A Taguchi Design Study for Optimisation of Plasma Sprayed Hydroxyapatite Coatings

2013 ◽  
Vol 773-774 ◽  
pp. 590-601
Author(s):  
Md Fahad Hasan ◽  
James Wang ◽  
Christopher C. Berndt

Plasma sprayed hydroxyapatite coatings were deposited onto mild steel substrates. A Taguchi L9design of experiment protocol was used to optimise the coating process parameters. The effect of three factors: (i) power and secondary gas flow rate (X1), (ii) powder feed rate and carrier gas flow rate (X2), and (iii) stand-off distance (X3) on the coating responses was studied. The responses of the plasma sprayed hydroxyapatite coatings were evaluated in terms of porosity, deposition efficiency, microhardness, crystallinity, and surface roughness. A regression analysis established relationships between process parameters and responses. Higher power, lower powder feed rate and the middle stand-off distance of 11 cm lead to optimum attributes of low porosity, high deposition efficiency, high microhardness, high crystallinity, and high surface roughness.

Author(s):  
Yanmin Zhou ◽  
Haifeng Gu ◽  
Qiunan Sun ◽  
Zhongning Sun ◽  
Jiqiang Su ◽  
...  

Aerosols as the main component of radioactive products in migration performance, which is an important factor that a unclear reactor accident present strong diffusion and affects the distributions of source and dose level in reactor containment, and they are therefore expected to be deposited in liquid phase such as in suspension pool and filtered containment venting device. In this paper, the deposition characteristics of micro-nano aerosols in rising bubble under pool scrubbing condition is studied with experiment, the aerosols size in the research range from 20 nm to 600 nm, and the bubble morphology mainly concern homogeneous bubbly flow. The results show that the deposition efficiency and mechanism of aerosol closely relate to gas flow rate, liquid level, particle size and bubbles size and so on. The aerosol deposition near 85nm is proved most difficult because of the convert of deposition mechanisms. In a high liquid level condition, micro-nano aerosol filtration efficiency is enhanced but gradually gradual. Under different gas flow rate, air bubble residence time and the bubble size distributions affect the filtration efficiency of aerosols.


2007 ◽  
Vol 14 (05) ◽  
pp. 1007-1013 ◽  
Author(s):  
ESAH HAMZAH ◽  
ALI OURDJINI ◽  
MUBARAK ALI ◽  
PARVEZ AKHTER ◽  
MOHD RADZI HJ. MOHD TOFF ◽  
...  

In the present study, the effect of various N 2 gas flow rates on friction coefficient and surface roughness of TiN -coated D2 tool steel was examined by a commercially available cathodic arc physical vapor deposition (CAPVD) technique. A Pin-on-Disc test was carried out to study the Coefficient of friction (COF) versus sliding distance. A surface roughness tester measured the surface roughness parameters. The minimum values for the COF and surface roughness were recorded at a N 2 gas flow rate of 200 sccm. The increase in the COF and surface roughness at a N 2 gas flow rate of 100 sccm was mainly attributed to an increase in both size and number of titanium particles, whereas the increase at 300 sccm was attributed to a larger number of growth defects generated during the coating process. These ideas make it possible to optimize the coating properties as a function of N 2 gas flow rate for specific applications, e.g. cutting tools for automobiles, aircraft, and various mechanical parts.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1443 ◽  
Author(s):  
Maroš Vyskoč ◽  
Miroslav Sahul ◽  
Mária Dománková ◽  
Peter Jurči ◽  
Martin Sahul ◽  
...  

In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al3Mg2 and γ-Al12Mg17, in the inter-dendritic areas of the fusion zone (FZ), Al49Mg32, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al2O3 particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).


2018 ◽  
Vol 9 (1) ◽  
pp. 9-16
Author(s):  
S. A. Rizvi

This research article is focusing on the optimization of different welding process parameters which affect the weldability of stainless steel (AISI) 304H, Taguchi technique was used to optimize the welding parameters and the fracture mode characterization was studied. A number of experiments have been conducted. L9 orthogonal array (OA) (3×3) was applied. Analysis of variance ( ANOVA) and signal to noise ratio (SNR) was applied to determine the effect of different welding parameters such as welding current, wire feed speed and gas flow rate on mechanical, microstructure properties of SS304H. Ultimate tensile strength (UTS), toughness, microhardness (VHN), and mode of fracture was examined to determine weldability of AISI 304H and it was observed from results that welding voltage has major impact whereas gas flow rate has minor impact on ultimate tensile strength of the welded joints. Optimum process parameters were found to be 23 V, 350 IPM travel speed of wire and 15 l/min gas flow rate for tensile strength and mode of fracture was ductile fracture for tensile test specimen.


2013 ◽  
Vol 19 (6) ◽  
pp. 452-462 ◽  
Author(s):  
Mehmet Ermurat ◽  
Mehmet Ali Arslan ◽  
Fehmi Erzincanli ◽  
Ibrahim Uzman

Purpose – This paper aims to investigate the effect of four important process parameters (i.e. laser focal distance, travel speed, feeding gas flow rate and standoff distance) on the size of single clad geometry created by coaxial nozzle-based powder deposition by high power laser. Design/methodology/approach – Design of experiments (DOE) and statistical analysis methods were both used to find optimum parameter combinations to get minimum sized clad, i.e. clad width and clad height. Factorial experiment arrays were used to design parameter combinations for creating experimental runs. Taguchi optimization methodology was used to find out optimum parameter levels to get minimum sized clad geometry. Response surface method was used to investigate the nonlinearity among parameters and variance analysis was used to assess the effectiveness level of each problem parameters. Findings – The overall results show that wisely selected four problem parameters have the most prominent effects on the final clad geometry. Generally, minimum clad size was achieved at higher levels of gas flow rate, travel speed and standoff distance and at minimum spot size level of the laser focal distance. Originality/value – This study presents considerable contributions in assessing the importance level of problems parameters on the optimum single clad geometry created laser-assisted direct metal part fabrication method. This procedure is somewhat complicated in understanding the effects of the selected problem parameters on the outcome. Therefore, DOE methodologies are utilized so that this operation can be better modeled/understood and automated for real life applications. The study also gives future direction for research based on the presented results.


1997 ◽  
Vol 470 ◽  
Author(s):  
G. C. Xing ◽  
D. Lopes ◽  
G. E. Miner

ABSTRACTIn this paper, we report the study of rapid thermal oxidation of silicon in N2O ambient using the Applied Materials RTP Centura rapid thermal processor, and N2O oxide thickness and compositional uniformities with respect to gas flow rate and wafer rotation speed as well as other process parameters. It was found that N2O oxide uniformity is strongly dependent on gas flow rate and wafer rotation speed in addition to process pressure. With optimized setting of the process parameters, excellent oxidation uniformities (one sigma < 1%) were obtained at atmospheric pressure N2O ambient. Nitrogen concentrations of such uniform oxides grown at 1050°C atmospheric pressure N2O oxidation processes were 1.7% for a 40Å oxide and 2.5% for a 60Å oxide, respectively, as characterized by SIMS analysis.


2019 ◽  
Vol 27 (07) ◽  
pp. 1950183
Author(s):  
AREZOO MOSHABAKI ◽  
ERFAN KADIVAR ◽  
ALIREZA FIROOZIFAR

Indium tin oxide (ITO) thin films have been deposited on glass substrate by DC magnetron sputtering in the presence and absence of oxygen gas flux. Subsequently, some of the samples have been annealed in vacuum or air oven at [Formula: see text]C for 20[Formula: see text]min. The optical, surface morphology and electrical characteristics have been examined by spectrophotometry, atomic force microscope, field emission scanning electron microscopy, four-point probe and Hall effect measurements as a function of argon gas flux, film thickness, deposition rate and substrate temperature. Experimental results indicate that the surface roughness increases by decreasing the argon gas flow rate and deposition rate. The result revealed that the lowest surface roughness of 1.07[Formula: see text]nm is achieved at zero oxygen gas flux, argon gas flow 20[Formula: see text]sccm and deposition rate [Formula: see text] Å/s. We have found that the maximum value of merit figure is related to the argon gas flow rate 30[Formula: see text]sccm. In order to obtain a very smooth surface, finally, the ITO thin films have been processed with alumina polishing solution by ultrasonic method. Our experimental results indicate that surface roughness decreases and merit figure increases after polishing process.


Author(s):  
R. Koganti ◽  
C. Karas ◽  
A. Joaquin ◽  
D. Henderson ◽  
M. Zaluzec ◽  
...  

The development of lightweight vehicles, in particular aluminum intensive vehicles, require significant manufacturing process development for joining and assembling aluminum structures. Currently, 5xxx and 6xxx aluminum alloys are being used in various structural applications in a number of lightweight vehicles worldwide. Various joining methods, such as MIG, Laser and adhesive bonding have been investigated as technology enables for high volume joining of 5xxx, and 6xxx series alloys. In this study, metal inert gas (MIG) welding is used to join 5754 non-heat-treatable alloy sheet products. The objective of this study is to develop optimum weld process parameters for non-heat-treatable 5754 aluminum alloys. The MIG welding equipment used in this study is an OTC/Daihen CPD-350 welding systems and DR-4000 pulse power supply. The factors selected to understand the influence of weld process parameters on the mechanical properties and metallurgy (weld penetration) include power input (torch speed, voltage, current, wire feed), pulse frequency, and gas flow rate. Test coupons used in this study were based on a single lap configuration. A full factorial design of experiment (DOE) was conducted to understand the main and interaction effects on joint failure and weld penetration. The joint strengths and weld penetrations are measured for various operating ranges of weld factors. Post weld analysis indicates, power input and gas flow rate are the two signficant factors (statistically) based on lap shear load to failure and weld penentration data. There were no 2-way or 3-way interaction effects observed in ths weld study. Based on the joint strength and weld penetration, optimum weld process factors were determined.


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