Alumina plate chemical polishing defects and countermeasures

[China Aluminum Network] The defects in the chemical polishing of anodized alumina plates and their corrective measures are continuously summarized during the development of production.

Insufficient brightness This is a concern in chemical polishing. The brightness does not reach the desired target, and the reason can be analyzed from the production process of special aluminum materials and the chemical polishing process. The production process of special aluminum materials has been discussed in detail. Aluminum ingots with an aluminum purity of 99.70% or higher are recommended to produce special aluminum materials; quality control in aluminum processing lays the foundation for chemical polishing to obtain a high-luminosity surface. After chemical polishing, it has a high brightness. If the content of nitric acid in the bath control is insufficient, the surface brightness will be insufficient, and a layer of copper may be excessively attached to the surface. If the content of nitric acid is too high, an iridescent film will be formed on the surface of the aluminum material, which will make the surface fuzzy or opaque, and cause insufficient brightness; The chemical polishing time is insufficient, the temperature is not enough, the stirring is not sufficient, and the aging of the bath solution also causes the chemical polishing surface to have insufficient brightness. The relative density of the bath liquid is relatively large, preventing the aluminum material from floating out of the liquid surface of the polishing bath fluid, resulting in insufficient brightness of the upper aluminum material. The effects of water cause insufficient brightness and are often easily overlooked. It is better to use dry aluminum to enter the chemical polishing bath to prevent the water from being introduced.

White Attachment The appearance of the defect is that a layer of white deposit adheres to the surface of the chemically polished aluminum material, and the distribution is not uniform, and the surface of the aluminum material at the bottom of the attachment may be corroded. Usually, this defect is caused by the too high amount of aluminum dissolved in the chemical polishing bath. If the relative density of the chemical polishing bath is above 1.80, it can be further confirmed. It is necessary to take measures to adjust the amount of dissolved aluminum in bath solution to the normal range.