铌基镀铂电极的研制.pdf

36铌基镀铂电极的研制张玉萍1,鞠 鹤1,武宏让1,武志红2(1.西北有色金属研究院泰金公司,陕西 西安 710016;2.西安建筑科技大学材料科学与工程学院,陕西 西安 710055)摘 要 铂铌电极强度高,耐腐蚀,导电性好,催化活性高,广泛应用于阴极保护、电解工业、离子水制备等领域中。为此,利用正交试验法研究了通过水溶液电镀制取铂铌电极的工艺,确定了铌基镀铂的最优工艺条件为:15 g/L Pt(NH3)2(NO2)2 2H2O,100 g/L NH2OSO2H,4 g/L添加剂 L(胺类有机物),电流密度 50 150 A/m2,温度 60 80。该电镀液均镀能力良好,阴极电流效率为32%,可获得致密的 10 m厚光亮铂镀层。制得的铌铂电极性能良好。关键词 Pt/Nb电极;铌基电镀;性能中图分类号 TQ 153.2文献标识码 A文章编号 1001-1560(2006)04-0036-03收稿日期 200509170前言铂具有优良的耐蚀性、导电性和催化活性,电化学性质非常稳定,在很多电解过程中几乎都是惰性材料,但铂是贵金属,作为单一的固体电极使用成本较高。铌是一种阀性金属,其氧化膜具有可贵的“阀门”作用,即在阳极状态下不导电,而在阴极状态下可以导电。在其上电镀铂,即使镀层表面有孔隙,在通阳极电流时也不会发生腐蚀,由于孔下的基体处将自动地由其自身的氧化膜随机填充,该氧化膜耐蚀性极强 1,2。本工作对在铌基材料表面镀铂的工艺及铂铌电极性能进行了研究。1试验1.1 铌基材表面处理在退火轧制过程中铌表面会形成一层氧化膜,如果在其上直接镀铂,很容易造成铂镀层脱皮。为了得到与基体结合良好的镀层,必须对铌基表面进行活化处理,去掉其表面的氧化皮。将铌表面用丙酮除油、水洗,然后进行酸洗活化,酸洗活化液为HF(5%)+H2O(75%)+H2SO4(20%)(体积比)。铌表面酸洗活化后,用去离子水冲洗干净,立即置于镀铂液中电镀 3。1.2 电镀铂水溶液电镀铂是目前应用较广泛的镀铂工艺,它的溶液种类主要分酸性和碱性两大类,碱性镀铂溶液有以二亚硝酸二氨铂为主盐的 P盐镀铂溶液和以六羟基铂酸钾为主盐的强碱性镀铂溶液等;酸性镀铂溶液有氨基磺酸型镀铂溶液和硫酸盐 DNS镀铂溶液等。本试验选用氨基磺酸型镀铂液。1.2.1电镀工艺参数确定镀铂液含 P盐 10 g/L,氨基磺酸 100 g/L。固定电流密度为 80 A/m2,改变镀液温度,所得试验结果见表 1。再固定镀液温度为 70,改变电流密度,所得结果见表 2。表 1镀液温度对镀层性能影响温度/镀层颜色镀层和基体结合力50发黑掉灰60白好70白好80白好表 2电流密度对镀层性能影响电流密度/(A m-2)镀层颜色镀层和基体结合力20灰黑掉灰50白好150白好200白边缘掉皮由表 1、表 2可知,镀液温度取 60 80 为宜,电流密度选择 50 150 A/m2较合适。1.2.2镀液配方优选含 10 g/L P盐、100 g/L氨基磺酸的镀铂液中得到的铂镀层颜色洁白,镀层和基体结合力尚可,陕西易莱德新材料科技有限公司法人代表和技术总监-武宏让,专业生产涂层钛阳极的10 年老厂.37但得不到厚铂镀层。要想得到合格的镀层,必须加入适当的添加剂,提高溶液的均镀能力和阴极极化度。为此,进行正交试验优选。正交表考虑 3个因素:P盐浓度,氨基磺酸浓度,添加剂 L浓度,每个因素取 3个水平,镀液温度选择 70,电流密度80A/m2,试验安排及结果见表 3。表 3正交试验表试验号P盐浓度/(g L-1)氨基磺酸浓度/(g L-1)L浓度/(g L-1)结果镀层外观 结合力 电流效率/%15500灰白好17.41251002灰白好16.24351204灰白好14.80410504发黑好13.865101000白好24.976101202白好36.02715502灰白好20.028151004白好32.079151200白好25.09 由表 3可知,6号和 8号试验结果比较理想,但衡量镀液好坏的关键因素还有均镀能力和阴极极限电流密度两项,故此进行了相关测试。1.2.3镀液性能测试(1)均镀能力 均镀能力采用远近阴极法测定。选用网状镀铂阳极,可以增大表面积,防止阳极极化的影响,两个阳极之间的距离比选 1：3。均镀 能力:T=(K-M近/M远)/(K-1)100%式中T 均镀能力K 远阴极离阳极的距离与近阴极离阳极的距离之比M近 近阴极上电镀后的电极增量M远 远阴极上电镀后的电极增量测试条件:K 值选 3,测试电极镀铂面积均为10 cm2。在电镀温度 70,电流密度 100 A/m2条件下,电镀时间 1 h,测试 5组数据,取平均值。由上式计算可知,6号试验镀液均镀能力为73%,8号试验镀液均镀能力为 86%,8号试验结果优于 6号试验结果。(2)阴极极化曲线测试 极化曲线采用三电极体系测定,以镀液为电解质,温度 70,铂片为辅助电极,饱和甘汞电极为参比电极,辅以饱和氯化钾盐桥,测试结果见图 1。试验表明,6号试验镀液阴极电流密度的极限值为 120 A/m2,8号试验液镀的为 160 A/m2,同样证实 8号试验结果优于 6号试验结果。图 16号和 8号试验阴极极化曲线通过正交试验和镀液性能测试,最后确定 8号试验镀液为最佳配方,即 P 盐 15 g/L,氨基磺酸100 g/L,添加剂 L 4 g/L。添加剂 L 为胺类有机物,它可以提高金属离子在阴极还原时的极化作用,使镀层细致、均匀、平整、光亮。2铂铌电极性能测试(1)结合力测试 将试样沿一直径等于试样厚度的轴反复弯曲 180,结果镀层无起皮、脱落。在试样表面纵横划成 2mm 2mm的小方格,划痕交叉处没有镀层脱落和剥离的现象。在 500 炉温中保温 1 h,立即放入冷水中,镀层无脱落、掉皮现象。可见镀层与基体结合力良好。(2)抗蚀力测试 将镀铂试样在 1：1盐酸中煮沸 5 h,镀层无脱落掉皮,表明镀层耐蚀性优良。(3)镀层厚度测试 用称重法和扫描电镜结合测量可知,镀层最大厚度可达 10 m。(4)极化曲线测试 测量制得的铂铌电极在3%NaC l溶液中的极化曲线见图 2。由图 2可以看出:在较小的电流密度下,随电流密度的增加电位图 2镀铂铌电极在 3%N aCl溶液中的极化曲线铌基镀铂电极的研制38增加较快,但在较高电流密度时电位较为平稳,说明当阳极需要输出较高的电流密度时,阳极本身的电位降不高,电能消耗不大。由此可以看出铂铌电极适合做阳极。3结果和讨论(1)表面预处理 图 3为铌经直接除油和酸洗活化后电镀铂层的表面形貌。从图中可以看出,直接除油后镀铂,镀铂层很不均匀,基体很多地方没有覆盖上铂,经弯折后,铂镀层脱落(图 3a)。而经酸洗活化后铂镀层覆盖了整个基体,铂结晶颗粒为球形,结晶细小,无裂缝(图 3b)。图 3铌基镀铂层的 SEM 形貌500(2)温度 镀液温度低于 60 时,得到的镀层疏松。这是由于镀液温度低时,金属离子的扩散速度变慢,在阴极附近缺乏金属离子,电流效率降低,易发生析氢等负反应,从而使得到的镀层疏松。合适的镀液温度为 60 80。(3)P盐浓度 铂浓度低于 9 g/L 时镀层发暗,甚至出现黑色粉状镀层,提高铂含量可相应提高阴极电流密度,加快沉积速度,但铂含量太高容易使镀层粗糙。铂含量控制在 9 15 g/L之间可以得到光亮的厚铂镀层。(4)氨基磺酸和添加剂含量 氨基磺酸是配位剂,能提高阴极极化,使镀层光亮,其含量应控制在 100 g/L左右,含量过高镀层易产生裂纹并发脆。在其他条件相同下,有无添加剂 L 时得到的镀层的电镜扫描照片见图 4。图 4有无添加剂 L时所得镀层的 SEM 形貌对比 由图 4可以看出,加入添加剂 L后,得到的镀层结晶颗粒更细小,这主要是因为添加剂能有效提高阴极极化强度,从而细化了镀层结晶颗粒。4结论(1)铌基体预处理是保证镀层和基体结合力良好的关键。(2)铌基镀铂最 佳工艺条 件如下:15 g/LPt(NH2)2(NO2)2 2H2O,100 g/L NH2OSO2H,4g/L有机胺类添加剂 L,电流密度 50 150 A/m2,温度 60 80。(3)所得铂镀层细致光亮,厚度可达 10 m。镀层与基体结合力良好,耐蚀性优良。参考文献 1 潘会波.外加电流阴极保护用阳极 J.稀有金属材料与工程,1991,20(4):62.2 张建华.镀铂钛电极的研究 J.广州有色金属学报,2000,10(2):108.3 马时申.热离子发电元件电绝缘涂层和镍镀层制作工艺研究 J.材料保护,2001,34(10):40.4 张玉萍.钛基镀铂工艺研究进展 J.钛工业进展,2002(2):7 8.5 电镀手册 编写组.电镀手册 K.北京:国防工业出版社,1977.674 675.编辑:魏兆军武汉奥邦表面技术有限公司招 聘 启 事武汉奥 邦表面技术有限公 司是通过了ISO9001：2000的高新技术企业,是以科技创新适应市场需求的化学品生产、贸易实体。公司秉承追求卓越品质的宗旨,依靠优良的产品品质,完善的售后服务及雄厚的科技力量,结合现代信息技术及先进管理理念,以团结、诚信、开拓、进取的企业精神,展示于电镀界,并逐步向精细化工、贵金属及特殊化学品研发方向发展。目前我们的产品 LZ-1169环保型三价铬彩色钝化剂、JZ-36三价铬彩色钝化剂、BW-38三价铬蓝白钝化剂、WA水溶漆均已经通过 SGS的质量检测。在前处理、封闭、添加剂、铬产品、精细化工、合金电镀、塑胶电镀等系列产品中有着自己的优势及特点。公司诚邀条件优秀的投资商共同办厂、技术加盟及成果转让。联系电话:[phone] 59503568 59503567传 真:027-83524022E-m ail:铌基镀铂电极的研制te mperature and duration were deter mined to be 80 and 12m in,respectively.The target phosphating fil m prepared underthe opti m ized conditions had unifor m ly distributed -n-A l2O3and increasedwear resistance.Key words:phosphating;-nano-A l2O3;wear resistanceM orphology and Structure of Anodizing Fil m on AluminumPlate Subject to Pore-Enlargement in Phosphoric AcidSONG Chen,LI Shu-ying(School of Che m ical Engineering,Dalian University ofTechnology,Dalian 116012,China)CailiaoBaohu 2006,39(4),21 22(Ch).Anodizing fil m was pre-pared on aluminum plate making use of anodizing at constantvoltage in phosphoric acid.The A l plate coated with the anodi-zing film was then i mmersed in a diluted phosphoric acid(5%)for 6 8 min to allow the processing of pore-enlarge men.t Themorphology and structure of the anodizing film after the process-ing of pore-enlarge mentwere analyzed by means of scanning e-lectronmicroscopy.Itwas found that,after being treated in dilu-ted phosphoric acid,the tiny pores distributed unifor m ly in theanodizing fil m and the enlarged pores had a diameter about 150nm,with the a mount of the pores to be asmuch as 2.5 109/c m2.Moreover,the pore-enlargement in the dilute phosphoricacid caused the original irregular spheric pores in the fil m to betransfor med to regular spheric ones.The size of the pores al mostlinearly increased w ith increasing pore-enlarge ment duration,but at a certain pore-enlarge ment duration the pores lost theirspheric shape and ca me into conjunction w ith each other.Theproper pore-enlargement duration was suggested to be 6 7m in.Key words:alum inum anodizing fil m;phosphoric acid;pore-en-large mentStudy of Low-Temperature Ther mal Shock Resistance ofPlasma-Arc Sprayed Alum ina Ceramic CoatingWANG He-ying,LIDe-yuan,MA Xiao-li(SchoolofM echani-cal Engineering,Shenyang Polytechnic University,Shenyang110023,China)CailiaoBaohu 2006,39(4),23 25(Ch).A-lumina ceramic coating was prepared using plasma arc spraying,and the sa me ceramic coating w ith Fe-Cr-A lmetallic inter medi-ate layer was also prepared using the sa me method.The low-te mperature ther mal shock resistance of the resulting ceramiccoatings at 600 was exa mined.The ther mal shock failuremechanism of the coatings was discussed.It was found that thelow-temperature ther mal shock failure of the titled cera m ic coat-ing was attributed to inter-layer and inner-layer cracks andtheir propagation,which led to peeling off of the cera m ic coat-ings atweaker interfaces.Namely,theA l2O3coatingwasweaklybonded to the substrate,thus the crackswere more liable to gen-erate and propagate at the coating-substrate interface,which fi-nally led to peeling off of the coating and hence ther mal shockfailure.Differing from the A l2O3coating ofmono-phase co mpo-sition,the sa me ceramic coating with a Fe-Cr-A lmetallic inter-mediate layerwas characterized by poor bonding bet ween the ce-ramic particulates,thus in this case the cracks preferentially e-merged and propagatedw ithin the ceramic coating,which finallyled to peeling off of the coating aswel.lIn general,itwas feasi-ble to effectively increase the ther mal shock resistance of theplas ma arc sprayed cera mic coating by introducing ametallic in-ter mediate layer,since themetallic inter mediate layerwas capa-ble of relaxing the ther mal stress in the coating and inhibiting thegeneration and propagation of the cracks.Key words:plas ma arc spraying;cera mic coating;low-tempera-ture ther mal shock resistance;ther mal shock failuremechanismPreparation of Anode for Chrom iu m E lectroplating in Tri-valent Chromiu m Sulfate Bath and Properties of the Elec-troplated Chrom ium CoatingHU Yao-hong,CHEN Li-ge,ZHAO Guo-peng,LI U Jian-ping,HONG Rong(Guangzhou Etsing Plating Research Institu-te,Guangzhou 510170,China)CailiaoBaohu 2006,39(4),26 28(Ch).The electroplating of chromium fro m a trivalentchro m ium bath in engineering has a fatal disadvantage of poorbath stability which is highly dependent on the nature of the an-ode materia.lThus an anode was specifically designed for thepurpose of increasing the trivalent chro m ium bath stability forchro m ium electroplating,by taking into account the methods forpreparing the chromium electroplating anode and the effects ofthe electroplating conditions on the coating perfor mance.Theelectroche m icalbehavior of the anode and the appearance,bond-ing strength,porosity,and corrosion resistance of the chromiumcoating were analyzed by meansof electrochemical test,scanningelectron m icroscopic observation,and Hull cell tes.tThe en-hanced service life of the anode was deter mined using intensifiedlife span tes.t The results indicated that the prepared anode hada long service life and good electroplating perfor mance,while thetarget chromium coating had good co mprehensive properties.Key words:trivalent chro mium salt;chro m ium electroplating;anodeTechnology for Electroplating of Fe-SiC Co mposite Coatingand Study of the Coating PropertiesFU Ping,TI AN Hua,XU Xue,ZHAO Cheng(School of Me-chanical-Electronic Engineering,Q ingdao University of Scienceand Technology,Q ingdao 266042,China)CailiaoBaohu 2006,39(4),29 31(Ch).A specially designed asy mmetric alterna-ting current-direct current power supply was used to prepare e-lectroplated Fe-based composite coating dopedwith SiC particu-lates.Thus the Fe-SiC co mposite coating was obtained usingetching-free Fe electroplating process so as to increase the hard-ness and wear resistance of the Fe coating.The electroplatingprocess was investigated,while the properties of the Fe-SiCcomposite coating were examined aswel.l A s the results,itwasfeasible to prepare Fe-SiC composite coating of desired proper-ties at a fast deposition rate,making use of the electroche m icalcodeposition of the Fe matrix and the doped SiC particulates.The Fe-SiC coating had unifor m thickness,high hardness,goodadherence to the substrate,and good wear resistance,and hencecould be used to effectively extend the service life of so me partsand components forwear prevention.Key words:electroplating;Fe-SiC co mposite coating;free Fe e-lectroplating;asymmetric alternating current-direct current pow-er supplyStudy ofH igh-Voltage Anodizing Technology for M agnesi-um Alloy and Properties of the Anodized Fil mQ I AN Jian-gang,WANG Chun,WANG Xue-li,LI Di,GUOBao-lan(School of M aterials Science,Beijing University ofAeronautics and A stronautics,Beijing 100083,China)CailiaoBaohu 2006,39(4),32 35(Ch).O rthogonal testwas carriedout to establish the opti malhigh-voltage anodizing technology formagnesium alloy,ai m ing at significantly increasing the corrosionresistance of theM g alloy.Themorphology,phase co mposition,valence of ele ments,and corrosion resistance of the anodic fil mwere studied by means of scanning electron microscopy,X-raydiffraction,X-ray photoelectron spectroscopy,total immersiontest,and polarization curve measure men.t A s the results,theopti m ized electrolyte was deter mined to be composed of 10 g/LKOH,5 g/L NaF,5 g/L N a2SiO3,0.5 g/L Na2B4O7,100mL/L glycol,75 mL/L glycerine,50 mL/L componentG,while the optimal anodizing para meterswere suggested as currentdensity 8.9 A/c m2and anodizing duration 30 m in.The anodi-zing fil m obtained at the opti malconditionshad porous structure,and the pores unifor m ly distributed in the fil m had an averagedsize about1 2 m.Moreover,the anodizing fil m was composedofA l2SiO5,M gF2,andMgA l2O4,and showedmuch better cor-rosion resistance than the sa me anodizing fil m prepared usingconventionalCr-containing DOW17 process.Key words:magnesium alloy;anodizing technology;anode fil m;corrosion resistancePreparation of Pt/Nb Electrode fro m N iobiu m-Based Plati-num Electroplating and Perfor mance Study of thePt-Nb E-lectrodeZHANG Yu-ping1,JU He1,WU Hong-rang1,WU Zhi-hong2(1.Taijin Co mpany,NorthwestAcademy of NonferrousM etals,Xian 710016,China;2.School ofM aterials Science and Engineer-ing,Xi an University of Architectural Science and Technology,Xi an 710055,China)Cailiao Baohu 2006,39(4),36 38(Ch).Because of itshighmechanicalstrength,strong corrosionresistance,good conductivity and catalytic activity,P t/Nb elec-trode has been widely used in cathodic protection,industrial e-lectrolysis,preparation of ionwater,and so on.Thus orthogonaltestwas carried out to establish the opti mal technology for thepreparation of P t/Nb electrode from an aqueous electroplatingbath.The perfor mance of the resulting P t/Nb electrode waseval-uated.As the results,the optimized electroplating bath was de-ter m ined to be co mposed of15 g/L Pt(NH2)2(NO2)2 2H2O,100 g/L NH2OSO2H,4 g/L additive(organic a m ine).And theopti mal electroplating parameterswere suggested as current den-sity 50 150A/m2and bath temperature 60 80.The plat-ing bath of the optimized for mulation had good even-plating ca-pacity and could be used to prepare compactand brightPt/Nb e-lectrode of a thickness about 10 m,at a cathode current effi-ciency asmuch as 32%.And the resulting Pt/Nb electrode hadgood perfor mance.Key words:Pt/Nb electrode;niobium-based electroplating;prep-arationEffect of Technological Parameters for Liquid-Phase PulseDischarge of Ti Electrode on the For mation and PropertiesofT iC Coating on Plain Carbon Steel SubstrateJIE X iao-hua,JING A i,LU Guo-hui,LI U Yi-fan,X I E Guang-rong(SchoolofM aterials andEnergy Sources,Guangdong Poly-technic University,Guangzhou 510640,China)Cailiao Baohu2006,39(4),39 41(Ch).W ith a view to the pro m inent eco-no m ic significance in the surface modification of cutting tools u-sing liquid-phase pulse discharge,T i C ceramic coatingwas pre-pared on the surface of45 steel,making use of the low-tempera-ture high-energy plas ma produced between Ti electrode and 45steel i mmersed in liquid kerosene in the presence of continualpulse discharge.The effect of the pulse discharging para meterson the for mation and hardness of the TiC coating was investiga-ted.Results showed that the peak current and pulse on-time hadpri mary effects on the coating for mation,while the pulse off-ti meand depositing ti me had al most no effect on the hardness butthickness of the TiC coating.Itwas feasible to obtain TiC coatingw ith high hardness at a relatively small peak current and shortpulse duration.Key words:Ti electrode;pulse discharging;TiC coating;tech-nological para metersCurrent State and Progress of Research on Copper Inhibi-torsHE Jun,YU Ping,LUO Yun-bai(School ofChe mistry andM o-lecular Science,W uhan University,Wuhan 430072,China)Cail-iaoBaohu 2006,39(4),42 47(Ch).The research progress a-bout copper and copper alloy inhibitors was revie wed.Thus thesynergistic effects a mong copper and its alloy inhibitors and vari-ous other inhibitorswere discussedwith respect to acidicmedium,Cl-containing medium,seawater,and nearly neutral aqueousmedium.The current state and development trend about the re-searchmethod and pretreatment of the inhibitors were briefed a