Preparation And Properties Of Ni - P - Nano - SiO 2 Composite Composite Coatings

In the 21st century, the performance of nanoparticles has been further studyed, with the rapid development of industry and materials increasingly updating. Using composite plating method can effectively reflect the nature of the nano-coating, so that the hardness is greatly increased, resistance corrosion and wear resistance are greatly improved, but also further enhance the bonding strength, which plays a good performance on the important practical significance.This article was prepared composite coatings two methods to study the properties of the composite coatings. In a dispersed aqueous medium, nanometer silicon particles were dispersed using a variety of physical and chemical dispersion method which makes nanoparticles dispersed in a chemical bath environment. Then compare a variety of dispersion methods and their complexes, find chemical composite coating liquid pH value and temperatures better in a decentralized manner. It was applied to Ni-P-(nano) SiO2 composite plating while using homemade sol-gel method to make composite plating. Then Use SEM, micro-hardness, corrosion potential analyzer and static immersion method to analyze composite coatings on the surface morpHology, structure, hardness and corrosion resistance and compare with Ni-P coating performance. We can have conclusions:First, use mechanical stirring and ultrasonic dispersing them in a decentralized manner, while select Tween-80, cetyl trimethyl ammonium bromide CTAB, Tetramethylammonium hydroxide TMAH, sodium dodecyl benzene sulfonate LAS, sodium pyropHospHate TSPP dispersant. Make different kinds and amounts for the first single-factor test and orthogonal experiment in order to study dispersion and stability, and get the optimal level in alkaline bath environment during dispersion process. To obtain the optimum combination:750r/min continuous mechanical stirring 20min,600W continuous ultrasound 7min, Tween-80 volume 0.2%, TSSP 0.2mg. At this point nano-powders are well dispersed, and no obvious reunion.Second, The optimal combination of nano-dispersion of the nanoparticles is used in the composite plating method. Using coating the surface morphology, elemental composition and hardness values were analyzed. It can be concluded:nanoparticles coated in a chemical compound coating, but some larger particles dispersion is not uniform. There is little agglomeration, the hardness value increases slightly which iscompared with the chemical coating. Overall, the nanoparticles prepared by chemical composite coating make a success, but the effect is less than ideal.Third, in the composite coating sol-gel method, the nanoparticles are dispersed in the interior and surface coatings, Ni-P-SiO2 nanocomposite microhardness ratio are improved which is compared to Ni-P coating. Ni-P-(nano) SiO2 coating adhesion is stronger than Ni-P alloy coating, and exhibits better wear resistance. By corrosion potential instrument and at room temperature for 10% H2SO4 and 15% HCl solution standard corrosion, test samples and conducting chemical composite coating in 12 hours static immersion method. Compared to Ni-P alloy coating, corrosion resistance can be enhanced, much higher than the base steel. Meanwhile make polarization curves of electroless composite coating and Ni-P alloy coatings. Chemical composite coatings in 3.5% NaCl solution compared to Ni-P alloy coating, corrosion resistance has been improved.