化学镀镍磷合金英文文献

An investigation on effects of heat treatment on corrosion properties of Ni–P electroless nano-coatings

Taher Rabizadeh,Saeed Reza Allahkaram *,Arman Zarebidaki

School of Metallurgy and Materials Engineering,University College of Engineering,University of Tehran,P.O.Box 11155-4563,Tehran,Iran

a r t i c l e i n f o Article history:

Received 19January 2010Accepted 15February 2010

Available online 17February 2010Keywords:C.Coating

C.Heat treatment E.Corrosion

a b s t r a c t

Electroless Ni–P coatings are recognized for their excellent properties.In the present investigation elec-troless Ni–P nano-crystalline coatings were prepared.X-ray diffraction technique (XRD),scanning elec-tron microscopy (SEM),potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)were utilized to study prior and post-deposition vacuum heat treatment effects on corrosion resis-tance together with the physical properties of the applied coatings.

X-ray diffraction (XRD)results indicated that the As-plated had nano-crystalline structure.Heat treat-ment of the coatings produced a mixture of polycrystalline phases.The highest micro-hardness was achieved for the samples annealed at 600°C for 15min due to the formation of an inter-diffusional layer at the substrate/coating interface.

Lower corrosion current density values were obtained for the coatings heat treated at 400°C for 1h.EIS results showed that proper heat treatments also enhanced the corrosion resistance,which was attributed to the coatings’structure improvement.

ó2010Elsevier Ltd.All rights reserved.

1.Introduction

Since the invention of electroless plating technology in 1946by A.Brenner and G.Riddell,electroless nickel (EN)coatings have been actively and widely studied [1,2].

Nano-crystalline Ni–P alloys show a high degree of hardness,wear resistance,low friction coef?cient,non-magnetic behavior and high electro-catalytic activity.Today such Ni–P alloys are widely used in the electronic industry as under-layer in thin ?lm memory disks and in a broad range of other evolving technological applications.It is generally accepted that only nano-crystalline al-loys –irrespective of the way of production –show high corrosion resistance.Indeed,electrodeposited Ni–P alloys with crystalline structure (6–11at.%P)showed anodic dissolution in 0.1M NaCl.On nano-crystalline samples (17–28at.%P)a current arrest was found instead [3–5].

To explain high corrosion resistance of Ni–P electroless coatings different models have been proposed,but the issue is still under discussion:a protective nickel phosphate ?lm,the barrier action of hypophosphites (called ‘‘chemical passivity”),the presence of phosphides,a stable P-rich amorphous phase or the phosphorus enrichment of the interface alloy-solution were proposed.Note that such phosphorus enrichment at the interface was reported

by some of the authors to explain the outstanding corrosion resis-tance of Fe70Cr10P13C7amorphous alloys [5].

Electroless Ni–P alloys are thermodynamically unstable and eventually form stable structures of face-centered cubic (fcc)Ni crystal and body-centered tetragonal (bct)nickel phosphide (Ni 3P)compounds.Different results have been reported regarding the microstructures in the As-deposited condition and the stable phases after heat treatments.For low P and medium P alloys,nickel crystal precipitated ?rstly and Ni 3P followed;however,Ni 3P and (or)Ni x P y compounds such as Ni 2P,Ni 5P 2,Ni 12P 5,and Ni 7P 3occur ?rstly in high P alloys [6–8].

In general,the hardness of the electroless Ni–P coatings can be improved by appropriate heat treatment,which can be attributed to ?ne Ni crystallites and hard inter-metallic Ni 3P particles precip-itated during crystallization of the amorphous phase [8–10].

The main reasons for heat treatment are:(1)to eliminate any hydrogen embrittlement in the basic metal,(2)to increase deposit hardness or abrasion resistance,(3)to increase deposit adhesion in the case of certain substrate and (4)to increase temporary corro-sion resistance or tarnish resistance [11].

The crystallization and phase transformation behavior of elec-troless-plated Ni–P deposits during thermal processing has also been the subject of various investigations;it has been shown that different alloy compositions and heat treatment conditions could affect both the corrosion resistance and crystallization behavior of the deposit [8].

0261-3069/$-see front matter ó2010Elsevier Ltd.All rights reserved.doi:10.1016/j.matdes.2010.02.027

*Corresponding author.Tel./fax:+982161114108.E-mail address:akaram@ut.ac.ir (S.R.Allahkaram).

Materials and Design 31(2010)

3174–3179

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Materials and Design

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des

The aim of this work is to study the post-deposition heat treat-ment effects and corrosion behavior of electroless deposited nano-crystalline Ni–P alloys.The temperature dependence of the coating structures and compositions were also evaluated and discussed.

2.Experimental procedures

2.1.Deposition of electroless Ni–P coating

The deposition was performed on API-5L X65steel substrates (30?25?15mm)with a composition of(Fe:base,Mn:1.42,Si: 0.199,Cu:0.144,Mo:0.132,C:0.061,Nb:0.0538,Al:0.0417,Sn: 0.0167,Ti:0.0142,Cr:0.0126,P:0.01).The substrate surface was carefully polished with SiC emery papers(from grades#100to #400).All the specimens were subjected to the following pre-treat-ment and plating procedure:

1.Ultrasonic cleaning in acetone.

2.Rinsing by immersion in distilled water at room tempera-

ture(RT)for2min.

3.Cleaning in20vol.%H2SO4at RT for30s.

4.Rinsing by immersion in distilled water at RT for2min.

5.Cleaning in5vol.%H2SO4at RT for30s.

6.Rinsing by immersion in distilled water at RT for2min.

7.Electrocleaning in solution containing75g/l sodium

hydroxide(NaOH),25g/l sodium sulfate(Na2SO4),75g/l

sodium carbonate(Na2CO3),at room temperature for

20min.The current density applied was10mA/cm2in

accordance to ASTM G1.

8.Rinsing by immersion in distilled water at RT for30s.

For deposition,the substrates were dipped into commercial electroless nickel bath(SLOTONIP70A from Schlotter)with sodium hypophosphite as reducing agent for2h.This bath provided Ni–P deposits with a medium phosphorous content,9–10%P.Tempera-ture changed within88–93°C and pH changed within 4.5–4.7 range,during coating process.

2.2.Heat treatment and hardness measurement of Ni–P coatings

In order to study the?lm properties,coated samples were ther-mally treated in a vacuum environment.The coatings were isother-mally heat treated at different conditions that gave maximum hardness,i.e.200°C(for2h),400°C(for1h),600°C(for 15min).During heating process,the total pressure in the chamber was maintained below1mbar.Then the samples were allowed to cool down,for at least15min in the high vacuum environment prior to their exposure to the atmosphere.

The hardness of coatings was measured using an(AMSLER D-6700)Vickers diamond indenter at a load of100g for a loading time of20s.The average of?ve repeated measurements is reported.

2.3.Morphology and microstructure of Ni–P coatings

The morphology and microstructure of the coatings were stud-ied using scanning electron microscopy SEM,(CAMSCAN MV2300). X-ray diffraction(XRD)patterns were obtained using Philip’s Xpert pro type X-ray diffractometer with a cobalt target and an incident beam mono-chromator(k=1.7889?).

2.4.Electrochemical measurements

Corrosion behavior of As-plated and heat treated electroless Ni–P coatings was studied by using potentiodynamic polarization test and electrochemical impedance spectroscopy(EIS)in3.5wt.%NaCl solution.The tests were carried out in a standard three-electrode cell using an EG&G potentiostat/galvanostat,model273A.Plati-num plate and Ag/AgCl electrode were used as counter and refer-ence electrodes,respectively.Potentiodynamic polarization test was carried out by sweeping the potential at a scan rate of 1mV sà1within the range of±400mV vs.open circuit potential (OCP).The EIS tests were undertaken using a Solartron Model SI 1255HF Frequency Response Analyzer(FRA)coupled to a Princeton Applied Research(PAR)Model273A potentiostat/galva-nostat.The EIS measurements were obtained at(OCP)in a frequency range of0.01Hz–100kHz with an applied AC signal of 5mV(rms)using EIS software model398.The equivalent cir-cuit simulation program(ZView2)was used for data analysis,syn-thesis of the equivalent circuit and?tting of the experimental data.

3.Results and discussion

3.1.Micrograph and structure

Fig.1shows the SEM images of the surface morphologies of Ni–P coatings before and after vacuum heat treatment at different con-ditions.As it can be seen heat treatment at different temperatures has not had any signi?cant effect on morphology of the coatings.

Fig.2shows the cross section image with line scan analysis of Ni–P coating heat treated at600°C(for15min)which shows the formation of an inter-diffusional layer and its elemental distribu-tion that affects the coating properties.

Atoms under low temperature heat treatment(below400°C) can have short-range movement which is called structural relaxa-tion such as annihilation of point defects and dislocations within grains and grain boundary zones rather than long range diffusion [4].The higher the temperature is,the greater the atomic vibration energy is.As the temperature of the metal increases,more vacan-cies are present and more thermal energy is available,and so the diffusion rate is higher at higher temperatures[11].

Hence,production of an inter-diffusional layer,formed as a re-sult of inter-diffusion of nickel and phosphorous from the coating to the substrate and iron in the reverse direction from the sub-strate will develop upon heating at600°C.

3.2.XRD analyses of Ni–P coatings

Fig.3shows XRD patterns of As-deposited and heat treated Ni–P coatings.The results show that both the phase composition and phase transformation behavior of the electroless Ni–P deposits de-pended on the heating temperatures.

There was no signi?cant change in XRD patterns observed for the samples treated at200°C and only a single broad amorphous pro?le was found,indicating that no phase transition took place at this tem-perature.When the heat treatment temperature was increased to 400°C,new XRD peaks corresponding to crystalline fcc Ni and Ni x P y appeared,indicating that the second phase precipitation was initi-ated.At this temperature,the diffraction peaks corresponding to the metastable Ni8P3,fcc nickel and stable Ni3P phases in the XRD pro?le can be seen.At600°C the fcc Ni and Ni3P peaks intensities in-creased with the heat treatment temperature.Therefore,the Ni8P3 metastable phase was decomposed completely at this temperature. Similar behavior has also been observed by Huangs et al.[12].

Regarding the intensities of fcc nickel diffraction peaks,they are increased and the full width at half maximum(FWHM)became narrower with increasing the heat treatment temperature to 600°C.In the case of As-plated condition,using FWHM of 6.4676°and Scherrer equation,the grain size was estimated as1.5nm.

T.Rabizadeh et al./Materials and Design31(2010)3174–31793175

With regards to the FWHM of 5.496°at 200°C,0.9774at 400°C and 0.4027°at 600°C for fcc nickel peaks,the grain sizes were esti-mated as 1.7,10.9and 26.6nm,respectively.Therefore it can be deduced that the grain size of the crystalline nickel increases sub-stantially with increasing temperature,i.e.reaching to the maxi-mum size of 26.6nm at 600°C.This effect has also been con?rmed by other investigators exposing Ni–P coatings to various heat treatment conditions [13,14].3.3.Hardness of electroless Ni–P deposits

Hardness was measured for the deposits at various annealing temperature.The variations in micro-hardness with annealing temperatures are shown in Fig.4.Heat treatment in the region of 200°C does not bring about any signi?cant changes in the deposit properties.It can be observed that there is a marginal decrease of hardness from 612.3Hv to 525.3Hv between room temperature and 200°C.This small decrease in the hardness may be due to hydrogen embrittlement and internal stress relieving [11].

Signi?cant increase of hardness from 625.3Hv to 875.7Hv is observed after haet treatment at 400°C.The dispersion hardening effect may also be a reason for increase in hardness due to heat treatment above 200°C.Between 200°C and 400°C,the precipita-tion of Ni x P y compounds occurs.The precipitation of nickel phos-phides (Ni 3P)can be seen in the heat treated condition (Fig.3).The mechanism involved in the steep increase in hardness may be due to the precipitation hardening of a typical supersaturated solid solution,for which the atoms of the solute diffuse to a speci?c crystallography plane with an atomic arrangement that resembles the array of atoms on a plane in the structure of the precipitate.As the atoms attempt to precipitate,they are forced to conform to the structure of the solvent.This forced coherency between atoms of the solvent and atoms attempting to form the precipitate causes severe localized stresses in the matrix.These stresses are

responsi-

Fig.1.SEM morphology images of As-plated and heat treated EN coating:(a)As-plated,(b)HT-200°C (2h),(c)HT-400°C (1h)and (d)HT-600°C (15min)in a vacuum environment.

3176T.Rabizadeh et al./Materials and Design 31(2010)3174–3179

ble for the increase in hardness.When suf?cient numbers of atoms are collected,the structure of the precipitate is formed and the

localized stresses are relieved,since the forced coherency between the matrix and the precipitated atoms reaches a maximum level [11].

Intermediate processes during the formation of inter-metallic compounds can result in precipitation or age hardening.Particles of a precipitate form when suf?cient atoms diffuse to a

particular

Fig.2.Line scan analysis and elemental distribution around inter-diffusional layer of Ni–P coating heat treated at 600°C (for 15

min).

Fig.3.XRD spectra of electroless Ni–P coatings measured before and after heat treated at different

conditions.

Fig.4.Microhardness of As-plated and heat treated Ni–P electroless coatings.

T.Rabizadeh et al./Materials and Design 31(2010)3174–31793177

location to form a volume of material that has the correct stoichi-ometric composition and that is large enough so that a boundary can form around it.Before the volume of material reaches this crit-ical size,its atomic arrangement and that of the surrounding ma-trix must remain continuous.This coherency between regions having different inter-atomic spacing results in severe straining,which hardens the alloy [11].

Around 600°C,the hardness reaches to a maximum value of 938Hv.As it can be seen in XRD patterns of the coatings,the inten-sity peaks of the precipitation phases have increased with raising heat treatment temperature above 400°C.This implies that more precipitation phases have been formed.In addition,the formation of an inter-diffusion layer can enhance the hardness of coating.This layer develops upon heating above 600°C and thickens with increasing annealing time.3.4.Electrochemical results

3.4.1.Potentiodynamic polarization studies

Fig.5shows the potentiodynamic polarization curves obtained for As-plated and heat treated electroless Ni–P coating in 3.5wt.%NaCl solution.Table 1lists the open circuit and corrosion potential E corr together with the corrosion current density i corr of these coatings.

By combining Fig.5and Table 1,the corrosion potential of Ni–P deposits is positively shifted from à0.376to à0.25V with increas-ing the annealing temperature to 600°C.Moreover,the corrosion current density (i corr )of heat treated sample at 400°C is 1?10à5(A/cm 2)which has the lowest corrosion current density among all the heat treated specimens.

It is evident from literature reports on Ni–P coatings that pref-erential dissolution of nickel occurs at open circuit potential,lead-ing to the enrichment of phosphorus on the surface layer [15–20].The enriched phosphorus surface reacts with water to form a layer of adsorbed hypophosphite anions (H 2PO à2).This layer in turn will block the supply of water to the electrode surface,thereby pre-venting the hydration of nickel [15],which is considered to be the ?rst step to form either soluble Ni 2+species or a passive nickel ?lm [19,20].

3.4.2.Electrochemical impedance spectroscopy studies

Fig.6shows the Nyquist plots obtained for As-plated and heat treated coatings in 3.5%sodium chloride solution at their respec-tive open circuit potentials.All the curves appear to be similar (Ny-quist plots),consisting of a single semi-circle in the high frequency regions signifying the charge controlled reaction.However,it should be noted that though these curves appear to be similar with

respect to their shape,they differ considerably in their size.This indicates that the same fundamental processes must be occurring on all these coatings but over a different effective area in each case [19,20].

To account for corrosion behavior of As-plated and heat treated electroless Ni–P coatings in 3.5%sodium chloride solution at their respective open circuit potentials,an equivalent electrical circuit model given in Fig.7has been utilized to simulate the metal/solu-tion interface and to analyze the Nyquist plot [19,20].

The charge transfer resistance R ct and double layer capacitance C dl obtained for As-plated and heat treated electroless Ni–P coat-ings are compiled in Table 2.The open circuit potential (OCP),a reliable parameter that indicates the tendency of these systems to corrode,is also included in the same table,along with R ct and C dl values for effective comparison.The occurrence of a single semi-circle in the Nyquist plots indicates that the corrosion pro-cess of these coatings involves a single time constant [19].

A similar conclusion of the existence of a single time constant has been reported by Zeller [21],Van DerKouwe [22]and Lo et al.[23]for the corrosion of electroless Ni–P coatings in sodium chloride and sodium hydroxide solutions at the respective open circuit potentials [19].

The high values of charge transfer resistance (R ct ),in the range 18,172–52,903X cm 2,obtained for the coatings of present

study

Fig.5.Potentiodynamic polarization curves of As-plated and heat treated electro-less Ni–P coatings in 3.5%sodium chloride solution.Table 1

Corrosion characteristics of As-plated and heat treated electroless Ni–P coatings in 3.5%sodium chloride solution by potentiodynamic polarization technique.Type of coating E corr (V vs.Ag/AgCl)i corr (A/cm 2)As-plated

à0.37610?10à5HT-200°C,2h à0.355 6.3?10à5HT-400°C,1h à0.321?10à5HT-600°C,15min

à0.25

2.5?10à5

Fig.7.Equivalent electrical circuit model used to analyze the EIS data of the As-plated and heat treated electroless Ni–P coatings.

3178T.Rabizadeh et al./Materials and Design 31(2010)3174–3179

imply a better corrosion protective ability of heat treated coatings than the As-plated electroless Ni–P coating.

The capacitance value obtained for As-plated and heat treated electroless Ni–P coatings are in the order of23–38l F/cm2.The C dl value is related to the porosity of the coating.The low C dl values con?rm that the heat treated electroless Ni–P coatings of present study are relatively less porous in nature.

By comparing electrochemical parameters and from EIS data of As-plated and heat treated Ni–P electroless coatings in3.5%so-dium chloride solution and from XRD patterns,it can be see that because As-plated coating is nano-crystalline in nature,it has more grain boundaries,hence it is less protective.By increasing heat treatment temperatures from200°C to600°C coatings become denser and less porous that decreasing C dl value proves this.At 200°C,there is grain growth that reduces grain boundaries and its corrosion properties are better than As-plated sample.At 600°C and400°C it is expected that the alloys consist of two con-stituents:crystals of the nickel-rich phase and the Ni x P y phases. Therefore,it can be observed that alloys are not continuous,be-cause they have surface inhomogeneities(grain boundaries and second phase),which are active sites for corrosion attack.Thus, the mixtures of two phases with two different compositions,prob-ably produces active–passive corrosion cells within the alloy,caus-ing it to suffer sever chemical attack.

At400°C formation of second phases of Ni x P y have to decrease the corrosion resistance of coating but grain growth at this temper-ature triumph the formation of second phases and the corrosion resistance increases.After heat treatment at600°C because of increasing second phases’quantity,the corrosion resistance de-creases compare to400°C.

4.Conclusions

Nano-crystalline Ni–P electroless coatings was deposited on X65steel samples.The heat treatment effects on coating properties were systematically studied.The results show that:

(1)As-deposited Ni–P coating has a homogeneous nano-crystal-

line structure.

(2)By applying heat treatment,second phase precipitation

occurred around400°C.

(3)The highest hardness was obtained after heat treatment

temperature at600°C for15min because of formation of an inter-diffusional layer and Ni3P phase and sealing porosities.

(4)Proper heat treatment can signi?cantly improve the corro-

sion resistance of these coatings.

References

[1]Hu YJ,Xiong L,Meng JL.Electron microscopic study on interfacial

characterization of electroless Ni–W–P plating on aluminium alloy.Appl Surf Sci2007;253:5029–34.

[2]Dong D,Chen XH,Xiao WT,Yang GB,Zhang PY.Preparation and properties of

electroless Ni–P–SiO2composite coatings.Appl Surf Sci2009;255:7051–5. [3]Bozzoni B,Lenardi C,Serra M,Faniglulio M.Electrochemical and X-ray

photoelectron spectroscopy investigation into anodic behaviour of electroless Ni–9á5wt.%P in acidic chloride environment.Brit Corros J2002;37:173–81. [4]Ashassi-Sorkhabi H,Rafezadeh SH.Effect of coating time and heat treatment

on structures and corrosion characteristics of electroless Ni–P alloy deposits.

Surf Coat Technol2004;176:318–26.

[5]Crobu M,Scorciapino A,Elsener B,Rossi A.The corrosion resistance of

electroless deposited nano-crystalline Ni–P alloys.Electrochim Acta 2008;53:3364–70.

[6]Jiaqiang G,Yating W,Lei L,Bin S,Wenbin H.Crystallization temperature of

amorphous electroless nickel–phosphorus alloys.Mater Lett2005;59:1665–9.

[7]Yu HS,Luo SF,Wang YR.A comparative study on the crystallization behavior of

electroless Ni–P and Ni–Cu–P deposits.Surf Coat Technol2001;148:143–8. [8]Tachev D,Georgieva J,Armyanov S.Magnetothermal study of nanocrystalline

particle formation in amorphous electroless Ni–P and Ni–Me–P alloys.

Electrochim Acta2001;47:359–69.

[9]Wang LP,Gao Y,Xu T,Xue QJ.Corrosion resistance and lubricated sliding wear

behaviour of novel Ni–P graded alloys as an alternative to hard Cr deposits.

Appl Surf Sci2006;252:7361–72.

[10]Yan M,Ying HG,Ma TY.Improved microhardness and wear resistance of the

as-deposited electroless Ni–P coating.Surf Coat Technol2008;202:5909–13.

[11]Mallory GO,Hajdu JB.Electroless plating:fundamentals and applications.

Reprint ed.Florida:AESF;1990.

[12]Huang YS,Zeng XT,Hu XF,Liu FM.Heat treatment effects on EN–PTFE–SiC

composite coatings.Surf Coat Technol2005;198:173–7.

[13]Elsener B,Crobu M,Scorciapino MA,Rossi A.Electroless deposited Ni–P alloys:

corrosion resistance mechanism.J Appl Electrochem2008;38:1053–60. [14]Re′ve′sz A,Lendvai J,Loranth J,Padar J,Bakonyi IJ.Nanocrystallization studies of

an electroless plated Ni–P amorphous alloy.J Electrochem Soc 2001;148:715–20.

[15]Diegle RB,Sorensen NR,Nelson GC.Dissolution of glassy Ni–P alloys in H2SO4

and HCl electrolytes.J Electrochem Soc1986;133:1769–76.

[16]Diegle RB,Sorensen NR,Clayton CR,Helfand MA,Yu YC.An XPS investigation

into the passivity of an amorphous Ni–20P alloy.J Electrochem Soc 1988;135:1085–92.

[17]Carbajal JL,White RE.Electrochemical production and corrosion testing of

amorphous Ni–P.J Electrochem Soc1988;135:2952–7.

[18]Habazaki H,Deng SQ,Kashima A,Asami K,Hashimoto K,Inoue A,et al.The

anodic behavior of amorphous Ni–19P alloys in different amorphous states.

Corros Sci1989;29:1319–28.

[19]Balaraju JN,Sankara Narayanan TSN,Seshadri SK.Evaluation of corrosion

resistance of electroless Ni–P and Ni–P composite coatings by electrochemical impedance spectroscopy.J Solid State Electrochem2001;5:334–8.

[20]Balaraju JN,Ezhil Selvi V,William Grips VK,Rajam KS.Electrochemical studies

on electroless ternary and quaternary Ni–P based alloys.Electrochim Acta 2006;52:1064–74.

[21]Zeller III RL.Electrochemical corrosion testing of high phosphorus electroless

nickel in5%NaCl.Corrosion1991;47:692–702.

[22]Van Der Kouwe ET.EIS as a means of evaluating electroless nickel deposits.

Electrochim Acta1993;38:2093–7.

[23]Lo PH,Tsai WT,Lee JT,Hung MP.The electrochemical behavior of electroless

plated Ni–P alloys in concentrated NaOH solution.J Electrochem Soc 1995;142:91–6.

Table2

Electrochemical parameters from EIS data of As-plated and heat treated Ni–P

electroless coatings in3.5%sodium chloride solution.

Type of coating OCP(mV vs.Ag/AgCl)R ct(X cm2)C dl(l F/cm2)

As-platedà34313,93438.334

HT-200°C,2hà32418,17232.952

HT-400°C,1hà24152,90328.154

HT-600°C,15minà25627,35223.823

T.Rabizadeh et al./Materials and Design31(2010)3174–31793179

钢铁的化学镀镍磷

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化学镀镍磷合金英文文献

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化学镀镍磷合金加工

化学镀镍磷合金加工 作者：上传日期： 业务范围：专业从事化学镀镍磷合金加工业务 加工技术：金属表面化学镀NI--P工艺，全面取代电镀处理本公司加工工艺可在钢、铸铁、铝合金、铜合金等材料表面形成光亮如镜的镍 磷合金 镀层，硬度可高达HV1000，相当HRC69，具有很高的耐磨性和耐腐蚀性，镀层结合 力好、厚 度均匀。镀速快，可达20μm/小时。 一、技术特性： 1、耐腐蚀性强：该工艺处理后的金属表面为非晶态镀层，抗腐蚀性特别优良，经硫 酸、盐 酸、烧碱、盐水同比试验，其腐蚀速率低于1cr18Ni9Ti不锈钢。 2、耐磨性好：由于催化处理后的表面为非晶态，即处于基本平面状态，有自润滑性。 因 此，磨擦系数小，非粘着性好，耐磨性能高，在润滑情况下，可替代硬铬使用。 3、光泽度高：催化后的镀件表面光泽度为LZ或▽8-10可与不锈钢制品媲美，呈白 亮不锈钢 颜色。工件镀膜后，表面光洁度不受影响，无需再加工和抛光 4、表面硬度高：经本技术处理后，金属表面硬度可提高一倍以上，在钢铁及铜表面 可达 Hv 570。镀层经热处理后硬度达Hv 1000，工模具镀膜后一般寿命提高3倍以上。

5、结合强度大：本技术处理后的合金层与金属基件结合强度增大，一般在 350-400Mpa条件 下不起皮、不脱落、无气泡，与铝的结合强度可达102-241Mpa。 6、仿型性好：在尖角或边缘突出部分，没有过份明显的增厚，即有很好的仿型性， 镀后不 需磨削加工，沉积层的厚度和成份均匀。 7、工艺技术高适应性强：在盲孔、深孔、管件、拐角、缝隙的内表面可得到均匀镀 层，所 以无论您的产品结构有多么复杂，本技术处理起来均能得心应手，绝无漏镀之处。 8、低电阻，可焊性好。 9、耐高温：该催化合金层熔点为850-890度 二．适镀基材：铸铁、钢铁、铜及铜合金、铝及铝合金，模具钢、不锈钢。 三．化学镀镍磷合金层的性能（国家钢铁产品质量监督检验中心检测） 按GB10125-1997标准规定进行测试，时间为96小时，Nacl浓度50g/l,ph值： 6.5- 7.2，温度：35，按GB6464-86规定评定防护等级，可达9级。 磷含量（质量百分数）：6%-12% 电阻率：60-75μΩ.cm 密度：7.9g/cm3 熔点：860-880℃ 硬度：镀态：Hv500-550(45-48RCH) 热处理后：Hv1000 结合力：400MPa，远高于电镀 内应力：钢上内应力低于7Mpa 本单位生产销售化学镀镍浓缩液、添加剂，光亮剂、浸锌剂、钝化封闭剂等，设计 制作化学镀镍生产线，承揽化学镀镍加工 我厂为客户服务的方式有以下几种： 一、镀覆加工各种工件。

化学镀镍磷问题

化学镀镍磷问题 100 [ 标签：化学镀镍磷 ] 匿名 2010-10-29 21:59 在碳钢上镀镍磷，原理，用料，步骤，我要交个实验设计的，求高手解答，绝对高分。 满意答案好评率：100% 本发明涉及一种镁合金化学镀镍磷的 方法，属化学镀膜工艺技术领域。本 发明的特征在于具有以下工艺过程和 步骤：①配制化学镀液；其组成及重 量配方为：主盐碱式碳酸镍１０～３ ０ｇ／Ｌ；还原剂次亚磷酸钠２０～ ４０ｇ／Ｌ；络合剂乳酸１５～２５ ｇ／Ｌ，丁二酸４～８ｇ／Ｌ，乙酸 钠１０～２０ｇ／Ｌ，柠檬酸３～１ ５ｇ／Ｌ，选上述络合剂中的一种或 多种；稳定剂硫脲０．５～３．０ｍ ｇ／Ｌ，碘酸钠５～１５ｍｇ／Ｌ， 选上述稳定剂中的一种或二种；防腐 剂氟化氢铵１５～３０ｇ／Ｌ；余量 为水。②将镁合金脱脂、酸洗，清洁 表面。③浸锌处理、退锌、二次浸锌。 ④化学镀镍；温度８０～９０℃，ｐ Ｈ６～７，施镀时间４５～６０分钟。 ⑤水洗，并在２００℃下热处理２小 时；最后获得厚度为１５～２０微米 的镍磷合金镀层。 镁合金化学镀镍磷的方法 一种镁合金化学镀镍磷的方法，其特征在于具有以下的工艺过程和步 骤：ａ．首先制备好镀镍磷化学镀液，该镀液的化学组成及 其重量配方如下：主盐碱式碳酸镍：１０～３０ｇ／Ｌ； 还原剂次亚磷酸钠：２０～４０ｇ／Ｌ；络合剂柠檬酸或柠 檬酸三钠：３～１５ｇ／Ｌ，乳酸：１５～２５ｇ／Ｌ，丁二酸：４～ ８ｇ／Ｌ，乙酸钠：１０～２０ｇ／Ｌ，选上述络合剂中的一种或多 种；稳定剂硫脲：０．５～３ｍｇ／Ｌ，碘酸钠：５～１５ ｍｇ／Ｌ，选上述稳定剂中的一种或二种；防腐剂氟化氢铵： １５～３０ｇ／Ｌ；余量为水；ｂ．将镁合金事先 进行脱除油脂处理，然后进行酸洗；酸洗是将表面清洁的镁合金部件 放入氢氟酸和磷酸的混合酸液中；该混合酸液是浓度为４０％的氢氟 酸与浓度为６８％的磷酸以１∶１体积比配制而成；酸洗２０～５０

化学镀镍磷合金技术 NI-p 简介

化学镀镍磷合金技术 NI-p 简介 高性能的镍磷合金化学镀工艺是近年来迅速发展起来的一种新型表面保护和表面强化技术手段，具有广泛的应用前景。目前化学镀镍磷合金已广泛地应用在石油化工、石油炼制、电子能源、汽车、化工等行业。石油炼制和石油化工是其最大的市场，并且随着人们对其镀层特性的认识，它的应用也越来越广泛，主要用在石油炼制、石油化工的冷换设备上，并且得到了许多用户的认可。经实际应用，能显著提高设备的耐磨、耐蚀性能，延长其寿命3倍以上，性能优于目前使用的有机涂料，而且适用于碳钢、铸铁、有色金属等不同基材。 1、化学镀镍磷合金的原理 其主要反应为次亚磷酸钠还原镍离子为金属镍，即在水溶液中镍离子和次亚磷酸根离子碰撞时，由于镍触媒作用析出原子态氢，而原子态氢又被催化金属吸附并使之活化，把水溶液中的镍离子还原为金属镍形成镀层，另外次亚磷酸根离子由于在催化表面析出原子态氢的作用，被还原成活性磷，与镍结合形成Ni－P 合金镀层。 2、镀层的特性及技术指标 (1)镀层均匀性好 非晶态Ni－P合金镀层是通过化学沉积的方法获得，凡是镀液能浸到的部位，任何形态复杂的零件，都能得到均匀的镀层。不需外加电流，是非晶态均一单相组织，不存在晶界、位错，也无化学成份偏析,且避免了电镀形成的边角效应等缺陷。另外，镀层十分致密还具有较高的光洁度。 (2)镀层附着力好 镀层在钢铁基体上产生压应力（4MPa），而镀层与钢的热膨胀系数相当，所以具有优良的附着力，一般为300－400MPa。 (3)镀层硬度高，抗磨性能优良 镀层具有高硬度，低韧性和较低热导率、电导率，它的抗拉强度超过700MPa，与很多合金钢相似，镀层硬度和延伸率都超过了电镀铬，弯曲无裂纹，但不适合反复弯折和拉抻等剧烈变形的部件，经热处理硬度可达HV1100，但在320℃时开始发生晶型转变，耐磨性能增强，耐蚀性能减弱。 (4)优良的抗腐蚀性能 由于镀层为非晶态，不存在晶界、位错等晶体缺陷，是单一均匀组织，不易形成电偶腐蚀，决定其有较高的耐蚀性，Ni－P镀层均匀性好，拉应力小，致密性好，为防止介质的腐蚀提供了理想的阻挡层。在碱、盐、高温油测、有机介质和溶剂、酸性气体中有抗蚀能力，经实际应用证明，特别对石油炼制、石油化工中的Cl-应力腐蚀，高低温H2S和环烷酸的腐蚀具有超凡的抗蚀能力。