Studies On The Wear-resistant, High Temperature Polyphenylenc Sulfide Composite Coating

In this paper, the polyphenylene sulfide was the basical film foemation,in whichthe two kinds of addition systems were the copper oxide produced by in-situ reactionand the nano-CaCO₃modified by organic. The polyphenylene sulfide coating withhigh temperature resistant and wear-resisting was optimized by the different formula,coating technics and performance testing. The effects of different metal surfacetreatment methods, TiO₂contents, curing time and curing temperature on the bondingstrength of the bottom layer were investigated. The addition’s composition in thecoating and crystallinity of the coating were analyzed by XRD. The variation ofmolecular groups after PPS been cross-linkinged were analyzed by FIR and thecross-linking mechanism was analyzed when the coating was solidified. Thethermostability and heat decomposed temperature of the coating was analyzed byDTA. The tribological property of the coating was tested under dry friction conditionand water lubrication condition. The friction and wear mechanism was analyzed bySEM. The main conclusions are as follows:（1） Coating and substrate were combined strongly when the subbing was filledwith15wt.%TiO₂and metal substrate surface was acid-washed and silane treated.Theadhesive strength is42MPa.（2） XRD analysis showed that diffraction maximum of the coating wassignificant lower after the coating had been cross-linked, solidified and quenched andPPS was transformed into non-crystallizable polymer. The crystallinity decreasementof PPS coating is advantages for the enhancement of its toughness.（3） FIR analysis showed that the major structure of molecular chain in the curingPPS was not changed. The sulfur atom was oxidized, including that—S—wasoxidized into—SO—or—SO₂—. The cross linkage between the coating wasmainly in the benzene ring, of which hydrogen atom was oxidized into aryloxide.（4） The in-situ reaction is run between CuSO₄and NaOH, whose product isCu（OH）₂in the investment precoat. Cu（OH）₂is then dehydrated to produce CuO,which realized the homodisperse of inorganic particles in the emulsion. XRD atlasshowed the in-situ reaction product is CuO.（5） The tribological performance of CuO/PPS/PTFE composite coating wasapparently better than pure PPS coating. The friction coefficient was decreased withthe increase of CuO content. The abrasion loss was firstly increased and then decreased, the abrasion loss of PPS coating was decreased to1/3when the CuOcontent was1.5%.（6） The tribological performance of PPS/Nano-CaCO₃composite coating underwater lubrication condition was much better than dry friction. Both the frictioncoefficient and abrasion loss were decreased to1/3of that tested under waterlubrication with compared todry friction. The friction coefficient was decreased by25%and wear rate by32%under dry friction condition with the addion of3%Nano-CaCO₃.