Surfaces, Coatings and FilmsCondensed Matter PhysicsConservationMaterials ChemistrySurfaces and Interfaces
Phân tích ảnh hưởng
Thông tin về tạp chí
Surface Engineering provides a forum for the publication of refereed material on both the theory and practice of this important enabling technology, embracing science, technology and engineering. Coverage includes design, surface modification technologies and process control, and the characterisation and properties of the final system or component, including quality control and non-destructive examination.
Responses of welded joint of carbon steel to surface mechanical attrition treatment (SMAT) and shot peening (SP) were investigated. Experimental evidences showed that the microstructure of treated surface in the welded joint by means of SMAT was characterised by nanometre grains of about 13·6 nm in size and that of SP was characterised by highly dense dislocation configuration. The similar microhardness profiles with different peak values in the top surface were observed for three typical zones of welded joints processed by SMAT and SP. Compared with as welded specimens, SMAT and SP processes have improved the fatigue strength by as much as 61 and 36·3% respectively based on fatigue life 2×106 cycles. The observed enhanced fatigue behaviours of the welded joint processed by SMAT and SP should be attributed to the combined influences of compressive residual stress, work hardening, nanostructure and elimination of microdiscontinuities in the vicinity of welded joints.
I. Neelakanta Reddy, V. Raghavendra Reddy, Arjun Dey, N. Sridhara, S. Basavaraja, Parthasarathi Bera, C. K. Aanandan, Anand Sharma
Alumina thin films of different thicknesses, e.g. 90, 120 and 150 nm, were grown on SS304 thin foil by electron beam evaporation technique. The films were post-heat treated at 500, 700 and 800°C in air and subsequently characterised by X-ray diffraction, atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of thicknesses and post-heat treatment on microstructure have been studied. The deposited alumina film was almost stoichiometric. The alumina film of the lowest thickness, i.e. 90 nm post-heat treated at 700°C, showed preferential growth of nanorods and irregular polygonal nanostructures with random orientation.
The compound layer of iron nitrides (white layer) and the diffusion layer formed during the nitriding of an austenitic stainless steel have been investigated by a combination of optical and electron microscopy and X-ray powder diffraction. The mechanical behaviour of the nitrided surface is controlled by the microstructure, which is shown to be dictated by the nitriding temperature and cooling rate from that temperature. The results provide a complete description of the phase distribution in the nitrided case and indicate the nitriding conditions required to achieve a wide range of properties, from surface hardening to deliberate embrittlement.
F.M. El-Hossary, Fadhil Muhi Mohammed, A. Hendry, D.J. Fabian, Z. Szaszne-Csih
A novel radio frequency (rf) plasma technique for nitriding engineering steels is described whichproduces a surface layer of exceptional hardness in extremely short nitriding times. The sample does not form part of the primary electrical circuit, as is the case, with de plasma methods, and the temperature at the metal surface is controlled by a variable pulsed mode operation of the inductively coupled nitrogen plasma. The rate of nitriding is compared to those obrained by conventional ammonia nitriding and by de plasma methods. The rapid rates of layer growth observed with the rf plasma are discussed in terms of an interstitial–vacancy coupled diffusion model. The results demonstrate the feasibility of a rapid and flexible process for nitriding all grades of engineering steels.
This study deals with the oxidation of methanol in alkaline media. For this purpose, first nickel and nickel–platinum particles were deposited on carbon paper substrates by using electroplating with galvanic deposition method. Then the morphology of the metal particle coatings on the carbon paper was studied by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The catalytic properties of the electrodes for methanol oxidation were studied using electrochemical methods such as cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The results showed higher catalytic activity of the Ni–Pt/carbon paper electrode compared with the Ni/carbon paper electrode. Therefore, Ni–Pt/carbon paper electrode is a good candidate as an anode for direct methanol fuel cells.
Platinum and nickel–copper nanoparticles were electrodeposited on glassy carbon electrode (GCE) by using cyclic voltammetry (CV)-based electroplating technique. Morphology and chemical composition of the newly designed electrode was studied via scanning electron microscope, energy dispersive X-ray and elemental mapping analysis. This electrode was eventually employed to electro-oxidation of glucose using CV, chronoamperometry (CA) and electrochemical impedance spectroscopy techniques. Pt–Ni–Cu/GCE is capable of electro-oxidation of glucose at a low potential and generating high peak current density. The results of CV and CA revealed the high catalytic activity of the Pt–Ni–Cu/GCE and steady-state activity for glucose electro-oxidation. Compared to the other electrodes reported in the previous literature, Pt–Ni–Cu/GCE shows a better potential as an anode. Low electrochemical charge transfer resistance ( Rct) is of particular advantages for the Pt–Ni–Cu/GCE. This electrode is a good choice as an anode for application in direct glucose alkaline fuel cells.
Magnesium and its alloys are fascinating candidates for biodegradable implants due to their suitable mechanical properties, biodegradability and biocompatibility. However, the rapid corrosion rate, generation of a large amount of hydrogen gas and increase in local pH of the body fluid limit their potential biomedical applications. Various techniques, including alloying, mechanical processing and surface treatment, have been used to reduce the corrosion rate of materials. Surface treatment is one of the widely used techniques to improve the corrosion resistance of the Mg alloys. Compared to other surface modification processes, micro-arc oxidation can provide good adherent, hard, scratch-resistant, wear-resistant, and corrosion-resistant coatings on magnesium alloys. This article mainly reviews the influence of key relatively process parameters, such as electrolytic composition and presence of additives. Normally, electrolytic system and additives can improve the corrosion behaviour of magnesium alloys using appropriate concentration. The future prospects are summarised as well.
A series of commercially available cemented carbides coated with single or composite layers of TiC, TiN, and Al2O3 were used to cut three types of steel, En 8 (080M40), En9 (070M55), and En24 (817M40). For comparison, two uncoated cemented carbides and some Al2O3-ceramic inserts were also tested. The worn surfaces were examined using optical and scanning electron microscopy techniques and tool/work interfacial conditions were evaluated from ‘quick stop’ experiments and tool temperature estimates. By linking this information with observed wear rates, various rake and flank wear mechanisms are proposed.
Chỉ số ảnh hưởng
Các tạp chí khác
Tạp chí Khoa học Tự nhiên Đại học Quốc gia Thành phố Hồ Chí Minh
Tạp chí Khoa học Kiểm sát
Tạp chí Khoa học Kiến trúc và Xây dựng
Tạp chí Nghiên cứu Khoa học và phát triển Trường Đại học Thành Đô
Tạp chí Khoa học - Công nghệ trong lĩnh vực An toàn thông tin
Tạp chí Phát triển Khoa học và Công nghệ Đại học Quốc gia Thành phố Hồ Chí Minh