Corrosion resistance of Ni-P amorphous composite coating inthe environment containing H₂S/ CO₂

A multilayer amorphous Ni-P composite coating with a potential difference above 160mV was preparedin the same bath by varying the temperature , p H value and elect ric field alternately. The anti-corrosion behavior ofthe composite coating was studied in the environment with H₂S and CO₂ , and the result s show that the terraceamorphous Ni-P composite coating performed well in corrosion-resistance in the environment with H₂S and CO₂ .An even corrosive film formed on the surface of the composite terrace coating af ter 100h. Corrosive cracks appearedon the composite coating’s surface af ter 300h , and the cracks expanded along the parallel direction of the base. Theenrichment of phosphorus occurred in the places where the elect rodeposited coating was deprived. The corrosion results indicated that this multilayer Ni2P coating of 12μm thickness possessed better anti-corrosion properties thanthe plain elect roless coating of 25μm.