Research On ZrO₂ Ceramic/Febased Amorphous Composite Coating By Plasma Spraying

In this paper,Fe-based amorphous coating was prepared by plasma spraying,By studying the preparation technology and properties of Fe-based amorphous coating,choose the best spraying power.and based on this preparation technology,a novel of gas multiple-tunnel plasma spraying technology was adopted to fabricate composite coatings,getting two different component and dense composite coatings,the properties of ceramic-amorphous composite coatings which adding different content of ZrO₂（hardness,bonding strength,scratch resistance,wear resistance and corrosion resistance）were analyzed and discussed.Studies had shown that:1)Fe-based amorphous coating can be successfully prepared by plasma spraying,which fine distribution is uniform,no crystal phase or oxide phase.The increase of spraying power,the Fe-based amorphous coating density and hardness increase.But when the spraying power was 40 KW,there was crystal phase exist.So the best of spraying power was 35 KW.2)The different addition of ZrO₂ which ZrO₂ ceramic/Fe-based amorphous composite coatings can be successfully prepared by the novel of gas multiple-tunnel plasma spraying technology about double sends.Ceramic-amorphous composite coatings only consist of Fe-based amorphous phase and ZrO₂ ceramic phase.And proportion of two phases in the ceramic-amorphous composite coatings can be realized regulation.With the increase of ZrO₂ content,the porosity of ceramics-amorphous composite coatings increased,the hardness firstly increased and then decreased.When the addition of ZrO₂ content was20wt.%,the porosity of ceramics-amorphous reached the minimum,the hardness,the scratch resistance and the bonding strength reached the maximum.3)Friction and wear experiment test results of ZrO₂ ceramic/Fe-based amorphous composite coatings indicate that the addition of ZrO₂ improves the wear resistance.However,the wear rate of the ceramics-amorphous composite coatings was not linear related to the fraction of ZrO₂.There was a transformation form toughness to brittleness with the increase of ZrO₂ in the ceramics-amorphous composite coatings.Therefore,the wear failure mechanism of the ceramics-amorphous composite coatings was changed form abrasive wear to fatigue wear.With the increase of load,the friction coefficient of ceramics-amorphous composite coatings were lower than Fe-based coating always.4)In the process of corrosion of Fe-based amorphous coating and ceramics-amorphous composite coatings,the potential of two kinds of coatings were moved negatively.When the addition of ZrO₂ content was 50wt.%,the potential values of ceramics-amorphous composite coating was higher and the corrosion current was smaller indifferent corrosive environment,such as 3.5%NaCl solution,0.5 mol/LH2SO4 solution,NaOH solution.This indicates the corrosion resistance of the addition of ZrO₂ which50wt.%ceramics-amorphous composite coating was superior than other coatings.