coarse-grained C/C substrate,reducing the direction of partial contraction force during the coating preparation,reducing cracks,and improving the riveting point between the fused HA powder and C/C substrate,thereby effectively improving the mechanical properties between the substrate and the coating.?3?MH treatment of HA coating sprayed by SAPS method,explores the different MH process parameters(precursor solution of Ca²⁺ionic concentration,microwave heating temperature and time)influence on microstructure of coating surface morphology evolution,phase composition and biological activity in vitro reaction and corrosion resistance.The surface phase and defects of HA coating treated by MH method are well improved and the Ca-P composite coating exhibits well activity reaction in vitro and excellent corrosion resistance.