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Metal / Corrosion - Crevice Corrosio

Type of Surface Change

  • Since crevice corrosion is a locally accelerated type of corrosion, it leads to corrosion deposits only in the crevice area (e.g. in the joint crevice of the two halves of a pair of forceps, in joint gaps or in pressed-in or screwed-in working ends in the case of probes, for example).
  • Frequently, non-removed residues (particularly organic ones) are mistaken for crevice corrosion.

Origin & Causes        

  • Crevice corrosion tends to occur in gaps of critical width if the prevailing ambient conditions are favorable (e.g. insufficient drying). Under such conditions, the passive layer is vulnerable to attack because it can no longer regenerate when the oxygen supply is blocked or impeded. As a result, rust formation will occur as soon as humidity comes into play (particularly at higher salt concentrations), with the rust working its way out of the gap or crevice.
  • Crevice corrosion can occur also in the gaps between metal and other materials.

Treatment Recommendations        

  • Treat affected instruments in accordance with the manufacturer's directions.
  • Mechanical treatment (reworking) of the instrument by the manufacturer or an authorized and thus qualified repair service.

Preventive Measures        

  • The single most important measure for preventing this type of corrosion is the sufficient drying of close joint gaps.
  • Use rinsing water with a low salt content (recommended: fully demineralized water).

Risk Assessment

Spread of rust to other instruments is usually excluded. In severe cases, however, the rust might affect intact instruments and cause consequential damage there as well (see also "extraneous and film rust").