Surface treatment

A surface treatment is a mechanical, chemical, electrochemical operation or physics which results in to modify the aspect or the function of the surface of materials in order to adapt it to conditions of use given. The surface treatments play an eminent role in the field of the Tribologie (see treatments anti-wear).

Mechanical treatments

Metal coatings

Deposit by wet process

Deposit by dry roads

  • thermal Projection
  • Vapor phase
  • energy Beams
  • metal Recharging
  • Application of metal sheets: Gilding, silvering, coppering with the sheet.

Deposit by thermal way

  • Tinning
  • Gilding and silvering with mercury
  • Immersion out of molten metal

Treatments of conversion

Thermochemical treatments of diffusion

  • Diffusion of nonmetal elements Carbonitriding (of which the Cementing and the Nitruration are particular cases), Boruration, Sulfuration S, Bleuissage.
  • Diffusion of metal elements (Chromizing, Alumination)

Treatments by structure transformation

  • thermal Way (fusion, case Hardening S, annealing, income)
  • mechanical Way (Shot-blasting, Rolling)

Organic and organomineral treatments

Others

  • Anodisation lasts
  • Sulfinuzation
  • Zingage

Industrial context

The operations of surface treatments are carried out nowadays by a multitude of small companies sub-contracting for the account of great industry groups in the fields of the car, of the “white products”, aerospace…

This induced context of the generally painful work conditions and the very modest wages. The exposure to the vapors various acids used (acid sulphuric, hydrochloric, hydrocyanic, hydrofluoric…) present of serious dangers to health, and the security measures works about it in the small companies of the sector are generally insufficient (cf Factory inspectorate).

The clients true themselves thus, inter alia, of the responsibilities which would be theirs in the event of accidental pollution or industrial accident.

There exists a trade union of the surface treatments (D.Thery, acting general of the SATS).

The workshops of surface treatments are in agreement with the industrial legislation as well as all the industrial companies. They use processes which are present in the workshops of the large clients. The trade union of the surface treatments signed with CRAM agreements of constant improvement which exceed the industrial legislation. The accidentology, according to the ministerial official sources, in the workshops of surface treatments is not related on the use of the chemicals but mainly to the handling of the parts.

See too

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