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Metal / Corrosion - Fretting Corrosion

Type of Surface Change

Brown stains/discolorations or rust formation around an area that has been chafed blank.

Origin & Causes       

Insufficient lubrication leads to corrosion of the metallic friction surfaces (or instrument parts) that move relative to each other (especially in locks/joints and sliding paths of, for example, punching instruments). Microabrasion occurs in such cases, which destroys the passive layer. In these sensitized places, humidity and deposits (e.g. blood residues) can easily accumulate - a process that usually leads to corrosion.

Treatment Recommendations       

  • Discard defective instruments or have them repaired where possible.
  • Regrinding and/or polishing can usually repair corrosion damage.
    Note: Repeated reworking affects the handling/controllability and thus the functionality of the instrument, making it unusable.

Preventive Measures         

  • Proper instrument care and servicing: Apply a lubricant to the instrument in the joint area prior to performing the functional check.
  • Allow the instruments to cool down to room temperature (danger of metal abrasion).
  • Manually apply the lubricant directly to the joint area (using drops or spray).
  • Distribute the lubricant uniformly in the joint by opening and closing the instrument several times.

Requirements for lubricants suitable for instrument care:
Lubricant basis: e.g. liquid paraffin / white oil (paraffin oil).The lubricant used must conform to the currently valid pharmacopoeia and must be physiologically safe as specified by the German Pharmacopoeia (DAB) and Article 31 of the LMBG (German Food and Commodities Act) (or corresponding national regulations). Moreover, it must be vapor-permeable/sterilizable. "Gumming" of the joints due to an accumulative effect must be prevented.

Risk Assessment       

  • Warning: Do not use lubricants with rubber and latex items; leads to swelling and surface destruction.
  • Impairs or completely destroys the instrument's functionality. Fretting corrosion may lead to pitting.