Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : glass


Studying and Modeling the Effects of Quartz Addition and Heat Treatment on Mechanical Properties of Glass-Ceramic Coating

Ali H. Ataiwi; Ibtihal A. Mahmood; Jabbar H. mohmmed

Engineering and Technology Journal, 2014, Volume 32, Issue 7, Pages 1811-1824

In this work, a new glass-ceramic coating has been developed and applied, as a single coat without prior chemical treatment of the surface, using the dipping technique on metal substrate. the coating are designed for application on varies grades of low alloy steel, the selected substrate was low carbon low alloyed steel with (0.2)%C. Various heat treatments at temperatures ( 500,550, and 600˚C ) at different times (60 & 120)min and with quartz addition in the range (0-15)% were used to obtain a glass-ceramics that have the optimum coating properties. These coating have been characterized by x-ray diffraction analyses and the results showed presence of a number of microcrystalline phases which are formed during the heat treatments. The results showed the suitability of this coating for protection the metal substrate which was used in present work. The results of tests also indicated that the mechanical properties ( hardness, adhesion strength, and thermal stability) of resultant coating were greatly improved by both addition of quartz into enamel frit and heat treatments for all cases, this is attributed to the formation of complex network from crystalline phases(Li2SiO3, Li2TiSiO5, NaAlSi2O6, and SiO2) which are the main phases in the resultant glass-ceramic coating. It has been found that the heat treatment at 600˚C for 120min with 15% quartz addition brought the optimum values for ( hardness, adhesion strength, and thermal stability) of resultant coating which are improved by (70.58%, 33.84%, and 39.68%) respectively. Mathematical modeling is implemented and regression equations are obtained using ( SPSS ) software to predict the experimental data for mechanical properties of resultant coating. Comparing the predicted and measured values gives high prediction accuracy. The accuracy of prediction has been (98%, 98.5%, and 97.4%) for ( hardness, adhesion strength, and thermal stability) respectively.

Modeling of The Corrosion Behavior of Enamel Coatings in Different Aggressive Media

Ibtihal A. Mahmood; Jabbar H. mohmmed; a A. Khalaf; Bayda

Engineering and Technology Journal, 2014, Volume 32, Issue 6, Pages 1530-1543

In this study an attempt has been made to formulate materials for glass ceramic enamel coating that can be applied directly onto cast iron substrate for corrosion control. Different 'proportions(4.95) %wt. to form four batches. The batches were mixed with water to form slips which were used to coat already prepared cast iron surfaces and were allowed to dry in the oven. The coated cast iron plates were fired at temperatures of 850˚C to mature and factually heat treated at 680˚C.
The coatings were observed and also chemical tests were conducted to determine the corrosion properties of the resultant coatings. The chemical tests were evaluated using a suitable standard methods and special attention was paid to the type of aggressive solution, and temperature.
The results show that the coatings matured and adhered very well to the sub strateand showed good corrosion resistance in H2SO4,HCl,C6H8O7, H3PO4, and NaOH solutions. The results indicated that the corrosion rate in both acid and alkali media was increased strongly with the increasing temperature.The coatings prepared with the zircon showed better results in terms of acidcorrosion resistance than those prepared with the other crystalline agents. However, the corrosion rate of the zircon containing coating in sulfuric acid was higher than that in hydrochloric acid. Also, it is found that there is absolutely no weight loss for any of the four types of the coating in neither citric nor phosphoric acids. At the same time, the results for alkali corrosion resistance indicate that the act of the four series is very similar to each other, for the four coatings there is no high corrosion rate until the temperature exceed 100˚C after that the rate increases in a very quick manner. From the results it is found that the enamel with lithium oxide was not affected by the alkali solution at all, this behavior is associated with the presence of crystalline β-Spodumene, and β-Eucryptite, which have an extremely high corrosion resistance especially for alkali medium. Mathematical modeling is implemented and regression equations are obtained by using (SPSS) software to predict the experimental data for acid and alkali corrosion rate. Comparing the predicted and measured values gives high prediction accuracy.

Wear Resistance of a New Glass Ceramic Coating

Jabbar H. mohmmed; Ibtihal A. Mahmood; Ali H. Ataiwi

Engineering and Technology Journal, 2014, Volume 32, Issue 6, Pages 1472-1484

A new wear resistance glass-ceramic coating system iron (low alloyed low carbon steel) based substrate was developed. The effects of heat treatment conditions and mill additions on wear resistance of developed coatings resistance were studied. The coating materials showed excellent properties for protection the iron substrate from wear. Also, in this work mathematical modeling is implemented and regression equations are obtained by using ( SPSS ) software to predict the experimental data for wear rate. Comparing the predicted and measured values gives high prediction accuracy.

Mechanical Properties For Pipes Made From Composite Materials (Glass/ Epoxy And Carbon/ Epoxy) Subjected To Internal Pressure

Zainab K. Hantoosh; Hatam Kareem Kadhom; Aseel Jasim Mohammed

Engineering and Technology Journal, 2012, Volume 30, Issue 6, Pages 117-134

Composite Materials have been used extensively in application such as pipes and pressure vessels. Therefore it is important for further studies on the properties of these materials. This paper presents the results from a series of tensile tests on the mechanical properties of composite materials. Specimens cut from pipes made from composite materials were tested under internal pressure loadings have been tested by using a series of ASTM Standards test methods for mechanical properties. Based on the results obtained, the longitudinal E11,
transverse E22 and shear modulus G12 of 101.2 GPa, 5.718 GPa, 4.346 GPa and 36.6, 5.4 GPa, 4.085 GPa for carbon and glass fiber/ epoxy composites, respectively, while the ultimate longitudinal XL, transverse XT and shear tensile τ0 strengths of 1475.4 MPa, 20 MPa, 36 MPa and 618.9 MPa, 14 MPa, 28 MPa for carbon and glass fiber/epoxy composites, respectively. The results from this series of tests have been presented and compared with results from analytical equations. Good agreement was achieved between the experimental results and
analytical results.

Studying and Modeling The Effects of Quartz Addition and Heat Treatment on Corrosion Properties of Ceramic Coating

Ali H. Ataiwi; Ibtihal A. Mahmood; Jabbar H. mohmmed

Engineering and Technology Journal, 2011, Volume 29, Issue 12, Pages 2564-2579

In this work, a new glass-ceramic coating has been developed and applied, as a single coat without prior chemical treatment of the surface, by using the dipping technique on metal substrate. the coating are designed for application on varies grades of low alloy steel, the selected substrate was low carbon low alloyed steel with (0.2)%C. Various heat treatments at temperatures ( 500,550, and 600˚C ) at different times (60 & 120)min and with quartz addition in the range (0-15)% were used to obtain a glass-ceramics that have the optimum coating properties. These coating have been characterized by x-ray diffraction analyses and the results showed presence of a number of microcrystalline phases which are formed during the heat treatments. The results of corrosion resistance tests indicated that the acid resistance was greatly improved by addition of quartz into enamel frit but at same times decreased the alkali corrosion resistance, while the heat treatments improved both acid and alkali resistance for all cases, this is attributed to the formation of complex network from crystalline phases. The results also indicated that the heat treatment at 600˚C for 120min with 15% quartz addition brought the optimum values for acid resistance property which are improved by 86.66%, while the optimum values for alkali resistance property was brought with free quartz added samples which were treated at 600˚C for 120min. Mathematical modeling is implemented and regression equations are obtained by using ( SPSS ) software to predict the experimental data for acid and alkali corrosion rate. Comparing the predicted and measured values gives high prediction accuracy. The accuracy of prediction has been (82.58%, and 96.7%) for acid and alkali resistance properties respectively.

Study Of The Chemical Durability And Hazardous Ionic Leaching Of(Soda-Lime) Glas

Sanaa A. A. Hafad; Abd al khalaq F. Hammod; Huda A. Hussain

Engineering and Technology Journal, 2009, Volume 27, Issue 15, Pages 2751-2759

Huge amounts of glass materials being applied in medical, pharmaceutical
and chemical aqueous solutions; this requires the study of chemical stability of glass at the exposed surfaces with these solutions where the leaching takes place. The leaching of the glass ions will transport these ions to the solutions stored in the glass containers; leading to changes in the chemical composition in the order of part per million that causes hazardous effect with time. The present work investigates the leaching chemical properties of the soda-lime Iraqi glass containers. The effect of the pH of contact solution and
annealing of glass on leaching rates is studied. Ionic leaching shows lower rate with PH of the solutions at the ‘safe zone’: (6>PH>8.5). Annealing increases the leaching rates and reduces of the chemical durability of glass. Increasing annealing time led to further increase the leaching rate. In addition, the increase in the exposed surface area also increases leaching rates.