scholarly journals Characterization of Electroless Nickel–Boron Deposit from Optimized Stabilizer-Free Bath

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 576
Author(s):  
Muslum Yunacti ◽  
Alexandre Mégret ◽  
Mariana Henriette Staia ◽  
Alex Montagne ◽  
Véronique Vitry

Conventional electroless nickel–boron deposits are produced using solutions that contain lead or thallium, which must be eliminated due to their toxicity. In this research, electroless nickel–boron deposits were produced in a stabilizer-free bath that does not include any toxic heavy metal. During processing, the plating rate increased from 10 to 14.5 µm/h by decreasing the concentration of the reducing agent, leading to increased bath stability. The thickness, composition, roughness, morphology, hardness, wear, and corrosion resistance of the deposits were characterized. The new deposit presents an excellent hardness of 933 ± 56 hv50, 866 ± 30 hk50, and 12 GPa from the instrumented indentation test (IIT), respectively, which are similar to that of hexavalent hard chromium coating. Moreover, by using both potentiodynamic polarization and salt spray tests it was shown that the coating presents higher corrosion resistance as compared to standard nickel-boron coatings. The new deposit exhibits properties close to those of the conventional electroless nickel–boron deposits. Therefore, it could replace them in any industrial applications.

2010 ◽  
Vol 638-642 ◽  
pp. 846-851 ◽  
Author(s):  
Abdoul Fatah Kanta ◽  
Véronique Vitry ◽  
Fabienne Delaunois

Nickel-boron coatings were synthesized on mild steel by the electroless deposition method. Some of the coatings were submitted to a hardening heat treatment at 400°C during 1 hour in an atmosphere containing 95% Ar and 5% H2. Uncoated steel, treated and untreated samples were submitted to the Taber abrasion test to assess their wear resistance. The wear track was then examined by SEM and roughness measurement. The Taber Wear Index of untreated samples was slightly better than that of steel but heat treated samples attained TWI as small as 13. The corrosion resistance of the samples was investigated by the way of polarization and electrochemical impedance spectroscopy (EIS) and the influence of the heat treatment was observed.


Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 70
Author(s):  
Ruifang Zhang ◽  
Kai Lv ◽  
Zhaoxin Du ◽  
Weidong Chen ◽  
Pengfei Ji ◽  
...  

In order to improve the wear and corrosion resistance of micro-arc oxidation (MAO) coating on a Ti-5Al-1V-1Sn-1Zr-0.8Mo alloy, 0–0.20 g/L graphene was added to the electrolyte to prepare micro-arc oxidation coating. The thickness, roughness, micro-morphology, and composition of the MAO coating were characterized, and the wear and corrosion resistance of the coating was tested and analyzed. The results show that with 0.05 g/L of graphene in the electrolyte, the roughness of the coating decreased from 56.76 μm to 31.81 μm. With the increase in the addition of graphene, the microstructure of the coating became more compact, the diameter of micro-holes and micro-cracks decreased, and the corrosion resistance of the coating improved. The wear tests showed that the mass loss of the coating at the early wear stage (0~100 revolutions) was greater than that at the later stage (100~250 revolutions), and the wear resistance of the coating obtained by the addition of 0.10 g/L of graphene was the highest. With 0.10 g/L of graphene, the adhesion force between the coating and the substrate alloy is the largest, reaching 57.1 N, which is 9.98 N higher than that without graphene. After salt spray corrosion for 480 h, the coating with graphene has better corrosion resistance than that of a graphene-free coating.


2013 ◽  
Vol 756-759 ◽  
pp. 60-63
Author(s):  
Xia Chang ◽  
Xiao Bin Zhang

Electroless nickle coating with plain and high binding force was obtained in this experiment .the samples were heat treated and diffused, then microstructure and transformation was investigated by optical microscope and scanning electron microscope. The hardness, binding force, wear and corrosion resistance are tested, the reasonable heat treatment process is gained. Hardness is increased after eletroless nickel plating and heat treatment compared with the matrix. The adhesion of sample heat treated at 400°C is highest, the weight loss and friction coefficient is lowest, the corrosion resistance is best..


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 292
Author(s):  
Irina Smolina ◽  
Karol Kobiela

This paper presents the method of preparation and study results of the Stellite 6 laser surface alloyed (LSA) with rhenium using na LDF diode laser (4000 W). During this process, a rhenium powder was introduced onto the surface of the Co-based alloy. The possibility of improving wear and corrosion resistance properties is interesting and worth investigating. The selected process parameters: the laser power of 900 W, powder feed rate in the range 1.92–3.83 g/min, and necessarily preheating of the substrate up to 200 °C—allowing to obtain the LSA layers on the Stellite 6 substrate. Depending on the process parameters, it is possible to modify the substrate’s surface layer in terms of rhenium concentration and geometrical characteristics of the laser tracks. It was found that undissolved particles of rhenium in laser-alloyed layers have a non-significant effect on their hardness and abrasion resistance. The laser surface-alloyed corrosion potential is better than the corrosion potential of the Stellite 6 substrate, including reducing resistance to pitting corrosion with a high ability to repassivation.


2010 ◽  
Vol 66 ◽  
pp. 86-91 ◽  
Author(s):  
Juliane Vicenzi ◽  
Antonio S. Takimi ◽  
Ricardo B. Fonseca ◽  
Andrei Locatelli ◽  
Célia Fraga Malfatti ◽  
...  

Plasma sprayed alumina coating is applied in many industrial applications in order to promote wear and corrosion resistance. Nonetheless, high porosity remained after deposition is a critical factor because it decreases the wear resistance. Some inorganic sealants can be used to reduce the open pores and superficial micro-cracks effect, improving the wear and corrosion resistance of alumina coatings. In this work, plasma sprayed alumina coating samples were divided into two groups: i) impregnated with inorganic sealant (AlPO4) and heat treated; ii) as deposited. Erosive wear tests were carried out in an erosion rig according to ASTM G76. The samples were subjected to an erodent flux, with impact angles of 30º up to 90º, at a velocity of 50m/s and temperatures of 25°C up to 400°C. The samples were characterized by SEM, Vickers microhardness, potentiodynamic anodic polarization and erosive wear rate. Results showed that erosive wear rate of alumina impregnated coating is lower than without the sealant. The sealed alumina coating presented higher mechanical properties; improved microstructural characteristics and the sealant promoted better lamellae contact, as can be observed by less sharpness in pits formation of microstructure.


RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 52562-52570 ◽  
Author(s):  
Qingyang Li ◽  
Zhongbao Feng ◽  
Jinqiu Zhang ◽  
Peixia Yang ◽  
Fenghuan Li ◽  
...  

A nanocrystalline zinc coating is produced by pulse reverse electrodeposition in a sulfate bath with polyacrylamide as the only additive and the mechanical, wear and corrosion resistance properties are evaluated.


2009 ◽  
Vol 15 (S3) ◽  
pp. 59-60
Author(s):  
N. M. G. Parreira ◽  
T. Polcar ◽  
Y. T. Pei ◽  
D. Galvan ◽  
J. Th. M. De Hosson ◽  
...  

AbstractIn the decorative field, besides the optical characteristics needed for achieving desired colours, the material should have suitable properties able to assure the daily use of the component without significant degradation. Oxides are well known materials with a high wear and corrosion resistance which make them a preferential choice of coatings for environmental protection. However, the intrinsic colours possible to be achieved in a single oxide system are very limited. For example in W-O system, besides the different tonalities of grey, only the dark blue can be obtained for slightly substochiometric WO3 compound. The pallet of colours exhibited by WO3 coatings is due to interferometric effects. Recently, it was shown that playing with the gradient of the chemical composition of W-O layers it was possible to tune the global colour of the coatings, which made this system an attractive candidate for decorative applications.


Alloy Digest ◽  
1961 ◽  
Vol 10 (7) ◽  

Abstract TANTUNG G is a cast nonferrous alloy containing tantalum or columbium carbide and having wear and corrosion resistance. It is used primarily for cutting tools. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: Co-28. Producer or source: Vascoloy, Ramet Division.


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