Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Powder metallurgy

An Investigation on The Effect of Carbon Nanoparticles on The Properties of Carbon Brushes

Ahmed A. Alasady; M. I. Mohammad; Suleyman Basturk Basturk

Engineering and Technology Journal, 2022, Volume 40, Issue 12, Pages 1732-1744
DOI: 10.30684/etj.2022.135387.1270

The demand for carbon brushes with specific properties and improvements in production economics in recent years has led to increased interest in metal-graphite composites. Metal matrix composites are considered excellent materials to obtain properties superior to those of the constituent phases and meet the specific requirements of material application. In the present study, we suggested a new composite material by utilizing nanomaterials to improve the properties of metal-graphite composite material usually used as carbon brushes. This has been achieved by adding different percentages of 0.1-0.5wt % of carbon nanotubes, carbon nanospheres, or both to the metal matrix composite. The samples were prepared by powder metallurgy technique. The XRD results gave a sharp line and indicated a high crystalline structure and little amorphous, which improved the conductivity performance of the composite produced within the structure of this work. The density measurement chart results showed an increase in the amounts of the carbon nano additives leading to a decrease in the density of the sample. The investigation of nano additives on hardness showed that increases in the additive led to reduced hardness. On the other hand, the resistivity values have reduced gradually when there is an increase in the amounts of the carbon nano additives, especially on the CNT, which gives better results than CNS, which we obtained the resistivity value =(0.32 Ωcm), Comparing with commercial-grade containing free of nano additives (1.3Ω cm).

Evaluation of the Microstructure and Mechanical Properties of Al / Fe3O4 Nanocomposites

Suaad M. Jiaad; Khansaa Salman; Ahmed A. Hussein

Engineering and Technology Journal, 2021, Volume 39, Issue 11, Pages 1632-1638
DOI: 10.30684/etj.v39i11.2080

The goal of this research is to study the microstructural analysis and mechanical properties of an aluminum matrix reinforced with different amounts of nano Fe3O4 at (2, 4, 6, 8, and 10wt. %). Al/ Fe3O4 nanocomposites specimens were prepared using the powder metallurgy route. Many examinations, including Field Emission Scanning Electron Microscopy (FESEM) and X-Ray Diffraction (XRD) analysis, were performed on the specimens in this study to determine the microstructure and phases of the nanocomposites. Mechanical tests, such as compressive, microhardness, and wear tests, were also performed to assess the mechanical properties of the nanocomposites. The results of this study show that Fe3O4 nanoparticles have been homogeneously dispersed in the Al matrix by FESEM and XRD examination. While the mechanical tests show improving the compressive strength at 6 wt.% by 5.36%, the highest microhardness was at 10% by 101.6% compared with the pure Al, and improving the wear rate.

Investigation of Corrosion Behavior for Copper-Based Shape Memory Alloys in different Media

E.S. Al-Hassani; A.H. Ali; S.T. Hatem

Engineering and Technology Journal, 2017, Volume 35, Issue 6, Pages 578-586
DOI: 10.30684/etj.35.6A.4

Copper based shape memory materials was interesting group of metal alloys that have a widespread potential in medical and industrial application due to their characteristics ,the possibility of exhibiting shape memory behavior and lower cost. In this research the alloy (Cu-(15-40) wt%Zn-6wt.%Al) has been prepared by powder metallurgy technique Zn element (15, 20, 25, 30, 35, 40 wt%Zn) and fixed percentage of Al content which is 6.wt%Al then aluminum replaced by (Si, Sn, Ni )element at fixed percentage of 6wt.%, in order to study the effect of these elements on SMA. After samples preparation examination were done by using XRD, SEM technique, DSC, Vickers hardness, Archimedes method to measure the porosity percentage and corrosion rate in different solutions (HCl, NaOH and SEAWATER).The XRD and microstructure results show that all samples with and without additives consist of two phases (β-phase) and (α-phase) at room temperature and the addition of alloying elements in these percentages does not have effect on present phases. the hardness increased with zinc content because the formation of intermetallic compound of CuZn that responsible to hardness while The addition of Si ,Sn and Ni leads to lower the hardness than aluminum. The bulk density increased with the alloys without addition alloying elements(Si, Ni and Sn ) while apparent porosity decreased with it the reason for this phenomenon due to the characterization of alloying elements that addition to the alloy. From the results of corrosion test can be show the alloy with 35wt% Zn have the higher corrosion resistance in all media (HCl, NaOH and sea water) and the addition of alloying element lead to improve the corrosion resistance. Finally, it is observed that the Copper base shape memory alloys with these types of additives are suitable for use in different application.

Study the Effect of Addition Different Amount Magnesium Hydroxide and Kaolin on Production of Refractory Magnesite Brick

Firas Farhan Sayyid; Shukry H. Aghdeab; Ali Mundher Mustafa

Engineering and Technology Journal, 2016, Volume 34, Issue 13, Pages 546-553
DOI: 10.30684/etj.34.13A.19

This aim of this research is study the effect of adding different percentages of magnesium hydroxide, kaolin and water on the production of refractory magnesite brick by use transformer process. Firstly transformative process carried out on the magnesium hydroxide and kaolin to obtain fine particle, after that mixture fine particle Burn in electric furnace at temperature (1000 oC ) for (2 hr ). The mixture Formed by using semi dry pressing with (10)% water under pressure (500 Kg/cm2) to obtain forming sample we carried out drying process ,and we can many test from inspection for obtain porosity, density, Water absorption, specific weight and more properties compressive strength . We fined finish refractory brick from light type where the resulted density is equal to ( 1.33 gcm3 ) and suits applications that need to lightness weight with durability.

Effect of (Ta &Nb) on Corrosion Behavior of Nitinol Alloys

Emad S. Al-Hassani

Engineering and Technology Journal, 2016, Volume 34, Issue 9, Pages 1894-1902
DOI: 10.30684/etj.34.9A.15

In this research, a study of the effect of Ta and Nb additions on the corrosion behavior and properties of Ni-Ti shape memory alloys prepared by powder metallurgy is presented. It was found that; the transformation temperatures and phase structures of the samples prepared consist of martensitic and austenitic phases at room temperature. Also, Vickers hardness values increased with increasing of Ta and Nb additions. Porosity percentages decreased with increasing of addition of Ta and Nb. Finally, the corrosion rate decreased with increasing of Ta and Nb additions.

Influence of Acidic and Salt Media on The Corrosion Behavior of Aluminum Matrix Composites Reinforced by Al2O3 Particles

Niven J.Abdal Kadir; Payman S.Ahmed; Saja Amer Abdul Majed

Engineering and Technology Journal, 2014, Volume 32, Issue 10, Pages 2351-2363
DOI: 10.30684/etj.32.10A.3

Corrosion behavior of pure Al and Al/ Al2O3 composite with five weight percent of Al2O3 particles (5,10,15,20 and 25) were investigated in 0.1M H2SO4 and 3.5 % NaCl solutions at room temperature. The composites were prepared by powder metallurgy and their corrosion behavior were evaluated by potentiostatic polarization and scan rate 3mV.sec-1.
It's observed that pure Al/Al2O3 composites exhibited excellent corrosion resistance in NaCl medium than in the H2SO4 media. The pure aluminum exhibited slightly superior corrosion resistance than the composites in NaCl medium but the composites had better corrosion resistance in H2SO4 medium.
Insulator Al2O3 particles are perceived to act as inert material and degrade the integrity of the protective oxide layer on the Al matrix.
Al/Al2O3 composites have lower corrosion rate than pure aluminum in 0.1 M H2SO4, but increasing of wt% of alumina led to increase the corrosion rate. While in 3.5% NaCl solution can be seen that corrosion rate of pure aluminum less than that for composites. Generlly, For certain material, the corrosion rate in salt medium less than in acidic medium.

Effect of Zinc Addition on the Density and Wear Rate of Al-12Si Compacts

Mahde Mter Hanoon

Engineering and Technology Journal, 2012, Volume 30, Issue 18, Pages 382-391
DOI: 10.30684/etj.30.18.14

This research aimed to prepareAl-12Si alloys by powder metallurgy method because of its
commercial and technological importance. Aluminum and Silicon powders were used, then
mixed and blended together and classified into four parts, carbon powder was added to the
three parts (5,10 and 15% wt) and the last remain as it is. These powders were mixed to
ensure a good distribution of Zinc powder, and then they compacted in is ostatic cold pressure
at 10 ton, the compact samples were sintered in furnace under argon gas at 530°C for one
hour, These samples were then prepared (grinded, polished and etched) for them icrostructure
examination, density, porosity, microhardness, X-ray diffraction and wear resistance. The
results showed anincrease in the density and the hardness with addition ratio.

The Effect of Iron Addition on the Dry Sliding Wear and Corrosion Behavior of Cu Al Ni Shape Memory Alloy

Abdul Raheem . K. Abid Ali; Zuheir T. Khulief.Al-Tai

Engineering and Technology Journal, 2010, Volume 28, Issue 24, Pages 6888-6902

In this paper, dry sliding wear and corrosion behavior of Cu + 13wt% Al + 3.8 wt% Ni was prepared by powder metallurgy. Dry sliding wear has been studied based on pin on disk at constant velocity and constant sliding distance .Corrosion behavior in 5 wt% NaOH solution based up on potentiostatic ( Tafel ) has been presented for base shape memory alloy ( Cu + 13% Al + 3.8 % Ni ) in two cases austenitic and martensitic phase state . Further more , the effect of Fe additions as ( 0.4 , 0.8 and 1.2 wt% ) on the sliding wear and corrosion behavior of
base alloy has also been studied .It is clear that Cu Al Ni shape memory alloy in martensitic state has more wear resistance than in austenitic structure . Also , corrosion resistances are better than in martensitic structure because the alloy has corrosion current density as 336.45 μA/cm2 in martansitic where as the corrosion current density is 633.62 μA/cm2 in austenitic structure . Further more , when the
iron content increases , wear and corrosion rate increase too .