Acid etching bath for titanium alloy of components
AssigneeSociete Nationale d'Etude et de Construction de Moteurs d'Aviation "S.N.E.C.M.A."
InventorsClaude G. G. Gondel, Christian P. H. G. Hennebelle
Life of this patent
Estimating the term…
Abstract
An acid etching bath for activating titanium alloy components, especially turbo-machine blades and discs, before macrographic anodic oxidation in an electrochemical etching process, known as the "blue-etch" process, for the non-destructive checking of the components, comprises 75.+-.5 ml/1 of sulphuric acid, from 11 to 15 g/1 of sodium fluoride, and water as the balance.
Claims4
An acid etching bath comprising:
- (i) 75.+-.5 ml/l of sulfuric acid (H.sub.2 SO.sub.4) having a density of about 1.83;
- (ii) 11-15 g/l of sodium fluoride (NaF), and
- (iii) water.
An electro-chemical etching process for titanium alloy components comprising, in succession, the steps of:
- (i) degreasing;
- (ii) rinsing;
- (iii) activation by acid etching;
- (iv) rinsing;
- (v) anodic oxidation in a trisodium phosphate bath;
- (vi) rinsing;
- and
- (vii) development by etching in a nitrohydrofluoric bath,
- wherein said activation step is carried out in an acid etching bath comprising:
- (i) 75.+-.5 ml/l of sulfuric acid (H.sub.2 SO.sub.4) having a density of about 1.83;
- (ii) 11-15 g/l of sodium fluoride (NaF), and
- (iii) water;
- wherein said acid etching bath is periodically recharged by adding from 5 to 10 ml/l of sulfuric acid and from 3 to 4 g/l of sodium fluoride.
An electro-chemical etching process for titanium alloy components comprising, in succession, the steps of:
- (i) degreasing;
- (ii) rinsing;
- (iii) activation by acid etching;
- (iv) rinsing;
- (v) anodic oxidation in a trisodium phosphate bath;
- (vi) rinsing;
- and
- (vii) development by etching in a nitrohydrofluoric bath,
- wherein said activation step is carried out in an acid etching bath comprising:
- (i) 75.+-.5 ml/l of sulfuric acid (H.sub.2 SO.sub.4) having a density of about 1.83;
- (ii) 11-15 g/l of sodium fluoride (NaF), and
- (iii) water;
- at a temperature between 16.degree.-25.degree. C., and
- wherein said acid etching bath is agitated with compressed air.
Dependencies are inferred from the claim text.