Preparation method of Co-Ni alloy electroplating solution

Abstract

The invention provides a preparation method of a Co-Ni alloy electroplating solution, wherein the electroplating solution can effectively inhibit abnormal deposition of CoNi, an obtained plating layeris small in grain, smooth in surface, low in internal stress and high in deep plating capacity, and electroplating effect is superior to that of similar plating solutions.

Description

technical field [0001] The invention belongs to an electroplating process, and relates to a method for preparing a Co-Ni alloy electroplating solution for a porous copper plate used in a crystallizer. Background technique [0002] Continuous casting is the most important method of producing steel slabs, and the mold is compared to the "heart" of the continuous casting machine. The performance of the mold copper plate directly affects the quality of the casting slab, the production efficiency and production cost of continuous casting, crystallization As an important heat-conducting part of molten steel solidification and forming in continuous casting, the copper plate of the mold is to release the heat of the liquid steel as soon as possible to form a solidified billet shell of sufficient thickness. Therefore, for the copper plate of the mold, its primary function The functional requirement is better thermal conductivity, which is why copper is selected as the mold material. ...

AI Technical Summary

Problems solved by technology

[0004] Single-plated Cr layer, advantages: high hardness, good chemical stability; disadvantages: there are cracks regardless of thickness, the expansion coefficient and thermal conductivity are greatly different from the copper substrate, and it is easy to fall off. At present, it has been abandoned.

Advantages: Ni acts as an intermediate transition to improve the bonding strength. The outer surface is a Cr layer, which has good wear resistance and can eliminate reticular cracks on the surface of the slab; disadvantages: the plating process is complicated, and the thermal expansion coefficient and thermal conductivity of Cr and Ni There is a large difference in the rate, the bonding strength between the Cr layer and the Ni layer is low, the electroplating process of the nickel plus chromium coating is complicated, and the nickel layer is mainly used for wear resistance, so the service life of the coating is still limited, and the thin and porous chromium coating can be used at high temperatures. In addition to being not resistant to corrosion in corrosive environments, galvanic corrosion is easily generated between the nickel plating and the chromium plating (currently most copper plates in continuous casting crystallizers are double-coated with Ni plating on the inner layer and Cr plating on the outer layer)

Disadvantages: Poor potential corrosion resistance and thermal alternation resistance, difficult control of alloy plating solution, low yield rate, iron content in nickel-iron alloy used as slab crystallizer coating is generally controlled at 3% to 12%, and its hardness is at room temperature. 320 ~ 420HV, the wear resistance is enhanced, but compared with the nickel layer, the disadvantage of the nickel-iron alloy is that the chemical stability is reduced, especially under high temperature conditions, hot corrosion or ablation rapidly expands and cracks are prone to occur; and the brittleness increases and high The internal stress, and the bonding strength with the base metal is also affected, so the nickel-iron coating has poor thermal alternating resistance

[0011] It can be clearly seen from the above results that the direction of improving the coating in the prior art is mainly focused on the adjustment and improvement of the coating composition and parameters, or the use of composite plating to improve the coating effect through inorganic particles, but in the prior art, there are few copper plates and coatings. The plating solution starts at the same time, and improves the bonding force between the copper plate and the plating layer by improving the state of the copper plate surface

Images