As you can see from the photos, before the treatment, the surface had a significant presence of iron oxides. Why does this happen even though the autoclave was originally passivated and there are no external iron contaminants?
There are two answers: first, over time, the surface is “stressed” by the aggressive environment inside the autoclave. This involves high temperatures and pure steam created from water with very low conductivity and a pH around 6.
This mix of factors severely tests the alloy over time, and iron oxides may start to appear on the surface, indicating that the passive layer has been corrupted.
The second cause is the friction of the carts or trays on the guides inside the autoclave. This continuous metal-to-metal friction removes the passive layer, which cannot spontaneously reform due to the aggressive environment described above.
Over time, as can be seen from the photos before the chemical treatment that we will describe later, the condition of this autoclave gradually worsened, causing problems with the final product being sterilized inside it.
Repassivation of an Autoclave: BAMA’s Intervention to Restore Optimal Surface Conditions
At this point, BAMA was called for a technical evaluation and, after identifying the problem, proposed a localized intervention with a specifically formulated product, BAMA ECODEC!
BAMA ECODEC is a citric-based product formulated to remove surface oxides and restore the passivation of stainless steel.
Our operators, equipped with the specific PPE for this type of chemical product, intervened by spraying BAMA ECODEC on the surface and then, using tissue paper and manual rubbing, completely removed all the present oxide.
The rinsing phase following the application of the product is crucial. It is essential to ensure that all residual acidity has been completely removed. It is useful for this purpose to conduct pH and conductivity tests on the final rinse water.
Finally, as shown in the images, the surface is now completely decontaminated, clean, back to its original color, with no presence of oxide spots or yellow halos.
BAMA’s quality control personnel then conducted passivation tests, which yielded compliant results.
