1.Why can electrolytes conduct electricity?
Answer: The conductivity of electrolytes is different from that of metal conductors. In metal conductors, current is transported by the movement of free electrons, while in electrolytes, current is transported by charged ions. Due to the equal charge of positive and negative ions in the electrolyte, it does not exhibit electronegativity, which is called electrical neutrality. When we apply voltage to the electrolyte, due to the strong attraction of the electric field, ions run towards the electrodes with opposite polarity to themselves. Cations run towards the cathode, anions run towards the anode. Their movement allows current to pass through, which is the principle of electrolyte conductivity.
2. During the electroplating process, is it due to the high temperature of the plating solution that causes the hanging fixture to heat up?
Answer: Although the heating of the hanger is related to the temperature of the solution, the main reason is:
(1) The current passing through the hanger is too high.
(2) Poor contact on the hanger, increased resistance and heating of the hanger.
What are the main factors controlling the thickness of the electroplating layer?
Answer: The main factors controlling the thickness of the plating layer are current density, current efficiency, and plating time.
Is the brass plating the same as the bronze plating?
Answer: No, brass coating is an alloy coating of copper and zinc, while bronze coating is an alloy coating of copper and tin.
5. What does Faraday's Law ° represent? Can you explain Faraday's first law and second law?
Answer: Faraday's law describes the relationship between the amount of electricity passing through an electrode and the weight of the electrode reactants, also known as the law of electrolysis. Faraday's first law: The weight of metal deposited during electrolysis is proportional to the current and time passing through the electrolyte. W=KItW - weight of a precipitate (g) K - proportionality constant (electrical equivalent) I - current intensity (ampere) t - duration of current (hour) Faraday's Second Law: When the same amount of current passes through different electrolytes, the weight of the precipitated metal is proportional to the chemical equivalent of each electrolyte. K=CEC - a proportionality constant. E - Chemical Equivalent
6.Why do plated parts need to be washed with clean water from chemical degreasing to weak acid corrosion?
Answer: Because most chemical degreasing solutions are alkaline, if the degreasing solution is directly brought into an acid corrosion solution, it will cause a neutralization reaction between acid and alkali, reducing the concentration and effect of the acid. The products of neutralization reaction adhere to the workpiece, which will affect the quality of the coating. After chemical degreasing, the workpiece must be thoroughly rinsed with clean water before entering the acid corrosive solution.
7. What are the common causes of burrs and coarse particles on the electroplated layer, and how can they be resolved?
Answer: The appearance of burrs and coarse particles on the coating is mainly caused by contamination of the plating solution by suspended impurities. Its sources are: dust in the air, sludge from the anode, and hydrolysis products of metal impurities. In addition, there are issues such as abnormal composition of the plating solution and unsatisfactory operating conditions. The solution is to adjust the composition of the plating solution and operating conditions. If it is caused by suspended impurities, the plating solution should be filtered.
What is the basic procedure for preparing electroplating solution
Answer: The basic procedure for preparing electroplating solution is as follows:
(1) Put the required electroplating medicine with a good amount of juice into the cutting tank (small tank) first, and then add an appropriate amount of water to dissolve it. Be careful not to pour the medicine directly into the plating tank.
(2) The impurities contained in the solution can be removed by various chemical methods and treated with activated carbon.
(3) Filter the processed and settled solution into a clean plating bath and add water to the standard amount.
(4) Adjust the plating solution process specifications (pH value, temperature, additives, etc.).
(5) Finally, low current density is used for electrolytic deposition to remove other metal ion impurities until the solution is suitable for operation.
Why does Guiju need to be coated with insulation material?
Answer: In general, except for the hooks and conductive parts in contact with the product, all other parts of the hanger manufacturing should be coated with insulating materials to reduce current loss and metal loss, ensure effective electroplating of the product area, increase effective current, and make the hanger durable.
What is the rust removal effect of sulfuric acid and hydrochloric acid? Can nitric acid remove rust?
Answer: The best way to remove rust from products is usually by using concentrated hydrochloric acid, which can achieve high efficiency. Even if the time is too long, it will not cause excessive corrosion or damage to the base metal. Sulfuric acid is good for removing surface rust stains, but rust removal is slow, and over time, it can lead to excessive corrosion, causing significant damage to the product substrate. Nitric acid cannot be used for rust removal because it has strong oxidizing properties and oxidizes when it comes into contact with metals, producing a large amount of highly toxic nitrogen oxide gas.
What is the impact of pre-treatment on the quality of electroplated coatings?
Answer: Long term production practice has proven that most quality accidents in electroplating production are not caused by the electroplating process itself. Most likely due to improper pre-treatment of metal products before plating. Especially the smoothness, adhesion, and corrosion resistance of the coating are closely related to the quality of the pre-treatment before plating. The surface condition and cleanliness of metal products before electroplating are important factors in obtaining high-quality coatings. It is difficult to obtain a smooth and bright coating on rough metal surfaces, and the coating has many pores, which reduces the corrosion resistance. If there is some kind of grease on the metal surface, normal coating cannot be obtained.
What is the definition of free cyanide in cyanide plating solution?
Answer: In cyanide plating solution, excess cyanide that is not bound to the complex salt is called free cyanide. For example, the free cyanide in cyanide copper plating solution forms excess cyanide other than [Cu (CN) 3]=complex ions.
Why does the content of free cyanide increase due to passivation and poor dissolution of the anode in cyanide copper plating?
Answer: During cyanide copper plating, the anode dissolution is poor. Although some cyanide ions are oxidized and consumed on the anode, more free cyanide ions are generated on the cathode due to the discharge of copper cyanide complex ions, resulting in an increase in the content of free cyanide in the plating solution.
What impact does the anode material of acidic bright copper plating have on the quality of the coating?
Answer: In the acidic bright copper plating process, if electrolytic copper anode is used, copper powder is easily generated, causing rough coating, and the consumption of brightener is fast. Therefore, copper anode containing a small amount of phosphorus (0.1-0.3%) should be used to significantly reduce copper powder. But if a copper anode with a high phosphorus content is used, it will deteriorate the solubility of the anode, resulting in a decrease in the copper content in the plating solution.
In nickel plating solution, when the anode area decreases and the anode current density increases, does the pH value of the solution rise or fall?
Answer: The pH value of the solution decreases. This is because the anode decreases, the current density increases, and the anode becomes passivated but does not dissolve. After anode passivation, oxygen is released, and H+in the solution increases.
