Electrolytic polishing
Michelle
www.xy-global.com
2018-08-23 19:20:57
Electrolytic polishingIt refers to the special anodizing treatment of metal products in a certain composition to obtain a smooth, bright surface finishing process. It can be used for surface preparation before plating, as well as for finishing after plating, and as an independent finishing method for metal surfaces.
The efficiency of electropolishing is higher than that of machining, and the surface after polishing produces a dense and firm oxide film, which does not produce a work-affected layer, has no residual stress, is not limited by materials, and is often used in production. Electropolishing has the following characteristics:
1) Small current, large gap.
2) Simple and fast.
3) The oxide film acts as a corrosion protection.
4) No work hardening and residual stress.
Influencing factor
1. Electrolyte composition
Depending on the polishing material, the composition and density of the electrolyte used are different, and the polishing parameters are also different.
2. Current density
The current density has a significant effect on the flattening speed of the metal surface and the amount of metal dissolved. If the processing time is the same, the surface leveling and the metal dissolution rate are faster when the current density is large, and the relative leveling ratio (the unevenness ratio before and after polishing) at the unevenness is independent of the current density at the same amount of electricity.
3. Metallographic structure and original surface
Electropolishing is very sensitive to the uniformity of the metallographic structure. The more uniform and fine the metallographic structure of the metal, the better the polishing effect. If the metal is present in the form of an alloy, the electrolyte in which the alloy composition can be uniformly dissolved should be selected.
4. Temperature and agitation
The temperature of the electrolyte has a great influence on the viscosity of the solution and the properties and composition of the anodic film. Generally, the higher the temperature, the faster the leveling speed. When the temperature is raised from 30 ° C to 70 ° C, the metal dissolution rate is almost increased by 1.5 times. When the current density is 0.5 A/cm 2 , the electropolishing time is 10 min, and the most suitable temperature is 100 ° C, but in order not to boil the solution, it is generally about 70 ° C.
The electrolyte should be stirred as much as possible during electropolishing, which not only promotes the flow of the electrolyte, but also ensures ion diffusion in the polishing zone and replenishment of the new electrolyte, and reduces the electrolysis temperature difference to ensure optimum polishing conditions.
The efficiency of electropolishing is higher than that of machining, and the surface after polishing produces a dense and firm oxide film, which does not produce a work-affected layer, has no residual stress, is not limited by materials, and is often used in production. Electropolishing has the following characteristics:
1) Small current, large gap.
2) Simple and fast.
3) The oxide film acts as a corrosion protection.
4) No work hardening and residual stress.
Influencing factor
1. Electrolyte composition
Depending on the polishing material, the composition and density of the electrolyte used are different, and the polishing parameters are also different.
2. Current density
The current density has a significant effect on the flattening speed of the metal surface and the amount of metal dissolved. If the processing time is the same, the surface leveling and the metal dissolution rate are faster when the current density is large, and the relative leveling ratio (the unevenness ratio before and after polishing) at the unevenness is independent of the current density at the same amount of electricity.
3. Metallographic structure and original surface
Electropolishing is very sensitive to the uniformity of the metallographic structure. The more uniform and fine the metallographic structure of the metal, the better the polishing effect. If the metal is present in the form of an alloy, the electrolyte in which the alloy composition can be uniformly dissolved should be selected.
4. Temperature and agitation
The temperature of the electrolyte has a great influence on the viscosity of the solution and the properties and composition of the anodic film. Generally, the higher the temperature, the faster the leveling speed. When the temperature is raised from 30 ° C to 70 ° C, the metal dissolution rate is almost increased by 1.5 times. When the current density is 0.5 A/cm 2 , the electropolishing time is 10 min, and the most suitable temperature is 100 ° C, but in order not to boil the solution, it is generally about 70 ° C.
The electrolyte should be stirred as much as possible during electropolishing, which not only promotes the flow of the electrolyte, but also ensures ion diffusion in the polishing zone and replenishment of the new electrolyte, and reduces the electrolysis temperature difference to ensure optimum polishing conditions.
application
Electropolishing can reduce the surface roughness value of parts, control the macroscopic unevenness of materials, increase the surface gloss and reduce the friction factor. Therefore, it can replace mechanical polishing in many occasions, which can greatly improve productivity and reduce materials, tools and equipment. Consumption of electricity, etc. Electropolishing is widely used in the processing of bearings, reflectors, cutting tools, measuring tools, bicycle parts, textile machinery parts and medical equipment.
Electrochemical polishing is mostly used in the laboratory to study the metal surface characteristics of certain materials, such as optical properties, magnetic properties, electrochemical properties, diffraction properties of electrodes, corrosion and friction properties.
Electrochemical polishing is mostly used in the laboratory to study the metal surface characteristics of certain materials, such as optical properties, magnetic properties, electrochemical properties, diffraction properties of electrodes, corrosion and friction properties.
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