Material Compatibility:

Is it OK to diffuse oils in a nebulizer with metal components?
     I sometimes hear rumors in the aromatherapy industry that essential oils should not come in contact with metal. The general concern is a possible reactance between the oil and metal which may create contamination or chemical composition changes in the oil itself. Such changes are said to damage the purity or essence of the oil.
     As a design engineer, I would like to see an official report from anyone in the aromatherapy industry that has systematically conducted tests and positively qualified such claims. Without such reports, I would tend to believe that these claims are hearsay and not based on facts. Rumors often spread because they sound reasonable, but the general public can not prove otherwise.

Here is why I challenge these statements:
Many of the essential oil nebulizers offered on the market are made of metal or have metal components. Many of the nebulizers offered at Diffuser World are also made of metal and I can tell you something about their composition.

1. The Air Jet (the inside component that makes diffusion work) is made of stainless steel. The same type of material used in food processing, medical equipment and even the extraction stills / distillers at the essential oil manufacturing facilities. Obviously the contamination from stainless steel is not a problem.

2. The material used to make the diffuser body and other components is an aircraft grade 6061-T6 aluminum alloy. It is true that aluminum in its raw state is a reactive material, even in the air it will oxidize (similar to rust) and form a discoloration layer. I am sure that acidic oils directly contacting raw aluminum could become contaminated over a period of time.
     The diffusers however, are treated with a special anodizing and bright dip process that forms a hard coating of aluminum oxide (The color layer) which in itself is a totally different material than raw aluminum.
     Aluminum oxide: is the same substance they used to put in underarm deodorant. In a powdered form it would embed itself into the pores of the skin and aid in plugging the sweat glands.
     Aluminum oxide: in its pure form is sapphire.
     Aluminum oxide: is a very hard substance that resists abrasion and scratches, and is actually used in one of the three common types of sandpaper.
                Garnet: is the cheep sandpaper made of crushed stone.
                Aluminum oxide: Is much longer lasting and is usually black.
                Silicon carbide: Is the hardest and best suited for wet / dry applications.

As you can see, aluminum is not considered a dangerous material and the hard aluminum oxide layer on the diffuser surface is almost impossible to contaminate or change the chemical composition of any essential oil. It is also very resistive to abrasion and scratching.

So, given this information, until someone can provide valid and documented test results of essential oil contamination or chemical composition changes directly related to stainless steel and / or aluminum oxide, including the static dissipative characteristics and effects on competitive materials like ethylene based plastics and glass, I would be skeptical of such claims. I would not hinge my buying decisions on any of the materials stated by such rumors or hearsay. In a nutshell, I think any companies nebulizers using these 4 materials are compatible with essential oils. Any material not compatible would be obvious by the deterioration of the material through prolonged use.

Article written by Design engineer Earl V. Sevy