Beryllium bronze oxidation film cleaning agent and preparation method thereof

Abstract

The invention relates to a beryllium bronze oxidation film cleaning agent and a preparation method thereof, belonging to the technical field of metal surface chemical treatment. The beryllium bronze oxidation film cleaning agent comprises the following components in terms of weight percent: 20-50% of sulfuric acid, 2-20% of nitrate ions, 2-10% of organic phosphonic acid, 0.01-1% of halogen ions and the balance of water. The preparation method is as follows: (1) preparing the components according to the weight percents; and (2) slowly adding the sulfuric acid into the organic phosphonic acid with the formula amount, fully stirring the mixture, cooling the mixture to the room temperature, then adding nitric acid, fully stirring the mixture, adding the halogen ions, and finally obtaining theberyllium bronze oxidation film cleaning agent. The beryllium bronze oxidation film cleaning agent adopts the complex system of the organic phosphonic acid, the sulfuric acid, the nitrate ions and thehalogen ions to solve the problem of difficult beryllium bronze oxidation film removal and to simultaneously replace a conventional hexavalent chromium pickling system; and the beryllium bronze oxidation film cleaning agent reduces the pollution and improves the pickling effect. After cleaned by the cleaning agent, a beryllium bronze surface is flat and bright, therefore the performance and the appearance of a beryllium bronze product are improved.

Description

technical field [0001] The invention belongs to the technical field of metal surface chemical treatment, and in particular relates to a beryllium bronze oxide film cleaning agent and a preparation method thereof. Background technique [0002] Beryllium bronze not only has high strength and high hardness after heat treatment, but also has the advantages of wear resistance and corrosion resistance. It is widely used in the manufacture of various molds, explosion-proof safety tools, wear-resistant parts such as cams, gears, worm wheels, bearings, etc.; High conductivity cast beryllium copper alloy has high electrical conductivity and thermal conductivity after heat treatment, suitable for manufacturing switch parts, strong contact and similar current-carrying components, making clamps for resistance welding, electrode materials and plastic molds, water and electricity connections Casting machine crystallizer inner sleeve, etc. [0003] The processing of beryllium bronze includ...

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Problems solved by technology

[0004] Due to the very dense oxide film produced during the processing of beryllium bronze and the excellent corrosion resistance of beryllium bronze itself, it is difficult to remove the oxide film by ordinary pickling. Even if sulfuric acid and nitric acid are used, it is still difficult to obtain satisfactory results. If the pickling time is too long or the concentration of oxidizing acids such as nitric acid is too high, it will cause over-corrosion or pitting corrosion on the surface of beryllium bronze, which will seriously affect the performance of beryllium bronze. At the same time, if the concentration of nitric acid is too high, yellow smoke will be produced, which will endanger workers health and environmental hazards

Most of the traditional beryllium bronze cleaning agents use sulfuric acid compounded hexavalent chromium salt (such as potassium dichromate, sodium dichromate) for immersion pickling, and then use sulfuric acid compounded chromic anhydride and phosphoric acid for bright pickling. The surface appearance of beryllium bronze products on the market does not achieve the desired effect. At the same time, hexavalent chromium is a serious pollutant, which is harmful to the environment and brings difficulties to wastewater treatment.

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