FC-T Lead-Tin Alloy High-Density-Rolling Anode Technology

First generation: Traditional electroplating chromium anode manufacturing has been using various metals such as lead antimony or lead tin antimony for casting for many years. The microstructure inside is loose, which is prone to defects such as cold shuts, casting nodules, shrinkage holes, and oxide inclusions, resulting in greater resistance during the movement of ions in production, thereby reducing the quality of the coating. However, the generation of high resistance not only leads to a decrease in production quality, but also generates high heat, resulting in an increase in electricity costs. As is well known, the looseness of the structure and the entry of impurities can lead to the violent erosion of weak areas by chromic acid, so the corrosion resistance of the cast anode is very low. Due to the low melting point of lead metal or lead tin metal, the lead tin alloy will gradually separate from the copper hook on the anode under the action of thermal energy, ultimately leading to the scrapping of the anode. So the service life of ordinary lead plates is generally about one year.

Second generation: Based on the casting manufacturing process, rolling manufacturing technology is used to achieve a certain level of surface smoothness. However, the structure inside the surface cannot be changed, causing the plating solution to penetrate into the interior and cause corrosion after consuming the surface. Generally, this can increase the service life by about six months

Third generation: After summarizing years of experience, we use high-density extrusion molding technology (1000 ton extruder extrusion) for chrome plated anodes. By using high-quality lead tin raw materials (purity ≥ 99.9%), adjusting the proportion of lead tin content (tin content 3-10%, antimony content 2-5%,&silver content 0.5-1%&), optimizing the structure of the anode, and using high pressure extrusion molding technology, the density of the metallographic structure has been greatly improved and the conductivity has been greatly enhanced, thereby reducing metal pollution to the plating solution, improving the dispersion ability of the plating solution, and reducing impurities in the plating solution, The surface quality of the chrome plating layer has been significantly improved. We have also optimized the shape of the hook, maximizing the contact area between the hook and the conductive rod (conductive strip), reducing resistance, and thus improving conductivity efficiency. This greatly improves the anode’s lifespan and conductivity, with a service life of 3 years or even more than 5 years for products with high tin content. The conductivity has generally increased by about 30%

The reasonable use of lead tin antimony alloy extrusion formed chromium plating anode in chromium plating can achieve a service life of 3-5 years or even longer, saving about 30% of electricity, and making fundamental improvements in environmental protection

Operations and Maintainance of Anode

The new anode is better put in the plating bath with electricity, there will be soon produced a dark brown layer on the surface named PbO:L5J, which is a kind of mormal covering layer, it can conduct current, and protect the surface from producing a yellow layer named lead chromate film, when the surface is eroded by chromate (PbCrO), which could cause voltage go higher, even non-conductive, the results in severe quality problems of products. Therefore, when product is finished, the anode has to be put out in time, and be washed clean and soaked in clear water bath.

Basic knowledge of Chrome Plating Anode

The quality of chrome plating is largely influenced by the following factors: shape & size, distribution of cathode and anode, the distance between them, and the shape of platin bath. These factors are related to plating solution distribution during production. It directly affects the distribution of power lines on the cathode surface, which decides whether the current distributes  evenly on product surface.One of the effective way to improve distribution is to increase the distance between cathode and anode, or decrease the difference between the distance of every part of cathode and anode. As increasing the distance between cathode and anode is limited to the shapes and sizes of plating bath, we mainly apply the latter way. During plating, we have to choose the proper shape and assemble the place of anode according to shape and size of product. The anode shape is largedly related to plating liquid with lower ability distribution and coverage. The principle of creating anode is pattern shape, which means the anode shape is basically as same as the surface of products. For most part of roller shaft products, anode should be shape cylindrical, place around cathode， working parts, current conducts from both sides, so power line distributes evenly, it’s better to avoid using flat shape anode. Besides, make sure there is enough current conducting area for the conjuction of anode, anode hook and anode bar. Or the power could be consumed soonly and produces lots of heat, which would cause the plating solution temperature go higher.