A method is disclosed for the treatment of a powder by use of a plasma reactor under atmospheric pressure, comprising the steps of providing a reaction chamber having first and second electrodes covered with a dielectric, an upper gas exhaust means and a lower gas inlet means, feeding a fluidizing gas comprising a rare gas, a monomer gas or a mixture thereof through said gas inlet means into said chamber to agitate a powder to be treated in said chamber, concurrently removing said gas from said chamber through said gas exhaust means; and generating a glow plasma under atmospheric pressure in said chamber by applying a voltage to said first electrode and grounding said second electrode whereby said powder is provided with an anticorrosive surface treatment.