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In which cases do you choose a bell electrolyzer for electroplating? Draw example.
Bells and drums are made of plastics and steel (in the latter case they are lined), they are equipped with perforations - small holes in the side walls and mostly small parts are loaded in them. During operation, the bells and drums rotate. Electric contact in electrowinning baths and for the application of electrochemical coatings is provided with the help of special devices (flexible spikes, bolt heads, metal rims, etc.) inside the drums. Since in practical conditions not all the parts are in contact with the power source, an amendment is made simultaneously in the calculation of the cathode current densities. Current supply to the bath is carried out with current-carrying buses. For each bath set an individual source of current. The material for manufacturing can be different, but fiberglass has several advantages: 1. Absence of welds, which are the most vulnerable places. 2. Integrity of the internal surface of prefabricated structures (Type - monolith). 3. High corrosion resistance in aggressive environments. 4. Increased vibration resistance in comparison with various metals, alloys due to reinforced - laminated structure. 5. At temperature differences, the coefficient of structural expansion / contraction is two to three times less than for metals, special steels and alloys. 6. Individual technological developments make it possible to manufacture products of various complexity and shape, in contrast to products made of metals and alloys, the production of which is limited by rigid standards. 7. Lower density of fiberglass in comparison with metals and alloys makes manufacturing, transportation, installation, operation and repair of products much easier. At the same time the specific strength of products made of fiberglass is higher than that of products made of metals and alloys. 8. Depending on the environment and temperature conditions, in which products made of fiberglass will be used, their durability can reach 60 years. 9. Products made of fiberglass do not conduct electric current.
Processes of diffusion saturation of surfaces of metal parts with chromium or processes of depositing a chromium layer from an electrolytic solution under the influence of an electric current are called chrome plating. Processing of products by the method of chromium plating can be used as a decorative treatment, as well as to protect against corrosion and increase the hardness of the surface of the product. The chromium layer applied to the object increases its operational properties and extends the service life. To apply a layer of chromium to the surface of objects, several methods are used, initially the galvanic coating of the metal Types of chrome plating and technology Classification of chrome plating is carried out by the method of applying chromium to the part. The most widely used electrolytic and diffusion, a little less known - chemical chromium. The resulting coating may vary slightly in strength, appearance. Electrolytic (catalytic) chromium is perhaps the most well-known method of surface metallization. Actively used by motorists, in view of the great demand and popularity of catalytic chrome plating of parts of cars and motorcycles are engaged in small firms that usually use a galvanic shop for the premises of the usual garages, so in people this method is also called "garage", and the most popular service can be considered chromium plating Disks. Processing Modes. Depending on the treatment mode, the coatings obtained differ in their qualities - both external and internal: "Milk chrome" - not very hard coating, which has a non-porous, elastic surface. It is obtained by the action of an electric current density of 15-25 A / dm.kv. On the electrolyte at a temperature of 65 to 80 °. "Brilliant chrome" - the most hard and wear-resistant coating, which is characterized by a mirror shine. Appears at average values of temperature and current densities, the recommended ranges are 45-60 ° C for the first parameter and 30-100 A / dm. For the second. "Hard chrome" - the resulting layer of chromium will be the hardest, but also the most fragile in comparison with the previous species. The thermal regime is set at low temperatures (up to 40 °), the current density is above 100 A / dm2. Preparation for the chromium deposition process involves several steps: · Polishing and polishing the surface of the chrome part; · Washing for soiling and rubbing with rags; · Isolation of the surface, where the application of chromium should not be done, the filling of the holes (if chromium coating and internal cavities are not required); · Mounting the parts to the suspension; · degreasing; · Washing in water; · Pickling. Technological process of chromium plating Galvanic coating is carried out by solutions of six- or trivalent chromium. As hexavalent chromium, chrome anhydride is used, as the trivalent chromium sulphate or chromium chloride. In the galvanic bath, in addition to the chromium-containing solution, sulfuric acid is also added. After placing the workpiece in the solution, a current of a certain density is fed into the solution. The solution in the bath must have a certain temperature set in accordance with the metallization regime. The thermal regime must be maintained at the same level throughout the entire chromium process, the process failures can reduce the adhesive properties of the chrome coating, and lead to the fact that the galvanic coating will have a heterogeneous structure (stains, stalactite outgrowths). In the process of galvanizing, harmful vapors are generated from the electrolytic solution, so all work must be carried out in compliance with safety regulations, using personal protective equipment. In some cases, chromium plating is performed only after etching or after the preliminary application of a layer of another metal (copper or nickel) - this contributes to the hardening of the layer formed. To seal chrome pores, the part is additionally covered with oil or varnish, and for the strengthening of the formed chromium film, heat treatment is carried out - for some time at a very high temperature (about 200 °). As mentioned above, electroplating-chromium plating is used to create a protective-decorative layer or to impart special properties to the surface. Decorative chromium is applied to a sublayer of another metal - copper or nickel, this method contributes to the long-term preservation of the chromium shine, prevents corrosion of the surface of the part through the pores of the chromium layer. Hard chromium plating is used where it is necessary to increase wear resistance, hardness to reduce friction on the workpiece. In this case, a layer of another metal is not required, aging in the bath has a long duration, so that the resulting layer of chromium is of increased thickness. Unlike decorative, hard chromium plating should be completed by additional treatment with varnishes or oils.   Что будет с Землей, если ось ее сместится на 6666 км? Что будет с Землей? - задался я вопросом...  Что вызывает тренды на фондовых и товарных рынках Объяснение теории грузового поезда Первые 17 лет моих рыночных исследований сводились к попыткам вычислить, когда этот...  ЧТО ПРОИСХОДИТ, КОГДА МЫ ССОРИМСЯ Не понимая различий, существующих между мужчинами и женщинами, очень легко довести дело до ссоры...  Конфликты в семейной жизни. Как это изменить? Редкий брак и взаимоотношения существуют без конфликтов и напряженности. Через это проходят все... Не нашли то, что искали? Воспользуйтесь поиском гугл на сайте:
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