100 Questions on Basic Electroplating Knowledge (Part 9)
Separated Letters Gold Metal Logos
41.Why should metals be plated?
Answer:When metal is used in different environments, metal corrosion occurs due to the chemical and electrochemical effects of external agents on the metal surface. The result of metal corrosion is not only the loss of the metal itself, but also the loss of value due to damage to the structure of the metal product, resulting in a waste of human and material resources, the value of which is many times greater than the metal itself. Therefore, in the mass production of metal and metal products at the same time, it is necessary to fight against metal corrosion. Electroplating process is to increase the protective properties of metal and improve the quality of the metal surface of one of the most effective methods. Plating of metal products is to protect the metal from corrosion, improve the performance of metal products and increase the aesthetics of the product surface.
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42.What is the pH value of the plating solution?
Answer: The pH value of plating solution refers to the acidity and alkalinity of the solution. As we know, water is a weak electrolyte, it can also be ionized.
Ionization of water is very small, under normal conditions, 10 million liters of water, only one gram molecules of water ionization, that is to say, in each liter of water hydrogen ions and hydroxide ions concentration of 1/100000000 grams of equivalent, therefore, it can be said that: in the neutral aqueous solution, the concentration of hydrogen ions or hydroxide ions for 10-7 grams of equivalent.
Hydrogen ions are common to acids and hydroxide ions are common to bases, so the concentration of hydrogen ions and hydroxide ions in a solution directly reflects the acidity or alkalinity of the solution. In a neutral solution, the solution is neutral because the hydrogen and hydroxide ion concentrations are equal. If we change the concentration of one of the ions in a solution, the nature of the solution will change. If we increase the concentration of hydrogen ions in the solution, the solution will change from neutral to acidic. If we increase the concentration of hydrogen ions by 10 times, the concentration of hydrogen ions in the solution will be 10-6, and if we increase it by 100 times, it will be 10-5, and so on; on the other hand, if we decrease it by 10 times, the concentration will be 10-8, and if we decrease it by 100 times, it will be 10-9.
The pH value is the absolute value of the logarithm of the base 10 to express the concentration of hydrogen ions, also called the index of hydrogen ions. That is to say: when the concentration of hydrogen ions in the solution is 10 negative several times the square, the pH value is equal to a few, when the pH value is equal to 7, the concentration of hydrogen ions in the solution is 10-7, the solution is neutral. pH changes from 7 to 0, the solution is acidic, pH changes from 7 to 14, the solution is basic.
43.How many methods are commonly used in factories to determine the pH value of a solution?
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Answer:pH is an important parameter of electroplating bath, which has a great influence on the plating process, so it is necessary to check the pH value of plating solution frequently. Factory commonly used to determine the pH value of the solution has two methods: (1) test paper method: according to the test paper changes color, and the known pH value of the color scale compared to determine the pH value of the solution. The advantage is convenient and simple; the disadvantage is that the error is large. This is the most widely used method in the daily production of factories. (2) pH tester: according to the hydrogen ion concentration of hydrogen electrode produces a different potential and a standard electrode potential difference between the potentiometer display readings. The advantage is high accuracy; the disadvantage is that the test is more complex.
44.What is called DC power supply?
Answer: DC is the same direction of the electrons in the positive and negative electrode between the flow of current. Electroplating in the power supply are used for direct current, the voltage is generally 6 to 12 volts. Because the voltage is too low, not from the outside world by the transmission line supply. Usually obtain direct current method: (1) DC generator; (2) rectifier; (3) battery.
45.ammeter, voltmeter should be how to connect?
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Answer: the ammeter that ammeter is the indication of the size of the current through the circuit of the instrument, the measurement range of the ammeter, generally can be directly connected in series on the circuit, the larger (30 amps or more) is required to use a shunt in series with the circuit, the ammeter is connected to the shunt on both ends. But there are also some 5 amp ammeter as usual need to use its matching shunt. Voltmeter that is, voltmeter, is the measurement of voltage, generally connected in parallel with the load, as long as its two wires across the poles of the circuit, you can indicate the reading, the current, voltmeter in the connection must pay attention to the polarity and range.
