Corrosion Resistance Test

For stainless steel surgical instruments, there are many tests which can be done,but the most important are the following:-

i- Copper Sulphate Test:
   During the process of manufacturing, it is very likely that certain free iron particles are left on the surface, which  are not visible ordinarily. This test is carried out to confirm the presence or otherwise of such particles. This test is done in a solution of CUSO and HSO at 15 C for 6 minutes. The instruments are thoroughly cleaned with soap and water and then rinsed in hot water. The instruments are then immersed in CUSO solution which   reacts with any Free Iron  on the surface of the instruments, and copper deposits on them. This Cu.deposit is removed by wet piece of cotton cloth. There shall be no plating at the periphery or drops of solution or at soldered or brazed junctions or dulling of polished surface caused by coppersulphate solution shall be disregarded. A slight plating of copper in small part of looks, ratchets and serrations of jaws shall also be discarded.

ii- Boil Test:

 The boil test requires immersing the instruments, in boiling distilled water. The instruments are cleaned with soapier water and thoroughly rinsed in hot water before putting in boiling water. The instruments are heated in boiling water for 30 minutes and let to stay in the water for 2 hours. These are removed and kept for 2 hours in open air prior to examination. The instruments are wiped with a dry cloth and inspected for visible sign of corrosion. Any blemish, not removed by vigorous hand rubbing with a cloth and shall be considered evidence of corrosion.