1.Product use:
Piston rod, linear optical shaft, guide rod, guide rod
(Used as a component in cylinders, cylinders, shock absorbers, textile printing, printing presses, presses
Casting machine, injection molding machine, four-column press and other equipment components)
2.Manufacturing process:
Fine cold drawing, quenching and tempering, fine grinding, pulse chrome plating, high precision polishing, etc
3.Process characteristics
The process and the obtained hard chromium coating have the following characteristics:
(1)retain all the excellent characteristics of ordinary hard chromium coating, appearance grade 10, hardness 900HV
Above.
(2) high corrosion resistance, in the coating thickness of 30um neutral salt spray test can easily exceed 500 hours,
Far more than the maximum 200 hours of ordinary hard chromium. Wide application prospects, can meet the Marine, aviation
Corrosion resistance requirements in extremely demanding working environments such as aerospace and chemical industry.
(3) Multi-layer nanostructure hard chromium coating is formed once, and there is no need to stop and replace plating during plating
The groove can completely replace ordinary hard chromium, double hard chromium, three hard chromium and nickel chromium and other multi-layer plating
The process greatly reduces the process flow and reduces the equipment investment.
(4)the current efficiency can reach 27%, more than double the current efficiency of ordinary chromium plating, deposition speed
The degree is fast, up to 60μm/H or more, and the energy consumption is 1/3 of that of ordinary hard chromium plating.
4.Why choose us?
(1)Under the existing protective and decorative coating system, hard chromium coating (thickness 30 um~50μm), because of its inherent high hardness (between 600~1000HV), low friction coefficient (< 0.2, especially dry friction coefficient, It is the lowest in all metals), better heat resistance and good chemical stability, and is widely used in transmission, wear-resistant, scour resistant components, industrial and military fields.
It occupies an important position in the whole electroplating industry. However, the corrosion resistance of hard chromium coating has been poor, even nickel-chromium plating can only reach about 200 hours of neutral salt spray test, far from meeting the needs of high corrosion resistance occasions such as offshore drilling platforms and pesticide spraying machinery. At the same time, the electroplating process of hard chromium coating still has low current efficiency. The multi-layer electroplating system has many disadvantages, such as many equipment, complicated process, high cost of production and process maintenance.
(2)At present, in order to improve the corrosion resistance of the chromium plating layer, the existing technology has two main schemes: one is the multi-layer chromium process, the use of staggered layers to make up for each other's coating defects to improve the corrosion resistance, however, due to the existence of penetration cracks, even the three-layer chromium corrosion resistance is only to achieve neutral salt spray 96~ 192H. The second is to add a layer or several layers of anode coating between the chromium plating layer and the iron substrate, so that when the corrosion occurs, the anode coating is sacrificed first to delay the corrosion of the iron substrate, such as the current most common nickel and chromium multi-layer process is to use this scheme, in which the corrosion resistance of double nickel and chromium is only barely reached the neutral salt spray 200H, whether it is a single metal multi-layer chromium process. Or multi-layer nickel and chromium process, the corrosion resistance of the coating is difficult to break through the neutral salt spray 200 hours, and these two schemes have the shortcomings of multiple, cumbersome process, high cost, maintenance trouble, and low production efficiency. The production process of multi-wave pulse nanotechnology electroplating high salt spray hard chromium not only improves the corrosion resistance of the coating to 500~1000 hours of neutral salt spray, but also perfectly solves the above process defects.
(3)Because of its unique wear resistance, good corrosion resistance and low price, hard chromium coating is widely used in the automotive industry, aerospace, mechanical parts and plastic mold surface coating. However, the chromium plating layer will produce a large amount of chromium hydride during the electroplating process due to the violent hydrogen evolution reaction, resulting in cracks and pores in the coating. As the chromium coating is a cathode coating relative to the iron matrix, when water, acid, alkali, salt and other media penetrate into the coating defect, iron-chromium will form a corrosion couple, which will lead to the dissolution of the iron anode and the precipitation of hydrogen on the chromium cathode. So the result is that the coating remains, while the substrate beneath it is gradually corroded, and eventually the coating will fall off. Therefore, the cathode coating can only play a mechanical protection role on the matrix when it is intact, once the coating is defective or damaged, not only can not protect the matrix, but accelerate the corrosion of the matrix, so the key to get a high corrosion resistance chromium coating is how to solve the "cracks" and "pores". For cracks, the company has been using self-developed crack-free electroplating technology in the past 6 years and has national invention benefits. Therefore, the company's research and development personnel will focus on the problem of "how to solve the porosity". During the period, the R&D staff consulted a large number of domestic and foreign literature, at the same time, the company reached a strategic partnership with a number of domestic pharmaceutical, additive, high-tech power supply manufacturers, and signed a scientific research cooperation agreement with a number of domestic scientific research institutions and expert teams. Finally, using multi-wave nanoplating technology and customized pulse power supply, the researchers successfully reduced the porosity from 3‰ to 4‰ of ordinary electroplating chromium to less than 1/10,000, reducing by 50 times, and changed the microstructure of the coating. The microphotographs show that the coating obtained under the new process conditions is a nanocrystal chromium multilayer structure. The crystal is fine and the coating cell growth direction is parallel to the bottom direction, which is completely different from the cell growth characteristics of common chromium plating. Because of the special structure of nanocrystalline chromium layers, the defects of single layer can be compensated for each other. It can effectively prevent the external corrosive medium from penetrating into the substrate, so that the corrosion resistance of the coating can be improved several times.
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