Principles And Characteristics Of Chemical Polishing

Chemical polishing is a method of eliminating abrasion marks and leaching and levelling by the selective dissolution of chemical reagents on the uneven areas of the sample surface. It is a method of chemical treatment for improving the surface finish of metal parts by immersing them in an acidic or alkaline solution. Chemical polishing can rely on the spontaneous chemical reaction of the chemical polishing solution, without the use of electricity and human conditions, automatically to polish the workpiece to improve the surface finish, can achieve a mirror effect. We can also simply understand: chemical polishing is the use of chemical potions to brighten things up.

Principle of chemical polishing

The principle of chemical polishing is that metal surfaces are bright and smooth through regular dissolution. In the chemical polishing material, polishing wax (4 sheets) light process, the surface of steel parts constantly formed passivated oxide film and oxide film dissolution, and the former is stronger than the latter. Due to the microscopic inconsistency of the parts surface, the surface microscopic raised parts priority dissolution, and the dissolution rate is greater than the dissolution rate of the concave parts; and the dissolution of the film and the formation of the film is always carried out at the same time, only its rate difference, the result of the steel parts surface roughness can be leveled, so as to obtain a smooth and shiny surface. Polishing can fill surface pores, scratches and other surface defects, thus improving fatigue resistance, corrosion resistance. The different electrochemical potentials of the constituent phases on the surface of the metal specimen form a number of micro-potentials that produce uneven dissolution in the chemical solution. In the dissolution process the surface layer of the specimen surface will produce a layer of oxide film, the specimen surface projection part due to the thin mucous film, the dissolution of metal expansion is slow, polished surface smooth, but the formation of a small undulating waveform, can not reach the very ideal requirements. When observed with a microscope at low and medium magnification, this small undulation is generally within the vertical discrimination capability of the objective, and a very clear tissue can still be observed

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According to the different physical and chemical properties of the workpiece material, the corresponding metal chemical polishing fluid types are not consistent. There are mainly the following categories.

1. Stainless steel chemical polishing solution: suitable for stainless steel surface polishing, deburring, deburring, weld spot, removing oxidation skin and other processing, can reach the mirror effect. The solution is environmentally friendly, no pungent smell, in line with food-grade environmental requirements.

2. Chemical polishing solution for copper and its alloys: suitable for all copper and copper alloys to remove rust, remove oxidation skin, remove copper green and other surface polishing treatment. Make copper parts to achieve bright as new effect. High polishing efficiency, low cost, no need for special equipment, just soak in a rubber frame. The liquid is environmentally friendly, no yellow smoke and acid mist. Meet the requirements of food-grade environmental protection.

3. Chemical polishing solution for aluminium and its alloys: suitable for polishing out brightness of all aluminium and aluminium alloy materials (excluding aluminium castings). No yellow smoke, no harmful materials, environmental protection, in line with SGS requirements. Easy to use, no heating required. The chemical aluminium polishing solution can quickly improve the gloss of aluminium, achieve a mirror finish and remove burrs.