Passivation â?? Getting Maximum Performance from Stainless Steel

Although the beauty of stainless steel is that you don't generally need to put any type of coating on it, when you are using this material in any sort of industrial process, it may be prone to free iron contamination. With a process known as passivation , you can remove these iron compounds with the use of a chemical dissolution, such as a treatment with acid solution. This helps enhance the performance level of stainless steel or other materials, preventing premature corrosion or deterioration and increasing the material's lifespan.

Passivation is a combination of a cleaning process, because it removes the iron compounds, and is also a protective coating at the same time because it prevents the buildup of any further iron compounds or oxidation. This process begins with a thorough cleaning of the material that is being treated, which is capable of removing coolants, grease, oil, or any other residues that are left behind on the surface of the steel. When steel is used in fabricating machines, they can leave behind their mark in minute amounts. Any type of cleaning can be used to start this process, whether it is soaking the steel in an alkaline solution, or cleaning it with solvents that are specifically designed for this purpose.

After these various residues are removed, the next step to passivate the steel is to place it into a passivating solution. These are usually based on nitric acid, although there are alternative options including citric acid for a more environmentally friendly solution. These will vary in terms of temperature, the concentration of the nitric acid or other passivating agent, and the time that the steel must spend in this immersion. In general the period will range for anywhere from 20 minutes to an hour, depending on the concentration. There are many different variables to include in this length of time.

Another factor to consider when passivating stainless steel is the type of steel that you are using. Be sure to consult with an expert in this field if you have no experience with preparing industrial materials or using acid baths, because if you use the wrong solution or leave the steel in for too long of a time period, there could be negative results. This could include the entire piece of steel dissolving if you are not careful. For this reason, it's always important to get professional guidance or send off your mechanical parts for passivation by professional services.