Effect of the variation of the electrodeposition time of hydroxyapatite/chitosan coatings on AISI 316L SS

Type AISI 316 L Stainless Steel (316 L SS) plays a crucial role in bone replacement surgery due to its excellent mechanical features, availability at low cost, and ease of fabrication, but its performance is low when in contact with the aggressive conditions of the human body fluids. Chitosan (CTS) is a biopolymer that blended with hydroxyapatite (HAp) could form coatings to improve surface properties of a metallic orthopedic prosthesis, i.e., corrosion-resistance to the base metal and biocompatibility of the ceramic on the metal surface. This work aims to obtain and evaluate HAp/CTS composite coatings deposited on the surface of AISI 316 L SS substrate by electrophoretic deposition (EDP) technique. The influence of the time of deposition on the coating’s characteristics and properties was characterized and discussed. The coatings were structural, elemental, and chemically characterized using X-Ray diffraction and Raman spectroscopy. HV values in a range of 64.7 to 111.5 were observed, showing the lowest HAp/CTS-30.0 coating values for all the loads applied. The lowest HV value was nearby to the reported value for human bone’s hardness, around 47HV; considering that the coating will be in constant contact motion with the bone surface, the contact with a softer surface could decrease the wear on the human bone. The hardness decreases with the coating thickness’s increment because the coating presented a higher plastic deformation than the 316 L SS surfaces. A decrease in the roughness average (Ra) was well noticed as the deposition time increased; meanwhile, the thickness increased as the deposition time increased.

Duplex stainless steel of type UNS S32101 and ferritic stainless steel of type AISI 430 subjected to cathodic hydrogenation

This work presents a study on the duplex stainless steel UNS S32101 and ferritic AISI 430 when subjected to cathodic hydrogenation, to ascertain their behavior under the action of hydrogen. Throughout the research, with the aid of optical (MO), scanning electronics (SEM) and atomic force (AFM) microscopy, both hydrogen embrittlement and pitting corrosion after hydrogenation and degassing in UNS S32101 duplex stainless steel became evident. Subsequently, the X-ray diffraction performed to verify the phase transformations confirmed the transformation of the austenitic phase into the martensitic phase in the duplex steel and confirmed the formation of Cr23C6 precipitates in the ferritic steel. And so, it corroborated with the SEM images, proving the transformation of σ-phase agent of pitting corrosion in duplex steel.

Numerical and Experimental Explorations for the Formability of Drawing Square Cups Through Deep Drawing Operation (January 2020)

This study aims to examine the formability of drawing cups having square shapes through direct deep drawing process on a single action press through one pass. This can be accomplished by conducting an FE simulation and performing an experimental investigation on steel substrate type AISI 1008 blank with diameter and thickness dimensions 80, 0.5 mm respectively. To explore and analyze the formability of such a drawing process, two process parameters have been included in this work which is the speed of punch (30 and 300 mm/min) and the lubrication state (with machine oil and dry drawing). Both direct and indirect measurements of thickness strain have been adopted as an indicator of the sheet formability. The results of both FE simulation and experimental work demonstrate that the square drawing of the AISI sheet has been accomplished for all the four cups produced since the highest thinning over the cup wall does not exceed 25% of the original thickness. Generally, there is a good match between the experimental values of the indirect method and the FEM results for all models such that the largest deviation is about 25%. The direct method of thickness measurement is determined to be non-confident as strain values are practically unacceptable. Additionally, higher formability of the sheet has been realized at lower punch speeds. Furthermore, no significant difference has been observed in the formability at both speeds of punch when using a lubricant compared to the dry drawing operation.

Optimization of Diffusion Bonding of Pure Copper (OFHC) with Stainless Steel 304L

This work deals with determination of optimum conditions of direct diffusion bonding welding of austenitic stainlesssteel type AISI 304L with Oxygen Free High Conductivity (OFHC) pure copper grade (C10200) in vacuum atmosphere of (1.5 *10-5 mbr.). Mini tab (response surface) was applied for optimizing the influence of diffusion bonding parameters (temperature, time and applied load) on the bonding joints characteristics and the empirical relationship was evaluated which represents the effect of each parameter of the process. The yield strength of diffusion bonded joint was equal to 153 MPa and the efficiency of joint was equal to 66.5% as compared with hard drawn copper. The diffusion zone reveals high microhardness than copper side due to solid solution phase formation of (CuNi). The failure of bonded joints always occurred on the copper side and fracture surface morphologies are characterized by ductile failure mode with dimple structure. Optimum bonding conditions were observed at temperature of 650 ◦C, duration time of 45 min. and the applied stress of 30 MPa. The maximum depth of diffuse copper in stainless steel side was equal 11.80 µm.

Analisis Variasi Included Angle terhadap Distorsi pada Sambungan Las SMAW

The aim of this study is to determine the effects of included angle dimension on the distortion of carbon steel V-groove butt joint using a single pass welding methods. Specimens being studied were AISI 1025 low carbon steel in the form of 1/2 inch-thick plates. The steels were easily weld and were assumed as homogeneous and isotropic; therefore, three specimens for each treatment are adequate. The experiment treated the v-groove shape as independent variable and the distortion as dependent variable. The results show that there is an effect of v-groove dimensions on the distortion of the carbon steels butt joint.. The distortion and their respective angle dimensions are 0.58˚ for the 55˚ angle, 0.78˚ for the 60˚ angle, and 1.02˚ for the 65˚ angle. The magnitude of the distortions are well below 3˚, which is the permissible amount for the butt joint distortion criteria.Tujuan penelitian ini untuk mengetahui ada tidaknya pengaruh dimensi included angle (bentuk kampuh) terhadap distorsi pada sambungan ujung baja karbon dengan metode pengelasan SMAW single pass. Dalam penelitian ini obyek yang diteliti adalah baja karbon rendah type AISI 1025 yang berupa plat strip dengan ketebalan 1/2 inchi. Baja jenis ini merupakan bahan yang mudah dilas dan diasumsikan homogen dan isotropic, sehingga sampel yang diambil cukup tiga buah pada masing-masing perlakuan. Bentuk included angle merupakan variabel bebas dan distorsi adalah variabel terikat. Hasil penelitian menunjukkan adanya pengaruh dimensi included angle terhadap distorsi pada sambungan ujung baja karbon. Besarnya distorsi pada sambungan dengan dimensi sudut 55˚ sebesar 0,58˚, 60˚ sebesar 0,78˚, 65˚ sebesar 1,02˚. Hal ini memberikan informasi bahwa variasi sudut included angle tersebut menghasilkan distorsi di bawah 3˚, sehingga masih termasuk dalam batas yang diijinkan persyaratan kelolosan sambungan las.

Temperature behaviour on deposition of the titanium nitride thin films on the H13 steel by the electric arc discharge in vacuum

Objective: In this present research work the behaviour of temperature of the substrate manufactured in AISI H13 steel, in the range of and , during of surface deposition of titanium nitride (TiN) thin films by the technique of cathodic arc in vacuum. Results: The physical properties of the TiN films were obtained and analysed by the techniques of micro-indentation, Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD). Conclusion: It was determined that the increase in the temperature of the substrate during the deposition of TiN films improves the mechanical properties of the surface of the steel of type AISI H13, where the highest hardness was present in the coating deposited at a temperature of , which has a preferential orientation in the plane determined by the XRD patterns.Keyword: Coatings, Metal substrates, Substrate temperatureResumenObjetivo: En el presente trabajo de investigación se estudia el comportamiento de la temperatura del sustrato, fabricado en acero de tipo AISI H13, en el rango de y , durante la deposición superficial de películas delgadas de nitruro de titanio (TiN) por la técnica de arco catódico en vacío. Resultados: Las propiedades físicas de las películas de TiN fueron obtenidas y analizadas mediante las técnicas la micro-indentación, microscopía de fuerza atómica (AFM) y la difracción de rayos x (DRX). Conclusión: Se determinó que el incremento en la temperatura del sustrato durante la deposición de las películas de TiN, mejora las propiedades mecánicas de la superficie del acero de tipo AISI H13, donde la mayor dureza se presentó en el recubrimiento depositado a una temperatura de , el cual tiene una orientación preferencial en el plano determinada por los patrones de DRX.Palabra Clave: Revestimientos, Sustratos metálicos, Temperatura del sustrato Resumo Objetivo: No presente pesquisa é estudado o comportamento da temperatura do substrato, feito de aço de tipo AISI H13, no intervalo de e , durante a deposição superfície das películas finas de nitreto de titânio (TiN) por meio da técnica de arco catico em vácuo. Resultados: As propriedades físicas dos filmes de TiN foram obtidos e analisados pelas técnicas de micro-indentação, microscopia de força atómica (AFM) e difracção de raios-X (DRX). Conclusão: determinou-se que o aumento de temperatura do substrato durante a deposição do filme de TiN, melhora as propriedades mecânicas da superfície do aço de tipo AISI H13, onde a maior dureza foi apresentada no revestimento depositado a uma temperatura de , que tem uma orientação preferida no plano determinados pelos padrões de DRX.Palavras-chave: Revestimentos, Substratos metálicos, Temperatura do sustrato