SU876800A1 - Melt for electrolytic titanium-coating - Google Patents

Description

(54) MELT FOR ELECTROLYTIC APPLICATION The invention relates to the application of coatings of refractory metals from melts, in particular titanium coatings, and can be used in npHeopocrpioenia, mechanical engineering and other industries. A melt is known for electrolytic deposition of titanium coatings containing a low-melting eutectic mixture of metal chlorides selected from the group consisting of alkali and alkaline earth ala. and 5-10% lower titanium chloride Cl}. The disadvantage of this design is the relatively high temperature of the electrolit process (38 ° 40 ° C), which does not allow to obtain titanium coatings on low-melting metals. Closest to the one proposed is an electrolytic melt. titanium coatings containing a mixture of aluminum chloride and titanium trichloride. The electrolyte is produced by introducing titanium tetrachloride into molten gas. TITANIUM COATINGS Research Institute and the melt of aluminum chloride. Titanium trichloride is formed in the bath, which, mixed with aluminum chloride, serves as an electrolyte for the application of titanium coatings. Process Electrodeposition of titanium is carried out at a temperature of 20 ° C and a cathode current density of 24 A / dm with a current efficiency of 85-9 O% 2. The main disadvantages of this electrolyte are the complexity of the coating technology arising from the need for equipment sealing, difficulty in controlling the composition of the electrolyte due to the volatility of aluminum chloride, as well as the relatively low rate of coating due to low current densities. The purpose of the invention is to simplify the technology and expand the range of current densities for the deposition of titanium coatings. The goal is achieved by the fact that the melt containing a low-melting component and titanium hioride additionally contains ammonium chloride, and as a low-melting component and rio-titanium hls, a mixture of carbamio-aaetamda and chlind titanium, respectively, with the following component content, wt.%:

Urea36,4-54,6

Acetamits36,4-54,6

Ammonium chloride 1-3

Titanium tetrachloride4-7

The melt is prepared by mixing the components in calculated amounts and blending the mixture to the electrolysis temperature. The coating process is carried out in the temperature range 95120, C, current density range 28 using titanium anodes. The use of the melt makes it possible to apply light gray titanium coatings up to 12 µm thick, with a hardness of 29O-345 kg / mm with a speed of 0.15O, 48 µm / min in the range of current densities of 2-8 A / dm on steel substrates,. zinc, lead and tin. The electrolyte melt is not hygroscopic and does not require protection with an inert atmosphere.

The optimum temperature range is determined from the conditions for maintaining a sufficiently high rate of coating at a lower limit of temperature and stability of the electrolyte in composition for the upper limit. This also determines the content of carbamide and acetamide in the melt of electorlite. Lowering the temperature below 95 ° C reduces the coating rate of the ed by reducing the electrical conductivity of the melt and raising the temperature to 12 ° C reduces the stability of the electrolyte due to volatilization of titanium tetrachloride and ammonium chloride. The introduction of ammonium chloride allows

to increase the electrical conductivity of the electrolyte and at the same time its stability by preventing the thermal decomposition of urea, which results in the formation of 1mmonium cyanag and biuret, leading to thickening of the melt. The melt, which does not contain ammonium chloride, thickens after 15-2O hours of work, whereas the proposed electrolyte requires an adjustment for ammonium chloride only after 6O hours of work.

Examples of deposition of titanium coatings are given in the table.

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Claims (2)

I I I I As a viano of these valuables, the use of a proprietary melt makes it possible to significantly simplify the technology for producing titanium coatings on low-melting metals and steel under production conditions. This allows the invention to be widely used in industry. Claims of the Invention A melt of pl electrolytic deposition of titanium coatings containing a low-melting component and titanium chloride. This is what, in order to simplify the technology and expand the current density range, it contains 8 O but contains ammonium chloride, and a mixture of carbamine-acetamide and titanium tetrachloride as a low-melting component and titanium chloride I, respectively, with the following content of components, wt.%: Urea 36,4-54,6 Acetamide 36,4-54,6 Ammonium chloride 1 s Titanium tetrachloride 4-7 Sources of information taken into account during the examination 1. USSR Author's Certificate No. 379674, cl. C 25 D 3/66, 1973. 2. Japanese patent number 29362, l. 12 A 212, published. 1971.