联用次亚磷酸钠和硼氢化钠两种还原剂 ,从酸性镀液中沉积出不同硼含量的Ni_P_B镀层 ,并用原子力显微镜、X_射线衍射、透射电镜、动电位扫描等实验技术对其镀态结构及性能进行了表征。实验表明 ,镀液中硼氢化钠含量对沉积速度影响不大 ,但能显著影响镀层的化学组成。硼的共沉积使镍晶格点阵产生扭变 ,导致镀层晶粒增大 ,表面粗糙 ,颗粒分布不均匀 ,并使镀层由非晶态向微晶结构转变 ,且微晶成分随镀层中硼含量的增加而增多。Ni_P_B镀层的硬度随镀层中硼含量的增加而增大 ,热处理能显著提高镀层的硬度 ,且服从沉淀硬化机理。在 3.5wt%NaCl和 40wt%NaOH两种介质中 ,Ni_P_B合金的耐腐蚀能力优于Ni_P合金。镀层中硼含量越高 ,其耐腐蚀能力越强。
Acknowledgments The authors gratefully acknowledge Professor B.W.Mao for use of AFM facilities at her laboratory. We would also like to thank J.Tang for assistance with AFM measurements.
[1] VanGoolAP ,BodenPJandHarrisSJ.Corrosionbehaviourofsomeelectrolessnickel_phosphoruscoatings[J].Trans.IMF ,1987,6 5 :10 8.
[2 ] ZhangYZ ,WuYYandYaoM .Characterizationofelectrolessnickelwithlowphosphorus[J].JournalofMaterialsScienceLetters,1998,17:37.
[3] SampathKPandKesavanNP .StructuraltransformationsinelectrolessNi_P_Bdeposits[J].Plat.Surf.Finish .,1994,5 :96 .
[4 ] AbdSS ,ShaffeiM ,IbiariNetal.Effectofadditivesonplatingrateandbathstabilityofelectrolessdeposi tionofnickel_phosphorus_borononaluminum[J].MetalFinishing ,1996 ,12 :2 9.
[5 ] TalaatEA ,HassibAM ,MorsyMSetal.AutocatalyticalkalineNi_P_Bplatingbaths[J].MetalFinishing ,1991,7:7.
[6 ] TakayukiH ,MasayukiT ,KunimasaIetal.Tappingmodeatomicforcemicroscopyanalysisofthegrowthprocessofelectrolessnickel_phosphorusfilmsonnonconductingsurfaces[J].J .Electrochem .Soc.,1997,144 :412 3.
[7] HwangBJandLinSH .Reactionmechanismofelectrolessdeposition :observationsofmorphologyevolutionduringnucleationandgrowthviatappingmodeAFM[J].J.Electrochem .Soc .,1995 ,142 :3749.
[8] MitalCKandShrivastavaPB .Electrolessnickel_phosphorus_boronalloycoatings[J].MetalFinishing ,1986 ,10 :6 7.
[9] MartyakNM ,WettererS ,HarrisonLetal.Structureofelectrolessnickelcoatings[J].Plat.Surf.Finish .,1993,6 :6 0 .
[10 ] DuncanRN .Themetallurgicalstructureofelectrolessnickeldeposits:effectoncoatingproperties[J].Plat.Surf.Finish .,1996 ,11:6 5 .
[11] DiegleRB ,SorensenNRandNelsonGC .DissolutionofglassyNi_PalloysinH2 SO4 andHClelectrolytes[J].J.Electrochem .Soc .,1986 ,133:176 9.
[12 ] FlisJandDuquetteDJ.Effectofphosphorusonanodicdissolutionandpassivationofnickelinnearneutralsolutions[J].Corrosion ,1985 ,41:70 0 .
[13] CarbajalJLandWhiteRE .ElectrochemicalproductionandcorrosiontestingofamorphousNi_P[J].J .Electrochem .Soc.,1988,135 :2 95 2 .
[14] LoPH ,TsaiWT ,LeeJTetal.TheelectrochemicalbehaviorofelectrolessplatedNi_Palloysinconcen tratedNaOHsolution[J].J.Electrochem .Soc.,1995 ,142 :91.