The effect of electroless Ni-P interlayer on corrosion behavior of TiN-coated austempered ductile iron

► TiN-coated austempered ductile iron (ADI) had an electroless Ni-P interlayer. ► The duplex surface treatments did not deteriorate the microstructure of ADI. ► 25 μm Ni-P interlayer efficiently raised corrosion resistance of TiN-coated ADI.