Study On Microstructure And Properties Of Electrolytic Nickel

Nickel is widely used in smelting alloys,electroplating,batteries,aerospace and so on.The production technology of nickel in China is basically mature,but the quality of electrolytic nickel needs to be improved.In this paper,the tensile strength,impact strength and influence law of electrolytic nickel plate at different deposition time were studied by room temperature tension and room temperature impact.The microstructure of electrolytic nickel plate at different deposition time was studied by X ray diffraction and scanning electron microscope,and the preferred orientation of the electrocrystallography was also studied.The grain size and the surface morphology of the electrolytic nickel were compared and analyzed.The results of the study are as follows:With the increase of deposition time,the surface brightness of the electrolytic nickel decreases and the thickness of the deposit layer becomes uneven.Electrolytic nickel board is stable in chemical composition,but sulfur content is slightly higher,but it is in line with national(industry)standard requirements.The strength of the beginning plate is higher.The tensile strength of nickel plate with nickel deposition of 48 h has reached a higher value.Then the tensile strength decreases with the in crease of deposition time and changes in a certain range,but the fluctuation is not significant.The tensile strength of the electrolytic nickel plate at the upper,middle and lower parts of the electrolytic nickel plate varies slightly at different time of deposition,and the tensile strength of different electrolytic nickel plates is slightly higher than the tensile strength in the horizontal direction.The fracture of the tensile specimen is a "cup cone" of ductile fracture.The fracture of the fracture is composed of two parts of the dimple and edge of the internal size,like the "wavy" shape,and the middle beginning plate is obviously separated from the nickel deposit.The impact test specimen has good toughness and is suitable for processing and shap ing nickel products.The upper and middle positions of the starting sheet are(111)and(200)diffraction peaks of the crystal surface.(200)the intensity of the diffraction peak is higher,and the lower part is(111),(200)and(220)diffraction peak.The deposition time increased,and the electrolytic nickel plates deposited 24 h and 48 h showed(111)and(200)diffraction peaks.From the beginning of deposition time 72 h,the upper and lower parts of the 96 h and 120 h electrolysis nickel plates show th e diffraction peaks of(111),(200)and(220)planes.The electrolysis nickel deposited at 168 h,192 h and 216 h showed strong(200)diffraction peaks and weak(111)diffraction peaks.The grain size of nickel deposited layer is about 60 nm,and it belongs to nanometer level.It has little difference from the grain size of high quality electrolytic nickel produced abroad.The surface of nickel deposited layer at the beginning and the different depo sition time is not obvious at low grain boundaries,indicat ing that the microstructure of electrolytic nickel is compact.The surface of the starting plate is mainly composed of small "pyramid" structures with a homogeneous distribution.With the increase of deposition time,the "lamellar" structure increases and the agglomeration size becomes larger and interlaced with different preferred texture.As the deposition time increases,the microstructure of the deposit section is mainly from the equiaxed crystal near the starter sheet,and gradually changes to the thic k columnar crystal near the surface of the deposit.The brightness of the nickel deposit increased with the addition of different additives.When the content of the mixed additive is high,the luminance of the nickel deposition layer increases obviously,a nd the presence of the mixed additive in the electrolyte can inhibit(220)the preferred growth of the crystal surface,and make the nickel deposition layer(111)and(200)the bidirectional texture.The micro morphology of nickel electrodeposited layer is fine and homogeneous cellular structure.The grain size of nickel deposit is obviously refined and the size is about 20~30 nm.