scholarly journals INHIBITOR EFFICACY AND COMPOSITION OF OAK BAR EXTRACT

Author(s):  
Olha HULAI ◽  
◽  
Vasylyna SHEMET ◽  
Vasyl ZHILKO ◽  
Olena KLYMOVYCH ◽  
...  

Regional and international researchers have proven that natural products, plants and their extracts can be used to reduce the corrosion rate. Such studies are relevant because natural inhibitors are obtained from renewable sources, therefore they are environmentally friendly. Ukrainian scientists have investigated the inhibition effect of oak bark extracts, but no such studies have been performed on cast iron. What is more, it has not been established which substances cause this effect. The purpose of the study is to determine the corrosion resistance of 08kp steel and gray cast iron SCh-15 (common structural materials of food industry equipment) in acidic and neutral environments in presence of oak bark extracts; to define the qualitative composition of the extract. Structure of cast iron and steel samples was studied on a metallographic microscope MMP-14C. The corrosion rate of metals was evaluated by weight. To determine the corrosion potential, we used a setting of a cathode voltmeter, electrodes (test and saturated chloride-silver), an intermediate vessel with a saturated KCl solution and electrolytic keys filled with the test electrolyte and saturated KCl solution (for the comparison electrode). The extract was analyzed on a Shimadzu GCMS-QP2020 gas chromatograph with mass-selective detection. Using weight method, the inhibition effect of oak shavings alcohol extract was proved in acidic and neutral corrosive environments. Under the influence of oak bark extract (5%), the stationary potential of steel 08kp has shifted: in 3% NaCl solution (oxygen depolarization) – towards more negative values; in 5% HCl solution (hydrogen depolarization) – to less negative values. Gas chromatography with mass-selective detection (GC/MS) revealed that the active substance in the extract is a mixture of natural tannins – polyphenolic compounds with a molecular weight of 500 to 3000. The inhibition effect of natural tannins is probably enhanced by siloxane compounds.

2017 ◽  
Vol 18 (2) ◽  
pp. 524-538
Author(s):  
Marc Philibert ◽  
Sofia Mendaza ◽  
Flavia Zraick ◽  
Benjamin Rabaud

Abstract The internal corrosion of cast iron and steel pipes is one of the main issues that drinking water distribution operators are facing. This study evaluated the relevance of 10 known corrosion indices according to their estimate of corrosion rate and iron particle release for 20 different water qualities. Pilot-scale contact trials were run over 45 days using cast iron and steel coupons. Corrosion rate was measured by coupon weight-loss and by an online linear polarization rate probe. Particle release was monitored by an online turbidimeter. The results showed that none of the indices properly predicted the level of risk associated with each water and that corrosion and particle release were not correlated. Two novel indices were developed to predict the corrosion and particle release risks independently of each other. The corrosion index showed a strong linear correlation with the corrosion rate of cast iron and slightly less reliable results for steel. The Particle Emission Index presented good correlation with turbidity in waters following contact with cast iron. These two indices thus showed interesting potential as tools to limit internal corrosion risks for metal pipes in water distribution networks.


Alloy Digest ◽  
1964 ◽  
Vol 13 (1) ◽  

Abstract MEEHANITE-GD is a high strength iron casting having high damping capacity, self-lubricating properties, and good machinability. It combines the good properties of both cast iron and steel. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on casting, heat treating, machining, and joining. Filing Code: CI-32. Producer or source: Meehanite Metal Corporation.


Alloy Digest ◽  
1954 ◽  
Vol 3 (1) ◽  

Abstract MEEHANITE GA is a high strength iron casting having high damping capacity, self-lubricating properties, and good machinability. It combines the good properties of both cast iron and steel. Applications include machine tools, gears, shafts, and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on heat treating and machining. Filing Code: CI-5. Producer or source: Meehanite Metal Corporation.


Author(s):  
P.A. Tsirkov ◽  
V.G. Vyalkov ◽  
S.N. Glazunov ◽  
L.D. Varlamova

The study is devoted to method for restoration of worn cylindrical and fl at surfaces of products made of cast iron and steel using ER70S-6 welding wire at moderate welding currents by electric arc surfacing.


Author(s):  
D. T. Oloruntoba ◽  
O. S. Adesina ◽  
O. F. Abraham ◽  
K. J. Akinluwade

This research focused on the corrosion behavior of gray cast iron and aluminum in alkaline medium (0.5 M NaOH) with and without inhibitor (water hyacinth Eichhornia crassipes extract) of varying concentrations of 5%, 10%, 15%, 20% and 25%. The corrosion rates of the metal samples were investigated using the weight loss and electrochemical methods alongside the formulation of a dispersant using readily available chemicals to develop a colloidal solution of the extract produced by hot water digestion of the water hyacinth plant leaves. The metallography tests of control samples as well as the most and least corroded samples were carried out using Optical Microscope (OM). The results revealed that the aluminum resulted in minimum corrosion rate of 0.000483 mg/mm2/yr with inhibitor efficiency of 98.93% obtained for sample A5 (25% extract from water hyacinth) while for the gray cast iron, a minimum corrosion rate of -4.4E-05 mg/mm2/yr with inhibitor efficiency of 566.6% obtained for sample C3 (15% extract from water hyacinth). The electrochemical result of aluminum showed increase in corrosion potential from -1.494 VAg/AgCl to -1.482 V Ag/AgCl and that of gray cast iron from -0.5436 VAg/AgCl to -0.2839 VAg/AgCl upon increase in inhibitor concentration. Therefore, the use of water hyacinth (Eichhornia crassipes)extract reduced the corrosion or dissolution rate of gray cast iron and aluminum in (NaOH) sodium hydroxide medium.


Author(s):  
V.G. VYALKOV ◽  
S.N. GLAZUNOV ◽  
P.A. TSIRKOV

In experiment, worked out the parameters of deposition and the composition of the ferromagnetic charge, which ensure a defect-free weld layer (no pores, inclusions, hot and cold cracks) with a surface hardness of 52- 56 HRC without additional technological measures (heating products) and subsequent heat treatment.


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