Composition for electrolytic descaling of titanium and its alloys

Claim 2

An additive as in claim 1 wherein the hydrofluoric-acid bearing compound is selected from the group of fluo acids including hydrofluoric, fluoboric, and fluosilicic acids.

Claim 3

A non-aqueous electrolytic bath composition for descaling an article formed of titanium and its alloys comprising glacial acetic acid, concentrated sulfuric acid dissolved in the acetic acid, and hydrofluoric acid (48-50), said acetic acid comprising from 55 to 70 percent by volume of the bath, said sulfuric acid comprising from 20-30 percent by volume of the bath, and the hydrofluoric acid being 48 to 50 percent acid and comprising 10 to 15 percent by volume of the bath.

Claim 4

A composition as in claim 4 and further comprising a non-reactive inhibitor for inhibiting attack of the hydrofluoric acid on the titanium article when current flow in the bath is discontinued, said inhibitor consisting of a mixture of amides and an acetylenic alcohol, said amides containing the general structure in which the alkyl group approximates the C12 14 range and wherein the amides and the acetylenic alcohol respectively are 65 and 35 percent by volume of the inhibitor, said inhibitor comprising from 0.3 to 0.5 percent by volume of the bath.

Claim 5

A composition as in claim 4 and further comprising an anionic wetting agent operable in the acid bath and having the form of a dodecylated oxydibenzene disulfonate sodium salt, said wetting agent comprising from 0.2 to 0.3 percent by volume of the bath.

Claim 6

A composition as in claim 4 and further comprising a layer of paraffin oil on the acidic bath to prevent loss by vaporization of the hydrofluoric acid and to contain fumes from the acetic acid.

Claim 7

A non-aqueous electrolytic bath composition for descaling an article formed of titanium and its alloys and consisting of the following constituents and proportions thereof by volume of the bath: Acetic Acid (Glacial) 55 - 70% Sulfuric Acid (Concentrated) 20 30% Hydrofluoric Acid (48 - 50%) 10 - 15% Inhibitor (Amide-acetylenic alcohol mixture) 0.3 - 0.5% Wetting Agent (Anionic surfactant) 0.2 - 0.3% said inhibitor consisting of a mixture of amides and an acetylenic alcohol, said amides containing the general structure in which the alkyl group approximates the C12 14 range and wherein thE amides and the acetylenic alcohol respectively are 65 and 35 percent by volume of the inhibitor, said wetting agent being an anionic surfactant in the form of a dodecylated oxydibenzene disulfonate sodium salt, the sulfuric acid being dissolved in the acetic acid.

Claim 8

A non-aqueous electrolytic bath for descaling an article formed of titanium and its alloys wherein the article is the anode in the bath, said bath consisting essentially of a hydrofluoric acid bearing compound providing an acidic attack ion in the bath which in response to current flow attacks and penetrates the scale on the article to forcibly release its attachment to the substrate metal, a buffering agent which acts as a dehydrating agent for picking up water from hydrofluoric acid formed in the bath to deionize the same and prevent attack on the titanium, and a non-aqueous liquid organic acid as the carrier in the bath, said hydrofluoric acid bearing compound being in amount equivalent to 10 to 15 percent hydrofluoric acid by volume of the bath, said carrier being in amount equivalent to 55 to 70 percent glacial acetic acid by volume of the bath, and said buffering agent being in amount equal to 20 to 30 percent concentrated sulfuric acid by volume of the bath.