In the electrodeposition of base solubilized, resinous materials from an aqueous dispersion onto a metal, anodic substrate immersed in the dispersion by passing a direct electrical current through the dispersion and substrate, generally speaking there are two stages in the deposition of the film. There is a first stage in which the current density increases due to a fixed or increasing voltage and relatively low film resistance; and a second stage in which the current density tends to decrease because of the increased resistance of the growing film. In accordance with our invention the overall deposition process is improved by maintaining the current density during the second stage of film deposition at a maximum value, predetermined by small scale experiments, by increasing the deposition voltage above the nominal rupture voltage of the film as required to maintain the relatively high current density value, which is a maximum value suitable for obtaining rapid film deposition and good film throw without damaging the film by boiling aqueous liquid or low boiling cosolvents therein.

A method and arrangement for measuring and recording parameters relative to the onset of coagulation and the build-up of film resistance within an electrodeposition bath system. A rapid voltage rise across the bath system is detected by the arrangement, the rapid rise indicating the onset of coagulation, and the parameters are recorded. Parameters are further recorded by the arrangement during the period of build-up of film resistance.

A measuring method or arrangement for the quick, accurate, and safe measurement of electrical parameters of binders for the electrocoating process is described. According to the arrangement, digital measuring results are obtained by inserting into a deposition circuit a precision resistor R.sub.J (1), a voltage-frequency-converter (2), pertinent counter unit (3), intermediate storage unit (4), and recording unit (5) for recording of the Coulomb yield; a time element (6) for interruption of the impulse sequence coming from said voltage-frequency-converter (2) after from about 50-100 msec., an assigned counter unit (7), an intermediate storage unit (8), recording system (9), a multiplier step (11), which carries out an analogous multiplication of the voltages with one another occurring at said precision resistor R.sub.J (1) and on the voltage divider R.sub.US (10), a voltage-frequency-converter (12) for the conversion of the analogous product from (11) into impulses, a counter unit (13), an intermediate storage unit (14), and a recording system (15).

Method of assessing the effect of periodic inversions of current polarity in electrochemical processes. The method comprises the reading and recording of the variation of the shape and magnitude of the current, the variation of the voltage, the variation of the active internal resistance, and the variation of the electrode potentials during the forward and inverse current intervals and during the transitional regimes of current polarity inversion.

An apparatus for monitoring and adding solution to a plating bath and controlling the quality of deposited metal. At least one monitor monitors at least one condition within a plating bath and produces at least one signal corresponding to the at least one condition. At least one controller receives the at least one signal produced by the at least one monitor, processes the at least one signal, determines whether an additional amount of at least one chemical should be added to the plating bath, and controls at least one valve for controlling flow of the additional amount of the at least one chemical. A pre-mix tank pre-mixes chemicals to be added to the tank. A plurality of holding tanks holds chemicals and supplies the chemicals to the pre-mix tank. At least one valve is arranged between each holding tank and the pre-mix tank. At least one valve is also arranged between the pre-mix tank and the plating bath.