JPH0119070Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electroless nickel plating solution concentration measuring device that can always accurately measure the concentration of an electroless nickel plating solution.

Accurate measurement of the concentration of electroless nickel plating solution, especially its metal salt concentration, is important for controlling the metal deposition rate and plating quality. equipment is provided. Conventional plating liquid concentration measurement equipment consists of a circulation pump, a cooler that cools the plating liquid to a temperature suitable for measurement, and a colorimeter for measuring metal salt concentration. The plating liquid is sent to the colorimeter via the cooler, and after the concentration is measured there, the plating liquid is returned to the plating tank again. However, when the concentration measurement is stopped, the temperature of the plating solution inside the concentration measuring device described above gradually decreases, causing recrystallization, which may cause clogging. Both the temperature of the plating solution and the temperature of the plating solution inside the concentration measuring device may drop and recrystallize, and the crystals in the plating tank may be dissolved by the heating means of the plating tank when plating work is resumed. However, since the crystals inside the concentration measuring device, which does not have a heating means, cannot be dissolved, there is still a risk of clogging. In addition, in conventional concentration measuring devices, there is a risk that metal particles, etc., which inevitably precipitate in the wetted parts of the plating tank, may come off and get mixed into the concentration measuring device. Another drawback was that accurate concentration measurements could not be made because the transmittance indicator value decreased.

The present invention was completed with the aim of providing a concentration measuring device for electroless nickel plating solution free from the above-mentioned drawbacks, and will be described in detail below with reference to the illustrated embodiments.

Reference numeral 1 denotes an electroless nickel plating tank, in which a plating solution mainly composed of nickel sulfate and sodium hypophosphite is stored, and this plating solution is heated to about 90°C by a steam pipe 3. heated. 4 is a washing tank for washing the plated object after plating is completed, and the washing water in the washing tank 4 is supplied from a supply section 5 and flows out from a discharge section 6, thereby suppressing dirt within a certain range. There is. Reference numeral 7 denotes a circulation line for measuring concentration that circulates the plating solution in the electroless nickel plating tank 1. In the middle of this circulation line 7, the temperature of the plating solution is lowered to about 50°C, which is suitable for measurement. A cooler 8, a colorimeter 9 having a wavelength of about 700 nm, and a circulation pump 10 are installed for the purpose of increasing the temperature, and a three-way pump 1 is installed on the inlet side of the circulation pipe 7 near the outlet 11.
3 is provided so that the take-out pipe 14 branched from the three-way pot 13 faces the washing tank 4, and a circulation pipe 7 is provided between the three-way pot 13 and the cooler 8.
A separator 12 with a built-in filter is provided. The separator 12 is designed to prevent nickel-phosphorus alloy particles generated in the wetted parts of the electroless nickel plating tank 1 from entering the circulation pipe 7, and is designed to have a large diameter. By reducing the internal flow velocity, the particles are allowed to settle, and by increasing the overall length, the inflowing particles are prevented from flowing out into the circulation pipe 7 as they are. As a result, the electroless nickel plating tank 1 is introduced into the circulation pipe 7.
This is so that the plating liquid inside the tank 4 and the washing water inside the washing tank 4 can be introduced selectively. In addition, as shown in the figure, the separator 12 is connected to the washing tank 4.
This reduces the load on the cooler 8 when sending the boiling liquid heated to about 90°C into the circulation pipe 7.

With this structure, when measuring the concentration of the plating solution, the three-way pot 13 is used as shown in the figure to disconnect the extraction pipe 14 and the circulation line 7, and the circulation pump 10 is operated. The plating solution in the electroless nickel plating tank 1 is circulated through the circulation pipe 7.
If the plating solution is made to circulate within the plating solution, even if particles of nickel-phosphorus alloy are mixed in, these particles will settle in the separator 12 and will be reliably separated by the filter built in the separator 12. Taueko is cooled to about 50°C by the separator 12 and the cooler 8, which is suitable for concentration measurement, and reaches the colorimeter 9, where the light transmittance at a wavelength of 700 nm is measured to determine plating. Since the nickel concentration in the liquid will be measured, the nickel-phosphorous alloy particles are separated before reaching the colorimeter 9, and there is no risk of recrystallization at a temperature of about 50°C. The nickel concentration is accurately measured, and then the plating solution whose concentration has been measured is returned to the electroless nickel plating tank 1. After stopping the concentration measurement, the three-way pot 13 is switched while the circulation pump 10 is still operating, and the washing water in the washing tank 4 is sucked into the circulation pipe 7, and the plating liquid in the circulation pipe 7 is removed. Circulation pump 1 after replacing with flush water
0, recrystallization will no longer occur even when the temperature inside the circulation pipe 7 drops to room temperature, and even if the plating operation itself is stopped, recrystallization will still occur in the circulation pipe 7. It will turn out to be nothing. Therefore, after the plating work is restarted and the temperature of the plating liquid has been raised to about 90°C by the steam pipe 3, the plating liquid can be sucked into the circulation pipe 7 by operating the three-way pot 13. For example, the washing water in the circulation pipe 7 is returned to the electroless nickel plating tank 1 so that concentration measurement can be carried out at any time.

As is clear from the description of the above embodiments, the present invention includes a separator with a built-in filter at the inlet of a circulation pipe for concentration measurement, which has a cooler, a colorimeter, and a circulation pump in the middle. Therefore, even if metal particles generated in the wetted parts of the plating tank are sucked together with the plating liquid, they will be reliably separated in the separator and the transmittance of the colorimeter will be reduced, as seen in conventional plating liquid concentration measuring devices. The concentration of the plating solution is reduced without decreasing the indicated value, and the plating solution is sent to the colorimeter after being cooled to a temperature suitable for concentration measurement by the separator and cooler in the washing tank. can be measured accurately and easily, metal salts, reducing agents, etc. can be appropriately replenished, and plating quality can be properly controlled. Furthermore, since a three-way tap is provided on the inlet side of the circulation pipe for selectively introducing plating liquid and washing water into the circulation pipe, the three-way plug can be switched when the concentration measurement work is completed. The plating solution remaining in the circulation pipe can be replaced with washing water, eliminating the risk of recrystallization occurring in the circulation pipe while concentration measurement work or plating work itself is stopped. Trouble caused by clogging can be completely prevented.Furthermore, in this invention, since the washing water used to wash the covered objects is used to prevent recrystallization, special equipment is not required. It also has the advantage that it can be easily incorporated into conventional plating equipment without installing a new device, and has extremely great practical value as a device that eliminates the drawbacks of conventional plating solution concentration measuring devices.

[Brief explanation of the drawing]

The drawing is a flow sheet showing an embodiment of the present invention. 1... Electroless nickel plating tank, 4... Washing tank, 7... Circulation pipe, 8... Cooler, 9... Colorimeter, 10... Circulation pump, 12... Separator, 13
...Mikata Kotuku.

Claims (1)

[Scope of utility model registration request] A cooler 8, a colorimeter 9, and a circulation pump 10 are installed on the inlet side of the circulation pipe 7 for measuring the concentration of the plating solution in the high-temperature electroless nickel plating tank 1, and inside the washing tank 4. An apparatus for measuring the concentration of an electroless nickel plating solution, characterized in that it is equipped with a separator 12 and a three-way pot 13 for introducing the washing water in the washing tank 4 into the circulation pipe 7.