Measurement of Effective Area of Metallization at Galvanic Processes

Abstract

The features of measuring the area of conductive coatings of complex topologies in the process of galvanic metallization are considered. It is shown that when developing and studying hybrid layered structures, it is most difficult to evaluate the effective area of conductive metal and inorganic surfaces and electrodes. The analysis of the applicability of various methods of calculation and modeling for the design of conductive surfaces in a complex topology of the electric field and many influencing factors. It is established that the currently dominant optical methods do not provide the required reliability of the control of the effective area of conducting surfaces. It is proved that only the use of ion flux allows measuring the coating area taking into account the topology of the electric field of the metallized surface. The principle of measuring the geometric mean area of the galvanic couple was selected based on its dependence on the ratio of the equivalent conductivity of the galvanic circuit to the electrical conductivity of the electrolyte. An algorithm has been developed that allows for experimentally determining the metallization area of the product Sk, in which the correction of the result of measuring the cathode area on the topology of streamlines and the marginal fields of the metallized surface are performed automatically.

Measuring transducers “current I - voltage UI”, “voltage U - voltage UU“ and correcting transformations of the contact potential difference, the average length of the current lines, and the reciprocal area of the anode into normalized voltages were selected. The conditions and criteria for normalization and coordination with analog-to-digital converters are determined. At the ADC output, current codes NI and voltage NU and the corresponding parameters of the measurement conversion process are generated.

The block diagram of the measuring transducer of the metallization area is synthesized. It consists of a measuring and installation unit and a processor. The product - a cathode, an anode and a set of sensor electrodes are placed into a bath with electrolyte. The power source creates a direct current in the bath, which is converted by measuring transducers into codes of voltage, current, specific conductivity of the contact potential difference, the average length of the current lines and the inverse area of the anode. The processor implements the measurement conversion algorithm and generates a measurement signal USk proportional to the effective product area Sk and / or NSk code. It is shown that automation of the measurement conversion is possible in the power supply modes of galvanic installations by pulsed and pulsed-reverse currents. In the pulse power mode, it is proposed to introduce integrators into the blocks operating in the pulse mode. In the pulse-reversible mode, correlation filters should be introduced into these blocks.

A measuring setup for measuring the area of electrically conductive parts during metallization in pulsed and pulse-reversed modes has been developed. The inclusion of synthesized meters in the system of automatic control of the current of galvanic baths ensures a reduction in the consumption of materials, energy saving, and an increase in the level of automation of coating.