Preparation Technology And Properties Of Electroless Full-bright Ni-P-BN(h) Composite Coatings

In recent years,the use of electroless plating technology has improved and beautified people's lives,and has played an irreplaceable role in protecting and optimizing the environment.The use of nanomaterials to modify the coating in electroless plating not only ensures the comprehensive performance of structural materials,improves the application performance of corresponding functional materials and components,but also prolongs the service life of materials and their applied devices.Cubic boron nitride nanoparticles(h-BN)have been widely used due to their easy sliding,good self-lubricating effect and stability,and are a multifunctional material.The electroless plating technology was developed and applied in combination with boron nitride nanoparticles to prepare Ni-P-BN(h)self-lubricating coatings to improve the wear resistance and corrosion resistance of nickel-phosphorus alloy coatings.This paper starts from the influence of the growth conditions of the electroless Ni-P-BN(h)composite coating,takes low carbon steel as the substrate,studies the reasons that affect the quality and performance of the coating,and uses various characterization methods to analyze the experimental results.Find the best process parameters.The experimental content and results are as follows:(1)The effect of BN(h)particle concentration on Ni-P-BN(h)composite coating was explored,and purification experiments,surfactant selection experiments and BN(h)concentration comparison experiments were carried out respectively.In the purification experiment,the mechanical properties and electrochemical properties before and after purification were compared,and it was proved that the mechanical properties and electrochemical properties of the Ni-P-BN(h)composite coatings prepared from the purified BN(h)particles were improved.Therefore,purified BN(h)particles were selected for experiments.The surfactant finally selected the cationic activator octadecyl trimethyl ammonium bromide(STAB)with the strongest compatibility with the plating solution.The optimal concentration is 0.04 g/L.In the BN(h)concentration comparison test,seven concentrations of 0,5,10,15,20,25,and 30 g/L were set to compare their surface morphology,mechanical properties,and electrochemistry.When it is larger than 10 g/L,the agglomeration of BN(h)particles is aggravated,which leads to particle sedimentation,which is unfavorable for the formation of chemical composite coating.(2)The effects of temperature and stirring speed on the Ni-P-BN(h)composite coating were explored,and seven gradient stirring speeds of 100,200,250,300,350,400,and 500 r/min were set up from the actual pictures.To determine the optimal stirring speed is 200-300 r/min.Then,through the characterization of mechanical properties and electrochemical properties,it was further determined that the optimal stirring speed was200 r/min.The experimental results at different temperatures show that the Ni-P-BN(h)composite coating achieves the best mechanical properties at 86 ?,with a hardness of643.97 HV and a friction coefficient of 0.49.At this time,the corrosion potential of the Ni-P-BN(h)composite coating reaches a maximum value of-0.33 V,showing the best corrosion resistance.Therefore,considering the overall consideration,the optimal plating temperature for the growth of the plating layer is finally determined to be 86 ?.(3)The effect of pH value and deposition times on Ni-P-BN(h)composite coating was explored.The acidity of the plating solution decreases with each deposition.Therefore,for experimental accuracy,the plating solution should not be reused or added after each plating.Replenish the plating solution.It can be seen from the experimental results of different pH values that the Ni-P-BN(h)composite coating achieves the best mechanical properties when the pH value is equal to 4.7,the microhardness is 651.69 HV,and the friction coefficient is 0.4867.In addition,the Ni-P-BN(h)composite coating has the largest polarization resistance and a maximum corrosion potential of-0.33 V,showing the best corrosion resistance and corrosion resistance.The optimal pH for plating growth was finally determined to be 4.7.