Electromagnetic Acoustic Transducers for Testing Power Station Boiler Tubes

Certain types of oxide scales on steel are known to enhance the efficiency of Electromagnetic Acoustic Transducer (EMAT) operation [1,3]. This paper presents results from the oxides which form on the boiler pipes in fossil fuel fired power stations. Two principal oxides form, firstly a thin layer of black magnetite which is covered by a thicker outer layer of reddish hematite