Electrical heating arrangement used for heating corrosive liquid, especially a urea solution, in vehicle comprises heating element sealed by metallic housing coated with inorganic non-metallic layer containing boron, carbon and/or silicon

摘要

Electrical heating arrangement comprises a heating element sealed by a metallic housing (6). The housing is immersed in a liquid during operation and is coated with an inorganic non-metallic layer (19) containing boron, carbon and/or silicon or a compound containing one of these elements. Preferred Features: The layer is deposited in the gas phase, preferably by chemical vapor deposition (CVD), especially PACVD. The layer is a diamond-like carbon layer and contains polycondensed silanes or silicon oxide. The layer is less than 20 mu m, preferably less than 10 mu m. The layer is amorphous. The housing is made from aluminum or aluminum alloy.