What are the requirements for the electrolyte in electrolytic grinding?

       Electrolyte is an extremely important factor affecting productivity and machining quality in the electrolytic grinding process because it directly affects the electrochemical reaction of the anode. According to the electrochemical reaction theory, electrolytes with different compositions have different anodic reaction speeds and different degrees of chemical dissolution of their reaction products. The electrolytic grinding process requires not only oxidation but also passivation. In order to obtain high productivity and good surface quality, an aqueous solution with sodium nitrite or disodium hydrogen phosphate as the main component is generally used (the pH value is 8~9). Another important requirement for the electrolyte is that it does not corrode the machine tool and endanger the human body.



     The selection of electrolyte should consider the following five requirements:

    (1) A passivation film with tight structure and strong adhesion can be formed on the metal surface to obtain good dimensional accuracy and surface roughness;

    (2) Good electrical conductivity to obtain high productivity;

    (3) Non-corrosive machine tools and fixtures;

    (4) No harm to human body to ensure personal health;

    (5) The economic effect is good, the price is cheap, the source is abundant, and it is not easy to be consumed in processing.

     It is difficult to meet the requirements of the above five aspects at the same time. In actual production, the best electrolyte for electrolytic grinding should be selected according to the technical requirements and materials of different products.

     The test shows that the electrolytic grinding of high-hardness thermal spray coating, the electrolyte with disodium hydrogen phosphate as the main component, has better grinding performance. The electrolyte with disodium hydrogen phosphate as the main component has good results in terms of processing efficiency, processing accuracy and surface quality. The high processing efficiency of this electrolyte is mainly because in addition to the electrical conductivity and oxidation of sodium nitrite and potassium nitrate, disodium hydrogen phosphate is ionized in an aqueous solution, making the solution weakly alkaline (pH=8~9), It is beneficial to the dissolution of oxides and accelerates the electrolysis process, thereby obtaining large current efficiency and improving processing efficiency.