- Mar 17, 2018 -
(1) DC generator stage This type of power source consumes large amounts of energy, is inefficient, and has high noise. Has been eliminated.
(2) The silicon rectifier stage is a new generation of DC generators. The technology is very mature, but it is inefficient, bulky, and inconvenient to control. Many companies still use this kind of electroplating power supply.
(3) The silicon controlled rectifier stage is a mainstream power source that replaces the silicon rectifier power supply, and it is characterized by high efficiency, small size, and easy control. With the core device - the SCR technology matures and develops. The power technology has matured and it has been widely used.
(4) Transistor switching power supply, ie pulse power phase pulse electroplating power supply is the most advanced electroplating power supply. Its appearance is a revolution of electroplating power supply. This power supply has a small size, high efficiency, superior performance, stable ripple coefficient. And it is not easily influenced by the output current. Pulsed plating power is the direction of development and is now beginning to be used in enterprises.
1.1 High corrosion resistance zinc alloy plating process
Zinc alloy refers to an alloy containing zinc as a main component and containing a small amount of other metals. The binary zinc alloys that have been used for production are: Zn-Ni, Zn-Co, Zn-Fe, Sn-Zn. Zn-Ti, Zn-Cr, Zn-P, Zn-Mn, etc. are still in development trials and trials, zinc alloy has good protection performance, it is often referred to as high corrosion resistant alloy coating, which is more research and application The most widely used are alloys of zinc and iron group metals, namely zinc-nickel, zinc-cobalt and zinc-iron. The atomic structures and properties of iron family metals are similar, and their co-deposition properties with zinc are similar. From the viewpoint of electrode potential, the iron group metal has more positive potential than zinc, but when co-deposited, zinc is preferentially deposited and deposited preferentially than iron group metal. This kind of deposition is called anomalous co-deposition. The reason is that when zinc and iron group metals are co-deposited on the cathode surface, the pH of the surface increases with the precipitation of H2 on the cathode surface, and a zinc hydroxide colloidal film is formed on the cathode surface, so that the iron group metal ions are exposed on the cathode surface. It is inhibited and difficult to deposit, so zinc preferentially precipitates on the surface of the cathode.
1.1.1 Electro-galvanized-iron alloy process and passivation
There are two types of zinc-iron alloys that have been industrially used. One is an alloy with a high iron content. The coating is not easily passivated, and it is easily phosphatized. It has good adhesion to paint and is used for the surface treatment of steel sheets and strips. , as the bottom of the electrophoretic paint; the other is a zinc-iron alloy containing trace amounts of iron, the coating is easily passivated, corrosion resistance is excellent, especially through the black passivation, its corrosion resistance has greatly improved. The zinc-iron alloy process can also be divided into two types, acidic and basic. The iron content of the alloy coating is generally between 0.2% and 0.7%. The content of ferric ions in the bath cannot be too high, otherwise the cathode current efficiency will be reduced. Crystallized. The following only describes the low iron content plating process.
Electroplating is a widely used surface optimization treatment technology in the jewelry production process, and is a method for electrochemically depositing metal and alloy plating on the surface of the jewelry. The so-called electroplating is that the metal ions in the plating solution are reduced to metal atoms through an electrode reaction under the action of an external electric field, and metal precipitation is performed on the cathode, thereby forming a plating layer on the jewelry surface, thereby effectively changing the jewelry's Texture, color, texture, to prevent alteration, play a role in beautifying and prolonging the service life of jewelry.
According to the purpose of the use of electroplating classification, electroplating can be divided into protective plating and decorative plating two.
Protective electroplating is mainly used to prevent metal corrosion, usually using galvanizing, rhodium plating, tin plating, and the like. It is commonly used on silver jewelry. We know that silver is very easy to oxidize and darken, which is bad for jewellery and is usually protected by electroplating. The 925 silver jewellery of Baodi Network has rhodium plating. Tantalum is an expensive precious metal, stable in nature, and white in color. Like platinum, it can effectively prevent 925 silver oxidation from becoming black and beautiful.
Decorative electroplating is mainly for decorative purposes, of course, there will be some protection. To beautify, most decorative electroplating is a combination of multiple layers of electroplating. It is usually on the jewellery that it is first coated with a base layer, then with the surface layer, and sometimes with an intermediate layer. This kind of electroplating is widely used in precious metal plating and artificial jewelry. This type of electroplated jewelry, plating is often very high-grade precious metals, such as gold, 18k gold, colored metal, etc., and its basic material is often a small hardware, or non-precious materials.
The electroplating plating parts of plastics are easy to float, and are easily burned when they come in contact with the hangers. Because the specific gravity of plastics is small, they float easily in solution.
The shape of the lampshade is like a small plate. The inner surface is recessed and there are two small holes on the side. At the beginning, only one copper wire is used to clamp the two small holes for electroplating.
Due to the release of gas during electroplating, the lampshade is easily detached from the copper wire, and the copper wire is also light enough to immerse the lampshade in the solution. Later on the copper wire attached to heavy objects, to solve the floating problem. The contact point between the copper wire and the lampshade is scorched and the plastic is exposed, which is caused by poor conduction.
Solution: In order to solve the floating and conductive problems of the plastic plating workpiece, we designed a special fixture. The clip has a certain weight. After the lampshade is no longer floated, two wider conductive pieces are stuck on the hole of the lampshade so that the current is even and the contact point is not burnt.