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Titanium was produced by electrolyzing a molten bath of a sodium and potassium chloride mixture containing potassium fluotitanate, I~TiF6, and sodium fluotitanate, Na2TiF6. The formation of trivalent titanium double fluorides of sodium and potassium always preceded the production of metallic titanium during the electrolysis. These new trivalent titanium compounds were positively identified as K2NaTiF6, K~TiF~, and Na~TiF~. Free metallic sodium was deposited at the same time as titanium when using a cooled cathode. This fact together with the measured polarization voltage and the presence of trivalent titanium compounds indicate that production of metallic titanium proceeds by secondary reactions in two steps: first, tetravalent titanium is reduced to the trivalent state; second, trivalent titanium is finally reduced to metallic titanium.Metallic titanium may be produced by electrolysis of potassium fluotitanate, K~TiF~, or sodium fluotitanate, Na~TiF6, in fused halide baths under argon cover. However, due to lack of protective atmosphere during the electrolysis, several experimenters (1, 2) failed to produce Ti by this method. For similar reasons (3) the formation of some titanium oxyfluoride compounds was observed while conducting electrolysis in open tubes.Recently, positive results were obtained (4) on the production of Ti metal by electrolyzing, under an argon atmosphere, potassium fluotitanate K_~TiF, dissolved in NaC1; the outstanding industrial possibilities of this process have been shown.The present authors (5) reported some of their results on the production of Ti by electrolysis of sodium and potassium fluotitanates in a mixture of fused sodium and potassium chlorides conducted in an argon atmosphere, and they have shown that this electrolysis lent itself very well to the study of the mechanism of the reaction involved in the production of metallic Ti.In the present work, special attention has been paid to the determination of polarization voltages and of intermediary compounds appearing during electrolysis in order to find out more definitely by which steps the production of Ti occurred and also to verify if Ti was produced directly by electrolysis as a primary product or if it was the result of a secondary reaction between Ti compounds and Na formed as a primary deposit. ExperimentalElectrolysis was studied in graphite cells with ordinary or water cooled cathodes and also in Ushaped fused quartz cells using either a normal cathode or a rotating cathode with a dry salt injection system. Polarization voltage considered as the back emf of the over-all reaction was measured by the interruptor-commutator method using an electronic voltmeter.Gases were analyzed in a mass spectrometer for chlorine and fluorine. The cathode products and the residual melt were submitted to a combined chemical, spectrographic, and x-ray analysis.The electrolytic celL-- Fig. 1 represents a section through the furnace and the electrolytic graphite cell. The furnace has chromel wire heating elements with automatic temperature con...

A new electrolytic method for the deposition of adherent coatings of titanium on steel cathodes is described. The procedure involves the use of fused alkali-halide baths composed of eutectic mixtures of lithium, potassium or sodium iodides, bromides, chlorides, and fluorides, with a high-frequency heated cathode and a soluble titanium anode. The bath composed of KI-KF performed best and deposited a very smooth and uniform titanium coating. Conversely, the bath composed of KI-NaI and TiL (2 to 5%) yielded dendritic Ti and is therefore considered more suitable for an electrorefining process. Equipment and operating conditions are described and the microstructure of the coating produced is reported. A series of decomposition voltage curves is included and discussed, and the mechanism of the electrolytic reactions is studied in detail.A complete literature survey of the electrodeposition of titanium from molten salts has been published recently by Steinberg (1). Ti diffusion coatings were obtained by Straumanis, et al. (2, 3) from fused baths containing dispersed Ti crystals or Ti salts. Much remains to be investigated, however, on the deposition of uniform and strongly adherent coatings of Ti.The present work deals with an electroplating method involving the use of an induction-heated cathode and a soluble Ti anode in fused salt baths. The induction-heated cathode acts at the same time as a heating element to maintain the bath in a molten state. In this manner, the cathode is at a temperature appreciably higher than the surroundings. In fact, the anodic zone, far removed from the cathode area, may be kept much colder. This provides, therefore, means to control the rate of solution of the anode as well as volatilization losses and secondary reactions. The skin effect due to induction current creates a maximum temperature zone on the very surface of the cathode, speeding up degassing and facilitating diffusion of the deposited Ti. Furthermore, the electrolysis may be carried out in a Pyrex or transparent quartz cell which makes it convenient to see directly the phenomena taking place.

Der Mechanismus des Phosphatierungsvorganges bei Stahl wird schematisch dargestellt.