Richard L a écrit:tiens, en passant, l'alu sa s'anodise aussi ou quand l'alu est anodisé il est en fait peint ?
ilium a écrit:Révise tes cours Léon: le titane ne contient pas d'alu et est un élément à part entière. Sauf erreur de ma part, le titane pur s'anodise et ce sont donc 2 réactions chimiques similaires mais sur des éléments différents... bon sur ce dernier point, faudrait que je révise.
L'ANODISATION SULFURIQUE DU TITANE
PROPRIETES ET ASPECT :
Comparativement aux anodisations sulfuriques réalisées sur les alliages d'aluminium, la structure du film obtenu sur le titane et ses alliages est différente.
Il s'agit d'un film mince compact, non poreux qui joure le rôle de barrière.
Dans la plupart des cas on réalise ce traitement sur du titane par type T40, T60 ou sur du titane allié TA6V.
L'anodisation du titane et de ses alliages peut supporter un post-traitement tels que la peinture ou le vernis à base de molybdène, téflon qui amélioreront les propriétés de frottements.
* L'épaisseur obtenue varie entre 20 et 600 Angstroems.
* La couleur obtenue dépend de l'épaisseur d'oxyde déposée:
o Couleur argent pour 25 Angstroems
o Couleur or pour 250 Angstroems.
o Couleur bleue pour 600 Angstroems.
Titanium and Titanium Alloys – The Anodising Process and Its Effects
Background
As a surface treatment, anodising, which thickens the natural titanium oxide film confers only a minimum improvement to wear resistance. Where components are not subjected to continual wear, which will cause the layer to be removed, anodising provides a simple cost-effective solution.
Galling can be significantly reduced for example on threaded components by acid anodising in conjunction with shot peening and dry film lubricant.
The anodic film also serves to reduce the inward diffusion of oxygen at elevated temperature and of hydrogen under conditions of cathodic charging.
Thicker oxide films able to withstand relatively higher loading are produced by alkaline anodising processes. The deposition of low frictional co-efficient polymers simultaneously with the growth of the anodic film provides both surface hardness and optimum corrosion resistance and lubricity.
Many electrolytes are effective for the basic anodising process. A sound coherent film can be produced in a solution of 80% phosphoric acid and 10% sulphuric acid, with 10% water, with potential raised from 0 to 110V over 10 minutes.
Progressive thickening of the oxide film by anodising results in a surface colour change due to the refraction of light. This effect has been used imaginatively to produce paintings, ornamental jewellery and large architectural panels. Various electrolytes are suitable but 3-5% trisodium phosphate in distilled water is commonly used. Colours produced vary according to the electrolyte and the applied voltage.
Anodising has also been used as a means of removing surface iron contamination – for example as a final clean up operation on titanium fabrications. It is less effective however than a five minute pickle in a nitric/hydrofluoric acid. Traces of iron have been found to remain even after 20 minutes anodising.
Anodized titanium is used in a recent generation of dental implants. An anodized oxide layer has a thickness in the range of 500 to 1000 angstroms, much thicker than that for a naturally formed oxide layer, which has a range of 50 to 250 angstroms.[citation needed]
Titanium anodic films cannot be made thicker than about 300nm, and are therefore susceptible to mechanical damage.Standards for titanium anodizing are given by AMS 2487 and AMS 2488.
Anodizing titanium generates an array of different colors without dyes, for which it is sometimes used in art, costume jewelry, body piercing jewellery and wedding rings.The color formed is dependent on the thickness of the oxide (which is determined by the anodising voltage); it is caused by the interference of light reflecting off the oxide surface with light traveling through it and reflecting off the underlying metal surface. Titanium nitride coatings can also be formed, which have a brown or golden color and have the same wear and corrosion benefits as anodization.
ilium a écrit:J'ai pas l'habitude des rainures bleues.
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