| Suzhou Borui Industrial Material Science & | | | | thousands of amperes during this one hour of |
| Technology CO.,LTD is a leading manufacturer and | | | | processing time. It is easy to see why power costs |
| exporter of Titanium Anode.Platinized Titanium | | | | are major cost component for a facility that |
| Anodes .Platinized Niobium Anodes .MMO Coating | | | | processes large quantities of electroplated sheet |
| Titanium Anodes .We specializing in the production of | | | | product. |
| Titanium Anode, put emphasis on Dimensionally Stable | | | | Product Types |
| titanium Anode, the application of cathode material in | | | | The most common electroplated coating for steel |
| electrochemistry and research and development of | | | | sheet products is zinc. Electrogalvanized zinc coatings |
| plating. | | | | are used by a number of automotive companies for |
| Introduction | | | | exposed car-body panels, where the typical coating |
| The development of modern continuous sheet | | | | mass ranges from about 50 to 80 g/m2 per side. |
| galvanizing lines has led to the disappearance of most | | | | These coatings are considerably thicker than the |
| of the old manual mills for galvanizing cut sheets. | | | | electrogalvanized coatings typically used for |
| There are however still some machines that galvanize | | | | non-automotive applications, so the lines built to make |
| cut-to-length sheets; they use chemical pretreatment | | | | products for automotive applications usually have a |
| sequence similar to those for wire or tube galvanizing. | | | | large number of plating cells. Also, each automotive |
| Platinized Titanium Anodes | | | | customer has their own specific coated-product |
| At the beginning of the line, the end of one coil is | | | | specification. |
| welded to the start of the next coil. Then there are | | | | Another attribute associated with the use of |
| two basic methods for continuously galvanizing sheet | | | | electrogalvanized coatings for automotive applications |
| which differ in the way that the strip is cleaned | | | | is excellent surface finish that is attainable with the |
| before galvanizing-chemically or by thermal | | | | electroplating process. Twenty-five years ago, when |
| treatments. Coils of annealed cold reduced sheet may | | | | automotive companies began using large amounts of |
| be fed directly to the galvanizing line, or alternatively, | | | | galvanized sheet for exposed body panels to |
| coiled sheet is continuously heat treated in the | | | | improve corrosion protection, one of the few coated |
| pretreatment line. After leaving the galvanizing bath, | | | | sheet products that could meet the demanding |
| in which strip only stays for a few seconds, the | | | | surface quality requirements was electrogalvanized. |
| surface is wiped to remove excess zinc and may be | | | | Hot-dip galvanized was, and still is, used for |
| further treated to after the surface appearance, | | | | unexposed body parts. As the surface of hot-dip |
| composition, smoothness or mechanical properties. | | | | products improves, they continue to replace |
| Platinized Titanium Anodes | | | | electrogalvanized sheet for exposed automotive |
| The steel sheet electroplating process utilizes the | | | | body panels. |
| same basic principle as that for conventional | | | | Other zinc electroplating lines have been built through |
| decorative finish electroplating. However, the steel | | | | the years to make thinner coatings. Typically, the |
| sheet process differs in that the electroplated coating | | | | sheet that is made on these lines has a coating mass |
| is applied by passing the strip at high speeds through | | | | of less than 25 g/m2. The applications for this |
| a series of plating cells, building the coating thickness | | | | product are often indoors; applications where the |
| by a small amount each time the strip passes through | | | | environment is not very corrosive. Many applications |
| an individual cell. This continuous process for | | | | involve painted products. These coating lines often |
| electroplating steel strip requires necessary equipment | | | | have the ability to apply paint pre-treatment so that |
| to transport the strip at high speeds (150 to 200 | | | | the customer can paint directly without additional |
| meters per minute and higher) through a series of | | | | in-house treating. MMO Coating Titanium Anodes |
| individual plating cells, and is not as simple as it sounds. | | | | A second type of electroplated coated-steel sheet |
| An Electroplating Cell | | | | being manufactured today has a coating composed |
| The simplest electroplating cell is shown in the sketch | | | | of a zinc/nickel alloy. Typically, the nickel content is 10 |
| where the plating solution bath is zinc sulfate. | | | | to 16 percent with the balance being zinc. The unique |
| Platinized Titanium Anodes | | | | feature of this process is that the zinc and nickel ions |
| This simple plating cell illustrates the actions during the | | | | are co-deposited to make a true alloy coating. It is |
| plating process. At cathode (steel, for example), zinc | | | | not composed of alternating layers. MMO Coating |
| ions dissolved in the zinc sulfate solution combine with | | | | Titanium Anodes |
| two electrons and form elemental zinc, which | | | | The application for this product has been limited |
| deposits onto the cathode surface. At anode, water | | | | primarily to a few automotive companies. These |
| is converted to oxygen and hydrogen ions to | | | | companies have developed in-house product design |
| maintain electrical balance. The oxygen forms a gas | | | | and manufacturing processes to take advantage of |
| and nothing is deposited on the anode surface. The | | | | the unique characteristics of the zinc/nickel coating. |
| plating solution carries the current between the | | | | For these automotive applications, the metallic coating |
| cathode and anode. Platinized Niobium Anodes | | | | is often coated with a special corrosion-resistant thin |
| Plating of Steel Sheet in a Continuous Process | | | | organic coating on top of the zinc/nickel. The zinc |
| There are many types of anode arrangements. | | | | nickel alloy coating is covered by ASTM Specification |
| Some are horizontal, others are vertical, and one | | | | A 918. |
| process utilizes a radial cell wherein the strip passes | | | | A third type of electroplated coating is zinc/iron alloy |
| around large diameter rolls inside each plating cell, and | | | | coating. The attributes of this specialized coating are |
| the anodes have a radial design to match the | | | | somewhat like those of hot-dip galvannealed product. |
| diameter of the large rolls submerged into the plating | | | | Like zinc/nickel alloy, zinc/iron coating is co-deposited |
| solution. Each type of anode arrangement and design | | | | as an alloy coating. Iron is uniformly deposited |
| has advantages and disadvantages; thus, it is easy to | | | | throughout the coating thickness. Also, like zinc/nickel |
| see why different manufacturers use different | | | | coating, zinc/iron coating is used predominantly by the |
| methods. Each requires very close control of the | | | | automotive industry. The attributes of electroplated |
| anode-to-strip spacing to achieve efficient plating, | | | | zinc/iron is that it is relatively easy to weld and paint |
| avoiding arc spots and other defects in the coating. | | | | if the proper electro-priming equipment is available to |
| Platinized Niobium Anodes | | | | the automotive manufacturer. Also, the coating is |
| | | | very hard, making it is less susceptible to scratching |
| Maintenance of the large volume of plating solution | | | | during stamping and handling. This is the important |
| that is contained in all the cells is a science unto itself. | | | | feature since the zinc/iron alloy coated-sheet product |
| Whether the plating solution for electrogalvanizing is | | | | is being used almost exclusively for exposed |
| based on zinc sulfate or zinc chloride chemistry, | | | | car-body panels. |
| maintenance of the proper ranges of zinc ion | | | | Corrosion Resistance of Electroplated Coatings |
| concentration and solution pH are important control | | | | Concerning the corrosion behavior of |
| features. Besides plating zinc, some manufacturers | | | | electrogalvanized versus hot-dip galvanized coating, it |
| have the ability to deposit alloy coatings. This | | | | is important to note that it is essentially equivalent |
| requires, at a minimum, at least one more level of | | | | for identical coating masses. A coating mass of 100 g |
| control of the plating solution. For example, producing | | | | m2 will provide essentially the same amount of |
| a zinc/nickel alloy coating requires close control of the | | | | corrosion protection whether it is a hot-dip galvanized |
| concentrations of both the dissolved zinc and nickel in | | | | or electrogalvanized coating. |
| the solution. Solution control has to be accomplished | | | | The reason that the automotive companies can |
| on a dynamic basis since these lines operate | | | | successfully use a coating mass in the 50 to 80 g/m2 |
| continuously. | | | | range is because they apply additional treatments on |
| Power Requirements | | | | top of the metallic coating, including a zinc phosphate |
| The electroplating process requires a large amount of | | | | coating, an electro-deposited organic-based coating, a |
| electric power to deposit a metallic coating. The total | | | | primer, and multiple-layer finishing paint coatings. |
| power requirement is a direct function of the coating | | | | Clearly, the corrosion resistance needed to protect a |
| thickness that is needed to meet the customer’s | | | | car body panel for over 10 years is more than that |
| specification. For example, the power required to | | | | afforded by the metallic coating alone. Application of |
| deposit a zinc coating mass of 80 g/m2 is | | | | the above coatings over the electroplated metallic |
| approximately twice that required to deposit a | | | | layer results in a synergistic system, whose corrosion |
| coating of 40 g/m2. A typical line that has the | | | | resistance is more than the sum of its individual |
| capability to process 70 to 120 tons/hour with a | | | | components. |
| coating mass of 50 g/m2 will consume hundreds of | | | | |