scholarly journals Laser Texturing as Substrate Preparation Technique for Improved Corrosion Performance on WC-Co HVOF Coatings on AZ91D

2018 ◽  
Vol 7 (2) ◽  
pp. 80-86
Author(s):  
Sachpreet Singh Aulakh ◽  
Gagandeep Kausha ◽  
Neeraj Bala
Keyword(s):  
Chemical Properties ◽  
Electrochemical Corrosion ◽  
Surface Characteristics ◽  
Vital Role ◽  
Preparation Technique ◽  
Corrosion Performance ◽  
Substrate Preparation ◽  
Laser Texturing ◽  
Electrochemical Testing ◽  
Good Surface

Substrate preparation plays a vital role in the performance of thermal spray coatings. Adherence of the coating to the substrate depends on surface characteristics like; mechanical interlocking, physio-chemical properties of surface and metallurgical bonding. The surface characteristics depend to great extent on the method used for substrate preparation. In the present study, WC-12Co and WC-17Co coatings were deposited on AZ91D samples prepared using laser texturing as substrate preparation technique. Laser textured substrate was characterized using scanning electron microscopy and surface roughness tester. Bond strength of the coating was determined using ASTM 633C pull off test. SEM was used to study the morphology of the coating; XRD/EDAX techniques were used to study the structure of the coatings. Porosity and micro-hardness of the coatings were also measured. Corrosion performance of the coatings was determined using Potentiodynamic and EIS electrochemical corrosion testing techniques. The coatings are found to have good surface and mechanical properties. Both WC-12Co and WC-17Co demonstrated good corrosion performance during electrochemical testing. However, WC-12Co was found to better protect the AZ91D compared to WC-17Co.

The Electrochemical Corrosion Behavior of HVOF Sprayed Coatings

2000 ◽  
Author(s):  
A.J. Sturgeon ◽  
D.C. Buxton
Keyword(s):  
Corrosion Behavior ◽  
Thermal Spraying ◽  
Electrochemical Corrosion ◽  
Immersion Test ◽  
Corrosion Performance ◽  
Hvof Spraying ◽  
Electrochemical Testing ◽  
Electrochemical Corrosion Behavior ◽  
Immersion Testing ◽  
Sprayed Coatings

Abstract Thermal spraying of corrosion resistant alloys onto low alloy steel substrates has received much attention as a method to protect against corrosion in seawater or corrosive solutions, such as mineral or organic acids. The need to ensure high coating quality with minimal porosity and cracking, and with low oxide levels is best achieved in metallic alloys using the high velocity oxyfuel (HVOF) spraying process. This article investigates the electrochemical corrosion behavior of HVOF sprayed coatings, covering coating preparation and characterization, immersion testing, and electrochemical testing. The discussion provides information on immersion test results, polarization plots for coatings, comparison of corrosion performance, influence of microstructure on corrosion performance, and comparison with bulk alloy materials. The results reported in this article have been selected to demonstrate the use of the cyclic potentiodynamic polarization method to rank the corrosion performance of HVOF sprayed Ni-alloy coatings.

Effect of Composite Master Alloy on Mechanical Properties and Electrochemical Corrosion of ZL101 Alloy

2013 ◽  
Vol 749 ◽  
pp. 407-413
Author(s):  
Hong Xu ◽  
Xin Zhang ◽  
Ji Ping Ren ◽  
Min Peng ◽  
Shi Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Grain Refinement ◽  
Master Alloy ◽  
Mass Fraction ◽  
Electrochemical Corrosion ◽  
Corrosion Performance ◽  
Obvious Effect ◽  
Mechanical Properties And Corrosion

The mechanical properties and corrosion performances of the ZL101 alloy modified by the composite master alloy were investigated. The results showed that the master alloy had not only obvious effect of grain refinement, but also a significant role in refining dendrite grain of ZL101 alloy. The grain size decreased dramatically from 150μm to 62μm when the addition of composite master alloy is up to 0.5%(mass fraction) and the temperature is 720 for 30 minutes,. Its tensile strength and elongation increased by 27% and 42% respectively. The grain refinement of ZL101 alloy decreased its corrosion performance. The morphology of Si changed into globular from needle modified by NaF, instead of AlTiB.

In-Vitro protein digestibility, physico-chemical properties and nutritional quality of sorghum-green gram cookies supplemented with mango powder

2021 ◽  
pp. 39
Author(s):  
Keyword(s):  
Nutritional Quality ◽  
Chemical Properties ◽  
Protein Digestibility ◽  
Vital Role ◽  
Green Gram ◽  
In Vitro Protein Digestibility ◽  
Physico Chemical ◽  
Thiamine Content ◽  
Vitro Protein

Ready to Eat (RTE) sorghum cookies were prepared by incorporating green gram flour at 10%, 20%, 30%, dried mango powder at 10% and evaluated for their physico-chemical and nutritional properties. Protein, fat, fiber and ash increased with increase in green gram flour substitution as carbohydrate content decreased significantly. Significant differences (p ≤ 0.05) in protein content were seen in cookies ranging from 9.52% to 13.60%. Fiber increased significantly from 9.40% to 10.90%. In vitro protein digestibility ranged from 67.75 ± 0.01% to 90.05 ± 0.10 %. Vitamins analysed increased with addition of green gram flour. Thiamine content ranged from 0.22±0.02 to 0.61±0.02 mg/100g, riboflavin from 0.09±0.00 to 1.39±0.04 mg/100g and ascorbic acid from 13.87±0.79 to 19.31±0.94 mg/100g. Value addition of under-utilized crops like sorghum and green grams can play a vital role in development of high nutritional quality RTE products.

Effect of Dealloying Process on Microstructure and Electrochemical Properties of Ni Foam

2018 ◽  
Vol 922 ◽  
pp. 3-7
Author(s):  
Guang Ya Hou ◽  
Ji Yu Li ◽  
Lian Kui Wu ◽  
Yi Ping Tang ◽  
Hua Zhen Cao ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Electroless Plating ◽  
Electrochemical Etching ◽  
Nickel Foam ◽  
Chemical Properties ◽  
Ni Foam ◽  
Electrochemical Testing ◽  
Cu Alloy ◽  
Hierarchical Pore ◽  
Counter Diffusion

Ni foam with 3D porous structure has attracted attention in the field of catalysis. Expanding the specific surface area of Ni foam is an important method to enhance its chemical properties. In this study, the Cu-Ni/Ni foam were obtained by electroless plating copper on Ni foam and then heat treatment for homogenizing at 750°C. The dealloying of the Cu-Ni/Ni foam was carried out by electrochemical etching for obtaining the Ni foam with hierarchical pore structure. The microstructure, phase and electrochemical performance were characterized by SEM, XRD and electrochemical testing. The results showed that the optimized temperature of electroless plating Cu on Ni foam is 60oC. Ni-Cu alloy can be obtained by counter diffusion above 750°C. With prolonging time of etching, the content of Cu component decreased and the size of pores on the sturts of the Cu-Ni/Ni foam changed from nano to micro scale. The electrochemical properties of the alloywere significantly higher than that of the pure nickel foam.

Oxidation and electrochemical corrosion performance of Ti3Al alloy with TiAl coating

2010 ◽  
Vol 57 (1) ◽  
pp. 13-17
Author(s):  
Yan Jun Xi ◽  
Yong Jun Liu ◽  
Zhi Xin Wang ◽  
Jin Bin Liu
Keyword(s):  
Electrochemical Corrosion ◽  
Corrosion Performance ◽  
Ti3al Alloy

scholarly journals Study of Microstructural and Corrosion Properties of Aluminium Alloy 7075 after Plasma Nitriding

2020 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
Haerul Ahmadi ◽  
Rizky Abdul Aziz ◽  
Suprapto Suprapto ◽  
Tjipto Sujitno ◽  
Sophie Hapsari
Keyword(s):  
Aluminium Alloy ◽  
Plasma Nitriding ◽  
White Layer ◽  
Chemical Properties ◽  
Electrochemical Corrosion ◽  
Corrosion Testing ◽  
Raw Material ◽  
Corrosion Properties ◽  
Structural Part ◽  
And Chemical Properties

Plasma nitriding is a treatment process of metals by depositing nitrogen into metal that considered to be nitrided by mean of increasing the mechanical, physical, and chemical properties of the metal. This treatment will form a hard layer compund of Al-N on the surface of the sample. In this study, aluminium alloy 7075 was nitrided which the application of it to structural part of aircraft makes it vulnarable to not only corrosion and wear attack but also decreasing the hardness of the material. One method to overcome these issues is plasma nitriding. The purpose of of this research is to do the characterizations of plasma nitrided aluminium alloy 7075 regarding its microstructure, mechanical, and chemical properties. The characterizations that had been done were microhardness Vickers testing, SEM-EDX, and electrochemical corrosion testing Potensiostat. The hardness of the sample increased 55% from 75,88 VHN (raw material) to 117,68 VHN (at optimum parameter). The depth of the white layer of plasma nitriding is approximately 6 µm, while the EDX result reported carbon, oxygen, and nitrogen presence. Corrosion testing showed that the highest corrosion rate is on the raw material, 0,15393 mpy. While the optimum one is 0,07184 mpy.

scholarly journals Fabrication and Investigation of Al2024-B4c-Tic Hybrid Metal Matrix Composites using Laser Beam Machining

2020 ◽  
Vol 12 (3) ◽  
pp. 229-234
Author(s):  
S. SURESH KUMAR ◽  
Anish NAIR ◽  
G. Praveen MUTHU KUMAR ◽  
V. MUTHU KRISHNAN ◽  
M. RAMESH KANNA
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Vital Role ◽  
Machining Process ◽  
Surface Finishing ◽  
Aviation Industry ◽  
Matrix Composites ◽  
Beam Laser ◽  
Good Surface ◽  
The Impact

The use of unconventional machining technique for Aluminum based Metal Matrix Composites [MMCs] are generated considerable interest in machining. In the aviation industry, in order to obtain a high precision, a good surface finishing and high working speed, the processing of these hard materials is done with the help of the fiber beam laser). The objective is to determine the mechanical properties of the hybrid composite and further investigate its machinability. The aerospace industry uses the laser machining for its machining process like drilling the cooling holes etc. Standard frequency and variation in other parameters such as pulse width, power, and time will occur the impact in the laser beams composites like diameter and roundness of the hole. Especially, the increase in the variation of power and time plays a vital role in the diameter and roundness of the hole.

scholarly journals Computing Analysis of Zagreb Indices for Generalized Sum Graphs under Strong Product

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Muhammad Javaid ◽  
Saira Javed ◽  
Abdulaziz Mohammed Alanazi ◽  
Majdah R. Alotaibi
Keyword(s):  
Chemical Engineering ◽  
Chemical Properties ◽  
Chemical Compounds ◽  
Vital Role ◽  
Molecular Structures ◽  
Zagreb Indices ◽  
Graph Theoretic ◽  
Strong Product ◽  
Physicochemical And Structural Properties ◽  
Product Of Graphs

Numerous studies based on mathematical models and tools indicate that there is a strong inherent relationship between the chemical properties of the chemical compounds and drugs with their molecular structures. In the last two decades, the graph-theoretic techniques are frequently used to analyse the various physicochemical and structural properties of the molecular graphs which play a vital role in chemical engineering and pharmaceutical industry. In this paper, we compute Zagreb indices of the generalized sum graphs in the form of the different indices of their factor graphs, where generalized sum graphs are obtained under the operations of subdivision and strong product of graphs. Moreover, the obtained results are illustrated with the help of particular classes of graphs and analysed to find the efficient subclass with dominant indices.

scholarly journals The Influence of Glass Flake and Micaceous Iron Oxide on Electrochemical Corrosion Performance of Waterborne Silicate Coatings in 3.5% NaCl Solution

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 833 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Zhanping Zhang ◽  
Kejiao Li
Keyword(s):  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Impact Resistance ◽  
Electrochemical Corrosion ◽  
Nacl Solution ◽  
Corrosion Performance ◽  
Pencil Hardness ◽  
Anticorrosive Pigments ◽  
Comprehensive Comparison ◽  
Glass Flake

Waterborne silicate composite coatings were prepared to replace existing solvent-based coatings for ships. A series of complex coatings were prepared by adding anticorrosive pigments to the silicate resin. Adhesion, pencil hardness, and impact resistance were investigated, and corrosion performance in 3.5% NaCl solution was measured by electrochemical impedance spectroscopy (EIS). The results show that adhesion and impact resistance are high, and that pencil hardness can reach 4H. The curing mechanism for the coatings were investigated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The mechanism of curing reaction in the studied waterborne silicate paint was found to be different from that reported in the literature. When the coatings were immersed in 3.5% NaCl solution for 8 h, there is only one time constant in the Bode plot, and coating capacitance (Qc) gradually increases while coating resistance (Rc) gradually decreases. Glass flake composite coatings have better corrosion resistance by comprehensive comparison of Qc and Rc.

scholarly journals Discoloration Resistance of Electrolytic Copper Foil Following 1,2,3-Benzotriazole Surface Treatment with Sodium Molybdate

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 427 ◽  
Author(s):  
Dong-Jun Shin ◽  
Yu-Kyoung Kim ◽  
Jeong-Mo Yoon ◽  
Il-Song Park
Keyword(s):  
Surface Treatment ◽  
Photoelectron Spectroscopy ◽  
Copper Foil ◽  
Deposition Time ◽  
Film Formation ◽  
Electrochemical Corrosion ◽  
Sodium Molybdate ◽  
Surface Characteristics ◽  
Protective Film ◽  
Electrolytic Copper

The copper which an important component in the electronics industry, can suffer from discoloration and corrosion. The electrolytic copper foil was treated by 1,2,3-benzo-triazole (BTA) for an environmentally friendly non-chromate surface treatment. It was designed to prevent discoloration and improve corrosion resistance, consisted of BTA and inorganic sodium molybdate (Na2MoO4). Also the ratio of the constituent compounds and the deposition time were varied. Electrochemical corrosion of the Cu-BTA was evaluated using potentiodynamic polarization. Discoloration was analyzed after humidity and heat resistance conditioning. Surface characteristics were evaluated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Increasing corrosion potential and decreasing current density were observed with increasing Na2MoO4 content. A denser protective coating formed as the deposition time increased. Although chromate treatment under severe humidity (80% humidity, 80 °C, 100 h) provided the highest humidity resistance, surface treatment with Na2MoO4 had better heat discoloration inhibition under severe heat-resistant conditions (180 °C, 10 min). When BTA reacts with Cu to form the Cu-BTA-type insoluble protective film, Na2MoO4 accelerates the film formation without being itself adsorbed onto the film. Therefore, the addition of Na2MoO4 increased anticorrosive efficiency through direct/indirect action.

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