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.

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.  

Use of Strain Energy Density W and Qo as Quality Indices for Rating the Quality of Cast Aluminium Alloy354 as a Function of Processing Parameters

2013 ◽  
Vol 704 ◽  
pp. 189-194 ◽  
Author(s):  
Prateek Sibal ◽  
G. Dinesh Babu ◽  
M. Nageswara Rao
Keyword(s):  
Energy Density ◽  
Yield Strength ◽  
Aluminium Alloy ◽  
Aging Temperature ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Artificial Aging ◽  
Heat Treatments ◽  
Cast Aluminium

Cast aluminium alloy 354 has found widespread application in the automotive industry for its excellent mechanical properties and good castability. The stringent emission norms and demands for improved fuel economy have pushed automobile technology to new frontiers. This has led to efforts to reduce weight while maintaining higher vehicle performance. Cast aluminium alloy 354 is a material that performs with reasonable effectiveness in the high stress automobile environment. The present study looks at the use of strain energy density W and the quality index Qo to determine the effect of process parameters like aging temperature and modification on the quality of the alloy 354 and also to monitor the effect of interrupted heat treatments T6I4 and T6I6 on the quality of the material. The strain energy density W calculated for the interrupted heat treatments on alloy 354 show a broad inverse relation with yield strength Rp. An improvement in the yield strength and the strain energy density of the alloy is observed when the alloy is subjected to modification. At artificial aging temperatures lower than the artificial aging temperature adopted in standard aging treatment an improvement in the Qo and W quality of the alloy 354 have been observed.

Effect of Coating Parameters on Coating Rate of Carbon Fibers by Electroless Nickel Plating

2015 ◽  
Vol 830-831 ◽  
pp. 635-638 ◽  
Author(s):  
Madhuri Deshpande ◽  
Rahul Waikar ◽  
Ramesh Gondil ◽  
S.V.S. Narayanmurty
Keyword(s):  
Carbon Fibers ◽  
Surface Condition ◽  
Research Work ◽  
Electroless Nickel ◽  
Sodium Hypophosphite ◽  
Matrix Composites ◽  
Nickel Deposition ◽  
Plating Method ◽  
Acidic Bath

The coating quality of nickel is important factor in improvement of wettability of carbon fibers to be used as reinforcing material in the production of carbon fiber reinforced metal matrix composites. In this research work, Polyacrylonitile (PAN) based carbon fibers have been Ni coated in Sodium hypophosphite reduced acidic bath by electroless plating method. These carbon fibers are coated using 4, 4.5, 5 and 5.5 pH values for 5, 10, 15, 20, 25 and 30minutes. Coating thickness is found to increase with time linearly. Nickel deposition rate per unit time increases with pH, however it reaches a maxima and then declines. The surface condition of fibers reveals that coating becomes more and more rough due to non uniform coating, as coating time and pH goes on increasing.

scholarly journals Numerical Simulation of Effect of Different Initial Morphologies on Melt Hydrodynamics in Laser Polishing of Ti6Al4V

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 581
Author(s):  
Kai Li ◽  
Zhenyu Zhao ◽  
Houming Zhou ◽  
Hao Zhou ◽  
Jie Yin ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Processing Parameters ◽  
Surface Finishing ◽  
Polished Surface ◽  
Laser Polishing ◽  
Starting Position ◽  
Double Spiral ◽  
The Difference ◽  
Thermocapillary Forces ◽  
Surface Morphologies

As a surface finishing technique for rapid remelting and re-solidification, laser polishing can effectively eliminate the asperities so as to approach the feature size. Nevertheless, the polished surface quality is significantly sensitive to the processing parameters, especially with respect to melt hydrodynamics. In this paper, a transient two-dimensional model was developed to demonstrate the molten flow behavior for different surface morphologies of the Ti6Al4V alloy. It is illustrated that the complex evolution of the melt hydrodynamics involving heat conduction, thermal convection, thermal radiation, melting and solidification during laser polishing. Results show that the uniformity of the distribution of surface peaks and valleys can improve the molten flow stability and obtain better smoothing effect. The high cooling rate of the molten pool resulting in a shortening of the molten lifetime, which prevents the peaks from being removed by capillary and thermocapillary forces. It is revealed that the mechanism of secondary roughness formation on polished surface. Moreover, the double spiral nest Marangoni convection extrudes the molten to the outsides. It results in the formation of expansion and depression, corresponding to nearby the starting position and at the edges of the polished surface. It is further found that the difference between the simulation and experimental depression depths is only about 2 μm. Correspondingly, the errors are approximately 8.3%, 14.3% and 13.3%, corresponding to Models 1, 2 and 3, respectively. The aforementioned results illustrated that the predicted surface profiles agree reasonably well with the experimentally measured surface height data.

scholarly journals Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE Materials

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1795
Author(s):  
Norshahira Roslan ◽  
Shayfull Zamree Abd Rahim ◽  
Abdellah El-hadj Abdellah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Katarzyna Błoch ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Thick Plate ◽  
Processing Parameters ◽  
Processing Parameter ◽  
Plastic Injection Moulding ◽  
Optimal Setting ◽  
Quality Of Products ◽  
Validation Tests ◽  
Plastic Injection

Achieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.

Porosity Quatification of Cast Aluminium Alloys on Machined Surfaces Using Metallography and Eddy-Currents

2015 ◽  
Vol 647 ◽  
pp. 188-194
Author(s):  
Břetislav Skrbek
Keyword(s):  
Surface Treatment ◽  
Aluminium Alloys ◽  
Eddy Currents ◽  
Initiation Site ◽  
Cast Aluminium ◽  
Strength And Ductility ◽  
Machined Surfaces

The porosity is unwanted phenomenon mostly that is tried to eliminate. The pores are initiation site of fatigue fractions usually, they worse strength and ductility of materials, quality of machined surfaces and their following surface treatment.

Observation in the Surface Roughness of Silicon Wafer during Semi-Fixed Abrasive Machining with Large Grains

2009 ◽  
Vol 69-70 ◽  
pp. 253-257
Author(s):  
Ping Zhao ◽  
Jia Jie Chen ◽  
Fan Yang ◽  
K.F. Tang ◽  
Ju Long Yuan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Silicon Wafer ◽  
Processing Parameters ◽  
Wafer Surface ◽  
Abrasive Machining ◽  
Fixed Abrasive ◽  
Is Failure ◽  
Better Than

Semi-fixed abrasive is a novel abrasive. It has a ‘trap’ effect on the hard large grains that can prevent defect effectively on the surface of the workpiece which is caused by large grains. In this paper, some relevant experiments towards silicon wafers are carried out under the different processing parameters on the semi-fixed abrasive plates, and 180# SiC is used as large grains. The processed workpieces’ surface roughness Rv are measured. The experimental results show that the surface quality of wafer will be worse because of higher load and faster rotating velocity. And it can make a conclusion that the higher proportion of bond of the plate, the weaker of the ‘trap’ effect it has. Furthermore the wet environment is better than dry for the wafer surface in machining. The practice shows that the ‘trap’ effect is failure when the workpiece is machined by abrasive plate which is 4.5wt% proportion of bond in dry lapping.

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