scholarly journals Effects of Hard Surface Grinding and Activation on Electroless-Nickel Plating on Cast Aluminium Alloy Substrates

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Olawale Olarewaju Ajibola ◽  
Daniel T. Oloruntoba ◽  
Benjamin O. Adewuyi
Keyword(s):  
Aluminium Alloy ◽  
Electroless Nickel ◽  
Sodium Hypophosphite ◽  
Palladium Chloride ◽  
Alloy Sample ◽  
Sand Cast ◽  
Hard Surface ◽  
Cast Aluminium ◽  
Surface Polishing ◽  
Cylinder Piston

This work examined effects of hard surface polishing grits and activation on electroless-nickel (EN) plating on cast aluminium alloy substrates in sodium hypophosphite baths. As-received aluminium alloy sample sourced from automobile hydraulic brake master cylinder piston was melted in electric furnace and sand cast into rod. The cast samples were polished using different grits (60 μm–1200 μm) before plating. The effects on adhesion, appearance, and quantity of EN deposits on substrates were studied. Observation shows that the quantity of EN deposit is partly dependent on the alloy type and roughness of the surface of the substrates, whereas the adhesion and brightness are not solely controlled by the degree of surface polishing. The best yield in terms of adhesion and appearance was obtained from the activation in zincate and palladium chloride solutions. Higher plating rates (g/mm2/min) of 3.01E-05, 2.41E-05, and 2.90E-05 were obtained from chromate, zincate, and chloride than 8.49E-06, 8.86E-06, and 1.69E-05 as obtained from HCl etched, NaOH, and H2O activated surfaces, respectively.

scholarly journals Comparative effects of corrosion on electroless -nickel plated A6061 alloys in DOT3 brake fluid

2018 ◽  
Vol 7 (2) ◽  
pp. 927
Author(s):  
Olawale O. Ajibola ◽  
Peter A.Olubambi
Keyword(s):  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Electroless Nickel ◽  
Master Cylinder ◽  
Brake Fluid ◽  
Hardness Tester ◽  
Corrosion Rates ◽  
Hydraulic Brake ◽  
Cast Aluminium ◽  
Cylinder Piston

Aluminium alloys used in automobile brake master cylinder pistons wear by corrosion due to contamination and chemical reaction of the contacting brake fluid. The study investigates the corrosion of electroless-nickel (EN) deposition enhanced cast aluminium alloy master cylinder piston surfaces immersed in hydraulic brake oil. Cast specimens were produced from the as-received wrought A6061 alloy scrap by sand casting. EN plated as-received and cast aluminium alloys specimens were immersed fully in brake oil for 1680 hours and corrosion rates were determined every 24 hours. Test samples were characterised using the hardness tester, atomic absorption spectrometer, metallurgical photo-microscope, x-ray diffractometer; and SEM with EDX attachment. Both surfaces corroded in the order of electroless-nickel plated cast aluminium alloy (ENCA) < electroless-nickel plated as-received aluminium alloy (ENAA) at 0.0235 and 0.0251 rates (mg/mm2/y) results which showed improvement in the corrosion resistance with significant influence of electroless-nickel coating in reducing corrosion rates of aluminium alloy in brake oil.  

scholarly journals Effect of Processing Parameters on the Protective Quality of Electroless Nickel-Phosphorus on Cast Aluminium Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Olawale Olarewaju Ajibola ◽  
Daniel Toyin Oloruntoba ◽  
Benjamin O. Adewuyi
Keyword(s):  
Aluminium Alloy ◽  
Surface Condition ◽  
Electroless Nickel ◽  
Processing Parameters ◽  
Solution Ph ◽  
Cast Aluminium ◽  
Time Variations ◽  
Surface Morphologies ◽  
Best Fit

The effects of temperature, pH, and time variations on the protective amount and quality of electroless nickel (EN) deposition on cast aluminium alloy (CAA) substrates were studied. The temperature, pH, and plating time were varied while the surface condition of the substrate was kept constant in acid or alkaline bath. Within solution pH of 5.0–5.5 range, the best quality is obtained in acid solution pH of 5.2. At lower pH (5.0–5.1), good adhesion characterised the EN deposition. Within the range of plating solution pH of 7.0 to 11.5, the highest quantity and quality of EN deposition are obtained on CAA substrate in solution pH of 10.5. It is characterised with few pores and discontinuous metallic EN film. The quantity of EN deposition is time dependent, whereas the adhesion and brightness are not time controlled. The best fit models were developed from the trends of result data obtained from the experiments. The surface morphologies and the chemical composition of the coating were studied using the Jeol JSM-7600F field emission scanning electron microscope.

ELECTROLESS NICKEL

Alloy Digest ◽  
1986 ◽  
Vol 35 (4) ◽  
Keyword(s):  
Nickel Coating ◽  
Chemical Reduction ◽  
Electroless Nickel ◽  
Heat Treating ◽  
Corrosion And Wear ◽  
Sodium Hypophosphite ◽  
Work Piece ◽  
Nickel Ions ◽  
Continuous Contact ◽  
Chemical Corporation

Abstract ELECTROLESS NICKEL is a nickel coating deposited by chemical reduction of nickel ions. The most widely used reducing agent is sodium hypophosphite. The thickness of the deposited coating is uniform over all areas of the work-piece that are in continuous contact with fresh plating solution. The process is applicable to a wide variety of metal and nonmetal substrates. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion and wear resistance as well as heat treating and joining. Filing Code: Ni-332. Producer or source: Occidental Chemical Corporation.

Preparation of cast aluminium alloy-mica particle composites

1980 ◽  
Vol 15 (5) ◽  
pp. 1241-1251 ◽  
Author(s):  
Deonath ◽  
R. T. Bhat ◽  
P. K. Rohatgi
Keyword(s):  
Aluminium Alloy ◽  
Cast Aluminium

Study of Crack Propagation Behavior on Low Cycle Fatigue in Squeeze Cast Aluminium Alloy

2000 ◽  
Vol 183-187 ◽  
pp. 1017-1022
Author(s):  
Kazuhiro Morino ◽  
Fumihito Nishimura ◽  
Kunimasa Takahashi ◽  
Yun Hae Kim ◽  
Hironobu Nisitani
Keyword(s):  
Crack Propagation ◽  
Aluminium Alloy ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Squeeze Cast ◽  
Cast Aluminium ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

A Comparative Study on Infrared Thermography during Ultrasonic Fatigue Testing of Cast Steel 42CrMo4 and Cast Aluminium Alloy AlSi7Mg

2013 ◽  
Vol 592-593 ◽  
pp. 501-504 ◽  
Author(s):  
Dominik Krewerth ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
Aluminium Alloy ◽  
Infrared Thermography ◽  
Fatigue Testing ◽  
Cast Steel ◽  
Material Testing ◽  
Initiation Point ◽  
Testing Method ◽  
Cast Aluminium ◽  
Ultrasonic Fatigue ◽  
Non Destructive

The present paper illustrates a comparison of infrared thermography during ultrasonic fatigue testing of cast steel 42CrMo4 and cast aluminium alloy AlSi7Mg. Against the background of different material properties (e.g. mechanical properties as well as thermal properties) the benefit of this non-destructive material testing method in terms of determining the crack initiation point and time during fatigue testing as well as crack propagation is evaluated and discussed. Moreover, correlations between fractography and infrared thermography are performed for both materials.

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