The coating of Ni-P/Ni-Cu-P on the surface of Kevlar fiber was achieved by electroless plating. The surface appearance and composition of original sample

coarsened sample

plated sample and spalled coating were investigated and compared by means of SEM

EDS and XRD.In addition

the formation mechanism and spalling reason of the coating was studied.The results showed that the Kevlar fiber specific surface area

hydrophilicity and activity increased after chemical pretreatment.After chemical Ni-P/Ni-Cu-P plating

the content of Ni in Ni-P coating decreased

however

the content of P increased

Ni was transformed into Ni3P and a little Cu was discovered in Ni-P coating.The atomic proportions of Ni

Cu

P in overall coating were 8.54:3.66:5.59

the phase of the coating mostly consisted of Cu

Cu3P and Ni3P.Because the stress of coating distributed unequally and P gathered partly in Ni-P/Ni-Cu-P phase interface

the interface bonding strength was weakened and local stress concentration occurred

which appeared to be the reason for spalling of the coating.The chemical Cu plating relied on the catalytic action of nickel ions

which helped deposition of copper ions to form the coating.