In the production process of using hard chrome additive, to obtain a hard chromium coating with a certain gloss, and the coating needs to have high hardness, good wear resistance and good adhesion, which operating points should be paid attention to?
According to the site experience and the characteristics of the hard chrome additive Cr-2, Bigolly Technology has made an analysis, and has taught you six key points of operation during production:
1. No matter what material the workpiece is made of, the workpiece needs heat treatment, because the hard chromium plating time of the workpiece is longer, the coating is thicker, the internal stress is larger, and the hardness is higher.At this time, the coefficient of thermal expansion between the base metal and chromium is quite different. If hard chromium is plated without heat treatment, the base metal is prone to peeling due to thermal expansion.
2. Hangers shall be made of materials that are insoluble in chromic acid solution and will not undergo chemical reaction.The clamp shall have sufficient cross-sectional area and maintain good conductivity, otherwise, the current will be high, the voltage of the slot will rise, and local overheating will occur during the production process.
3. During hanging plating production, the angle of workpiece suspension shall be considered to facilitate the escape of gas and prevent the occurrence of air bag phenomenon, which may lead to local non-coating or uneven coating thickness.
4. Pictorial anodes shall be used for hard chromium plating of workpieces with complex shapes, and cathodic protection shall be applied at both ends of the workpieces for cylindrical workpieces to avoid burning at both ends of the workpieces and thin coating in the middle, while metal wires shall be used for shielding of workpieces with edges and corners.
5. In order to improve the adhesion of hard chromium coating on the workpiece, reverse current, large current impact and stepped power supply can be carried out during electroplating.For example, the cathode current density is 30~40A/dm2 and the time is 0.5~3min during reverse current; The current density is 80~120A/dm2 under high current impact, and the time is 1~3 minutes.
6. After hard chrome plating on iron and steel workpieces, hydrogen removal treatment shall be carried out to avoid hydrogen embrittlement in the coating of workpieces.
Therefore, we should pay attention to the above six operating points in the process of using hard chrome additives, effectively improve production quality and greatly reduce production costs.If you are interested in hard chrome additives, please contact Bigolly customer service for free samples and detailed technical information!
If you want to know more about chrome plating, you can check "Electroplating encyclopedia".
