Electroless nickel coatings present complementary properties: coatings formed using hypophosphite present usually better corrosion resistance while those made with borohydride present better mechanical and wear properties. Duplex coatings, combining both kinds of deposits, are designed to combine features of both nickel–phosphorus (ENP) and nickel–boron (ENB) coatings. In this study, monolayer and bilayer coatings were synthesised on mild steel substrates, in various combinations of ENP and ENB, with a total thickness of 20 µm and heat treated (400°C – 1 h) under non-reactive atmosphere (95% Ar–5% H2) to enhance their mechanical properties. The morphology, roughness, hardness, abrasive wear resistance and scratch behaviour of the coatings were investigated. Samples with ENP as the top layer showed a higher roughness than samples with ENB as the external layer. However, samples with ENB as the top layer provided better wear resistance, even if they presented a lower combined hardness. ENB monolayer showed the best resistance to scratch testing.
SudagarJ, LianJ, ShaW.Electroless nickel, alloy, composite and nano coatings – a critical review. J Alloys Compd.2013;571:183–204. doi: 10.1016/j.jallcom.2013.03.107
5.
ShakoorRA, KahramanR, GaoW, Synthesis, characterization and applications of electroless Ni-B coatings – a review. Int J Electrochem Sci.2016;11:2486–2512.
6.
VitryV, DelaunoisF.Electroless nickel-phosphorous vs electroless nickel-boron: comparison of hardness, abrasion resistance, scratch test response and corrosion behavior. In: AliofkhazraeiM, editor. Comprehensive guide for nanocoatings technology. Volume 1, Deposition and mechanism. New York
: Nova Science Publishers; 2015. p. 145–173.
7.
OhnoI.Electrochemistry of electroless plating. Mater Sci Eng. 1991;146:33–49. doi: 10.1016/0921-5093(91)90266-P
8.
CharbonnierM, RomandM, GoepfertY.Ni direct electroless metallization of polymers by a new palladium-free process. Surf Coatings Technol.2006;200:5028–5036. doi: 10.1016/j.surfcoat.2005.05.006
9.
WangZC, JiaF, YuL, Direct electroless nickel-boron plating on AZ91D magnesium alloy. Surf Coatings Technol.2012;206:3676–3685. doi: 10.1016/j.surfcoat.2012.03.020
10.
WangM-QQ, YanJ, DuS-GG, A novel process of electroless nickel plating on PVC with semi-IPN hydrogel pretreatment. J Alloys Compd.2013;557:270–273. doi: 10.1016/j.jallcom.2013.01.016
11.
CorreaE, ZuletaAAA, SepúlvedaM, Nickel–boron plating on magnesium and AZ91D alloy by a chromium-free electroless process. Surf Coatings Technol.2012;206:3088–3093. doi: 10.1016/j.surfcoat.2011.12.023
12.
RiedelW.Electroless nickel plating. Metals Park, OH
: W ASM International ;1991.
13.
NarayananTSNS, KrishnaveniK, SeshadriSK.Electroless {NiP/NiB} duplex coatings: preparation and evaluation of microhardness, wear and corrosion resistance. Mater Chem Phys.2003;82:771–779. doi: 10.1016/S0254-0584(03)00390-0
14.
DelaunoisF, VitryV.Electroless nickel–boron coatings: process, composition, microstructure, and properties. In: TottenGE,, ColasR, editors. Encyclopedia of iron, steel, and their alloys. New York
: CRC Press, Taylor and Francis Group; 2015. p. 1161–1178.
15.
RiddleYW, BailerTO.Friction and wear reduction via an {Ni-B} electroless bath coating for metal alloys. JOM. 2005;57:40–45. doi: 10.1007/s11837-005-0080-7
16.
VitryV, DelaunoisF.Formation of borohydride-reduced nickel–boron coatings on various steel substrates. Appl Surf Sci.2015;359:692–703. doi: 10.1016/j.apsusc.2015.10.205
17.
AnikM, KörpeE, ŞenE.Effect of coating bath composition on the properties of electroless nickel–boron films. Surf Coatings Technol.2008;202:1718–1727. doi: 10.1016/j.surfcoat.2007.07.031
18.
ZhangWXX, JiangZHH, LiGYY, Electroless Ni-P/Ni-B duplex coatings for improving the hardness and the corrosion resistance of AZ91D magnesium alloy. Appl Surf Sci.2008;254:4949–4955. doi: 10.1016/j.apsusc.2008.01.144
19.
VitryV, SensA, KantaAF, Wear and corrosion resistance of heat treated and as-plated Duplex NiP/NiB coatings on 2024 aluminum alloys. Surf Coatings Technol.2012;206:3421–3427. doi: 10.1016/j.surfcoat.2012.01.049
20.
VitryV, BoninL.Formation and characterization of multilayers borohydride and hypophosphite reduced electroless nickel deposits. Electrochim Acta.2017;243:7–17. doi: 10.1016/j.electacta.2017.04.152
21.
BoninL, VitryV.Mechanical and wear characterization of electroless nickel mono and bilayers and high boron-mid phosphorous electroless nickel duplex coatings. Surf Coatings Technol.2016;307:957–962. doi: 10.1016/j.surfcoat.2016.10.021
22.
VitryV, BoninL, MaletL.Chemical, morphological and structural characterisation of electroless duplex NiP/NiB coatings on steel. Surf Eng. 2017;34(6):475–484. doi: 10.1080/02670844.2017.1320032
23.
DelaunoisF, LienardP.Heat treatments for electroless nickel-boron plating on aluminium alloys. Surf Coatings Technol.2002;160:139–148. doi: 10.1016/S0257-8972(02)00415-2
24.
ChenCK, FengHM, LinHC, The effect of heat treatment on the microstructure of electroless Ni–P coatings containing SiC particles. Thin Solid Films.2002;416:31–37. doi: 10.1016/S0040-6090(02)00628-4
25.
DervosCT, NovakovicJ, VassiliouP.Vacuum heat treatment of electroless Ni–B coatings. Mater Lett.2004;58:619–623. doi: 10.1016/S0167-577X(03)00581-0
26.
VenkatakrishnanPG, NazirudeenSSM, NarayananTSNS.Structural characterization and mechanical properties of as-plated and heat treated electroless Ni-B-P alloy coatings. International Journal of Engineering and Technology. 2014;6:1059–1064.
27.
PalS, VermaN, JayaramV, Characterization of phase transformation behaviour and microstructural development of electroless Ni-B coating. Mater Sci Eng A.2011;528:8269–8276. doi: 10.1016/j.msea.2011.07.060
28.
VitryV, KantaAF, DilleJ, Structural state of electroless nickel-boron deposits (5wt.% B): characterization by XRD and TEM. Surf Coatings Technol.2012;206:3444–3449. doi: 10.1016/j.surfcoat.2012.02.003
29.
KeongK, ShaW, MalinovS.Hardness evolution of electroless nickel–phosphorus deposits with thermal processing. Surf Coatings Technol.2003;168:263–274. doi: 10.1016/S0257-8972(03)00209-3
30.
SheinIR, MedvedevaNI, IvanovskiiAL.Electronic and structural properties of cementite-type M3X (M=Fe, Co, Ni; X=C or B) by first principles calculations. Phys B Condens Matter.2006;371:126–132. doi: 10.1016/j.physb.2005.10.093
31.
VitryV, KantaAF, DelaunoisF.Mechanical and wear characterization of electroless nickel-boron coatings. Surf Coatings Technol.2011;206:1879–1885. doi: 10.1016/j.surfcoat.2011.08.008
32.
FinchCB, CavinOB, BecherPF.Crystal growth and properties of trinickel boride, NI3B. Journal of Crystal Growth. 1984;67:556–558. doi: 10.1016/0022-0248(84)90050-2
33.
CurtisD.Case hardening nickel alloys. Mater Des.1993;14:349–350. doi: 10.1016/0261-3069(93)90111-8
34.
NavaD, DávalosCE, Martínez-HernándezA, Effects of heat treatment on the tribological and corrosion properties of electrodeposited Ni-P alloys. Int J Electrochem Sci. 2013;8.
VitryV, KantaAF, DelaunoisF.Evolution of reactive concentration during borohydride-reduced electroless nickel-boron plating and design of a replenishment procedure. Ind Eng Chem Res.2012;51:9227–9234. doi: 10.1021/ie202687y
38.
VitryV, BoninL.Increase of boron content in electroless nickel-boron coating by modification of plating conditions. Surf Coatings Technol.2017;311:164–171. doi: 10.1016/j.surfcoat.2017.01.009
39.
HamidZA, HassanHB, AttyiaAM.Influence of deposition temperature and heat treatment on the performance of electroless Ni–B films. Surf Coatings Technol.2010;205:2348–2354. doi: 10.1016/j.surfcoat.2010.09.025
40.
RajagopalI.Electroless and electrodeposition of nickel boron composites. Bull Mater Sci.1983;5:323–331. doi: 10.1007/BF02744046
41.
SahooP, DasSK.Tribology of electroless nickel coatings – a review. Mater Des.2011;32:1760–1775. doi: 10.1016/j.matdes.2010.11.013
42.
HiggsCE.The effect of heat treatment on the structure and hardness of an electrolessly deposited nickel-phosphorus alloy. Electrodepos Surf Treat.1974;2:315–326. doi: 10.1016/0300-9416(74)90007-8
43.
KeongKG, ShaW, MalinovS.Hardness evolution of electroless nickel–phosphorus deposits with thermal processing. Surf Coatings Technol.2004;168:263–274. doi: 10.1016/S0257-8972(03)00209-3
44.
ApachiteiI, TichelaarFD, DuszczykJ, The effect of heat treatment on the structure and abrasive wear resistance of autocatalytic {NiP} and {NiP--SiC} coatings. Surf Coatings Technol.2002;149:263–278. doi: 10.1016/S0257-8972(01)01492-X
45.
RabizadehT, AllahkaramSR, ZarebidakiA.An investigation on effects of heat treatment on corrosion properties of Ni–P electroless nano-coatings. Mater Des2010;31:3174–3179. doi: 10.1016/j.matdes.2010.02.027
46.
MafiIR, DehghanianC.Studying the effects of the addition of TiN nanoparticles to Ni–P electroless coatings. Appl Surf Sci.2011;258:1876–1880. doi: 10.1016/j.apsusc.2011.10.095
VitryV.2010. Electroless nickel-boron deposits: Synthesis, formation and characterization; Effect of heat treatments; Analytical modeling of the structural state [dissertation]. University of Mons, Belgium.
49.
PalaniappaM, SeshadriSK.Friction and wear behavior of electroless Ni-P and Ni-W-P alloy coatings. Wear. 2008;265:735–740. doi: 10.1016/j.wear.2008.01.002
50.
VitryV, SensA, DelaunoisF.Comparison of various electroless Nickel coatings on steel: structure, hardness and abrasion resistance. Mater Sci Forum. 2014;783–786:1405–1413. doi: 10.4028/www.scientific.net/MSF.783-786.1405
51.
DelaunoisF.. 2002. les dépôts chimiques de nickel-bore sur alliages d'aluminium [dissertation]. University of Mons, Belgium.
52.
BalarajuJN, PriyadarshiA, KumarV, Hardness and wear behaviour of electroless Ni–B coatings. Mater Sci Technol.2016;32:1654–1665. doi: 10.1080/02670836.2015.1137683
53.
PeelersP, HoornGVD, DaenenT, Properties of electroless and electroplated Ni-P and its application in microgalvanics. Electrochim Acta.2001;47:161–169. doi: 10.1016/S0013-4686(01)00546-1
