镁合金纳米tiolt2gtnip复合镀层的制备与性能

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1、镁合金纳米Ti02／Ni．P复合镀层的制备与性能摘要镁合金已得到日益广泛的应用，其防护技术已经成为难点和热点．本文在镁合金Ni—P合金镀液的基础上，通过添加纳米Ti02颗粒和表面活性剂，在超声波振荡作用下，制备了纳米复合镀液，进而制备了镁合金纳米Ti02／Ni—P复合镀层。通过正交试验法，对影响镀层性能的镀液中纳米Ti02颗粒含量、表面活性剂浓度、pH值、镀液温度四个因素进行分析．另外还研究了还原剂、稳定剂、络合剂、pH值、温度对沉积速度的影响，以及表面活性剂种类、表面活性剂浓度、温度、纳米颗粒

2、浓度对镀层硬度的影响，得出了优化的施镀工艺．本文还对比了镁合金纳米复合镀层和普通合金镀层的性能，对比发现两种镀层都与基体结合良好；纳米复合镀层的显微硬度和耐磨性能和普通镍基镀层相比有较大的提高，表明纳米粒子对镀层有强化作用。复合镀层和合金镀层的耐腐蚀性都比基底镁合金高得多。动电位扫描以及在多种腐蚀介质中的耐蚀性试验结果表明纳米复合镀可能提高镍磷合金镀层的耐蚀性。对复合镀层进行锉削及弯曲试验，表面未见鼓泡、起皮、脱落及裂痕等，表明镀层与基体结合状况良好．关键词：镁合金；化学镀；镍磷合金；复合镀层；

3、纳米氧化钛IVPREnU认TIoNANDPRoPERTIESoFTHECoMPoSITECoATINGoFNANO-Ti02／Ni-PALLOYoNⅣIAGNESIUMALLoYABSTRACTMagnesiumalloyhasalreadybeenusedwiderandwider．Itsprotectiontechnologyhasbecomeahardtaskandahotspot．Inthisthesisthecompositeelectrolytewithnanoparticlesis

4、preparedbyaddingTi02particlesandsurfactantintotheNi-Palloyelectrolyteofmagnesiumalloyundertheeffectofultrasonicwavevibration．Fourfactorsofthecontentofnanoparticlesintheelectrolyte,thecontentofsurfactantintheelectrolyte,pHvalueandtemperatureoftheelect

5、rolytewhichaffecttheperfommceofcompositecoatingsareoptimizedintheorthogonalexperiments．Influencesofreductant,stabilizer,complexingagrent、pHvalueandtemperatureondepositionratearcstudied,andtheeffectsofvarioussurfactants，bathcontentofsurfactants，temper

6、atureandbathcontentofnanoparticlesonthehardnessofthecomingalealsoinvestigated．Anoptimumtechniquehasbeenobtained．TheperformancesofcompositecoatingsarealsocomparedwiththoseoftheNi—Palloycomings．Theresultsindicatethatbothofthecoatingscombineverywellwith

7、thesubstrate，andthemicrohardnessandwearresistanceofnanocompositecoatingsarehigherthanthoseofNi-Pahoycoatings．VThereforeitcanbededucedthatnanoparticlescanstrengthenthecoatings．Thecorrosionresistancesofboththecompositecoatingandthealloycoatingaremuchhi

8、gherthanthatofthesubstratemagnesiumalloy．DynamicpotentialscanningandtheerosionresistancesinvariouserosivemediumsshowthatnanocompositecoatingcanpromotethecorrosionresistanceoftheNi—Palloy．coating．Nobubbling,corrugation,abscissionandcrackingarefoundthr