Why is the Electroless Nickel Plating Solution for Electric Heating Tubes Unstable

Why is the Electroless Nickel Plating Solution for Electric Heating Tubes Unstable

Chemical nickel plating manufacturers will introduce to you why the chemical nickel plating solution is unstable.

1、 Reasons for instability of electroless nickel plating solution

1. When gas slowly releases from the inside of the plating solution and begins to decompose on its own, the gas not only releases on the surface of the plating piece, but also slowly and evenly throughout the entire plating solution.

2. If effective measures are not taken in time, the gas will escape faster and faster, and a large number of bubbles will be generated, making the bath foam like.

3. Formation of black coating or deposit When many foam appear in the electroless nickel plating solution, rough black coating begins to form on the plated parts and the device wall, or many irregular black granular deposits are generated in the plating solution.

4. During the process of self decomposition, the color of the plating solution gradually fades. For example, in alkaline chemical nickel plating solution containing ammonia, when self decomposition occurs, the color of the plating solution changes from dark blue to blue white. At the same time, a pungent ammonia odor can be smelled. When the ammonia odor disappears, the chemical nickel plating solution has completely decomposed.

2、 The main factors affecting the instability of plating solution

1. Improper ratio of plating solution

① If the concentration of hypophosphite (reducing agent) is too high, increasing the concentration of hypophosphite in the plating solution can improve the deposition rate. However, when the deposition rate reaches, continuing to increase the concentration of hypophosphite will not only slow down the deposition rate, but also cause the plating solution to decompose on its own.

② If the concentration of nickel salt is too high, it will increase the concentration of nickel salt. When the pH value of the plating solution is too high, it is easy to generate nickel phosphite and nickel hydroxide precipitates, which can make the plating solution turbid, easily trigger the self decomposition of the plating solution, and cause many particles on the surface of the workpiece.

③ One of the important functions of the complexing agent is to increase the precipitation point of nickel phosphite in the plating solution when the concentration of the complexing agent is too low. When the nickel salt concentration, temperature, and pH value of the plating solution are constant, the solubility and precipitation point of nickel phosphite in the plating solution are also constant. If the concentration of the complexing agent in the solution is too low, as the chemical nickel plating proceeds, the phosphite ions will continue to increase and quickly reach the precipitation point of nickel phosphite, resulting in precipitation. These precipitates will be one of the triggering agents for the self dissolution of the plating solution, and also one of the reasons for the presence of many particles on the surface of the workpiece.

④ If the concentration of pH value adjusting agent is too high, under the condition that other components of the plating solution remain unchanged, if the pH value is adjusted too high, it is also easy to precipitate nickel phosphite and nickel hydroxide, and accelerate the decomposition of reducing agent, which is also one of the reasons for many granular particles on the surface of the workpiece.