Directed Regulation and Localization of Electrical Properties for Composite Construction Materials

Research results of modified composites which consist of isolated layers with different properties and their practical usages are represented in this article. A structure of the composite material is considered. The structure is combined of few layers; external layers are made of corrosive resistance material with dielectric behavior while the internal part of the composite is made of electrically conductive material with high conductive and mechanical properties. Conductive properties of each layer have been measured as well as their mechanical properties and structure. Also, the features of the joints between layers in terms of structure and properties were defined. More than that, varieties of mixtures and their possible usage are considered. Conductive properties of composite materials and ways of their adjustment have been described as well. For the first time, the measuring scheme of conductive properties for each layer was offered and heat shrinkable tubes and copper electrodes were used for it. Efficiency of modified composites and its behavior when electrical current applied can be measured by using the scheme.

Sustainable Corrosion Inhibitors for Copper and its Alloys

The good properties of copper, as well as its alloys, make them a often used metallic materials in various industries. Regardless of their excellent corrosive resistance, the corrosion process of copper materials can occur under some specific conditions, hence, the need for corrosion inhibitors. Recently, due to many environmental agencies, the “green” aspect was introduced in many fields, including inhibition of corrosion. Keeping in mind economic and eco-friendly aspects, a wide range of compounds were employed as ecological inhibitors for copper materials. For this purpose, the current chapter aims to explore the application of numerous compounds as sustainable inhibitors to control the corrosion of copper materials in various media.

Towards Mg based light materials of future: Properties, applications, problems and their mitigation.

The use of lighter materials is one of the efficient means to mitigate the increasing demands on fuel resources, reduce CO2 emissions. Mg is one of the lightest material available and possesses exciting range of properties such as low density and high strength to weight ratio. Despite such exciting properties, the applications of Mg and its alloys were very limited in aerospace, automotive and biomedical industries but recently the application is picking-up. The restricted application is attributed to anisotropy, poor corrosive resistance and inflammability of Mg. The current review addresses the barriers limiting the widespread application of Mg based materials. Furthermore, the mitigation of the problems of anisotropy, poor corrosion resistance, ductility and inflammability of Mg are critically reviewed. The findings of this research provide insights of the processing techniques, properties and how to address the potential barriers of limited applications. The review paper will assist and motivate the researchers to ponder and overcome numerous problems related to Mg and its alloys by understanding the importance of each problem discussed in this review. An attempt has also been made to arrange research status on issues and the mitigation thereof with respect to Mg and its alloys as single reference point.

An overwiew on corrosion behavior of steels in factory

In this study, corrosion behaviors of diffuser unit solution by which raw sugar is produced from minced sugar beets in sugar factories on St-37 low alloy steel and AISI 304, 304L, 316 austenitic stainless steel types were examined. Moreover, influence of heat treatment on corrosion resistance was investigated. Corrosion tests were performed using mass loss method. SEM-EDX, X-rays Diffraction, microhardness and surface hardness analyses of samples were carried out. As a result, it was determined that AISI 304L and 316 steels have better corrosive resistance and heat treatment improves corrosion resistance.

Multifunctional layered composite material used for construction purposes

Introduction. The adjustability of electrical properties of materials, that have hydraulic setting characteristics, has been studied over the last decades. It is emphasized that any change in electrical properties, triggered by various additives, causes negative side effects, including low corrosive resistance and modified physical and mechanical characteristics. The purpose of this research is to design a multifunctional layered material that features localized electrical conductivity. The objective is to track the influence of modifiers, capable of regulating electrical properties. Materials and methods. Samples were made of Portland cement I 42.5; the cement, having the fineness modulus of 0.7, was used as the aggregate; samples also contained ground Sulphur type 9998 (GOST 127.1-93), soot slurry, and calcium nitrate. The co-authors have identified the unit resistance values of each layer of this composite material, mechanical properties and features of each layer, and the structure of contact layers. Results. The co-authors have determined that the addition of pre-treated Sulphur in the amount of 7 % of the binder mass facilitates the formation of a nonconductive layer, whose unit resistance reaches 29.57 kiloohm cm on the 28th day. The conductive layer, generated by adding soot in the amount of 7 % of the binder mass, ensures the stable passage of electric current. The co-authors have identified that calcium nitrate influences the morphology of secondary crystalline hydrates and the non-crystalline phase of the mineral matrix, made of Portland cement, and it also ensures the required concrete strength. Conclusions. The layered method of formation of new compositions allows to make composite materials having adjustable electrical characteristics. New materials are made of Portland cement, and they contain no non-conductors. The co-authors have proven the efficiency of Sulphur, an integrated modifier made of soot and calcium nitrite, used as the modifiers of the mineral matrix, since they regulate the electrical properties of the artificial stone.

Microbial-Induced Corrosion of 3D-Printed Stainless Steels: A Surface Science Investigation

Stainless steel is a material manufactured for its high corrosive resistance and is the first choice of material in a range of applications. Microbial-induced corrosion can cause significant damage to metals and is responsible for approximately 20% of corrosive damage. The corrosive resistance of stainless steel is reduced during manufacturing processes, including welding or joining methods, as the connection points prevent the metal from reforming its passivation layer. Additive manufacturing processes allow for intricate designs to be produced without the need for welding or bolts. However, it is unknown how the layering method of additive manufacturing (AM) will affect stainless steel’s passivation layer and, in turn, its corrosive resistance. This research compares the corrosive resistance of 316L stainless steel produced using laser metal deposition and traditionally manufactured AISI 316 stainless steel to determine how the layering manufacturing method affects the corrosive resistance of the material. Samples are incubated over a 21-day period with Acidithiobacillus ferrooxidans (A.f) and Leptospirillum ferooxidans (L.f) in a modified HH medium with an approximate pH of 1.8 and kept at a constant temperature of 30 °C. Scanning electron microscopy and Auger electron spectroscopy surface analysis techniques are used to identify any corrosive processes on the surface of the samples. This research is an introductory analysis of the corrosive resistance of AM 316 stainless steel using the laser metal deposition technique. The results show how stainless steel produced using laser metal deposition will react in acidic environments and are used to determine if it could be used in conjunction with other materials in underground pipes for acidic soils.

Analysis & Optimization of Parameters During EDM of Aluminium Metal Matrix Composite

In now days Aluminium Metal Matrix Composite (AMMC) has become one of the most favorite material for automotive, aerospace, shipyard etc. industry because of their outstanding properties such as high wear and corrosive resistance, remarkable hardness and toughness, low density, light weight etc. But because of the complexity of the cutting geometry and mechanical properties of work materials the use of convectional machining process becomes limited. Such difficulties are easily sort-out by using electric discharge non convectional machining process (EDM) because in this case material removal takes place by thermal erosion process. The present research work highlight the effect of process parameter on output response during the EDM of Aluminium7075- Boron carbide-Graphite (Al/B4C/Gr) metal matrix composite (MMC). Taguchi technique is used for design of experiments. Fitness and adequacy of the experimentation has tested through the analysis of variance (ANOVA).

Weldability of duplex stainless steels- A review

Duplex stainless steel finds widespread use in various sectors of manufacturing and related fields. It has many advantages due to its distinctive structural combination of austenite and ferrite grains. It is the need of the current generation due to its better corrosive resistance over high production austenitic stainless steels. This paper reviews the weldability of duplex stainless steels, mentions the reason behind the need for duplex stainless steels and describes how it came into existence. The transformations in the heat-affected zones during the welding of duplex stainless steels have also been covered in this paper. The formation, microstructure and changes in high temperature and low temperature heat-affected zones have been reviewed in extensive detail. The effects of cooling rate on austenite formation has been briefly discussed. A comparison of weldability between austenitic and duplex stainless steel is also given. Finally, the paper reviews the applications of the various grades of duplex stainless steel in a variety of industries like chemical, paper and power generation and discusses the future scope of duplex stainless steel in various industrial sectors.

Assessment of the destructive influence of sanitary cleansing on pharmaceutical rubber stoppers using a method of measuring the contact angle

For the first time, experimental studies of the influence of sanitary cleansing on the surface of pharmaceutical rubber (butyl- and halobutyl-based) stoppers were carried out by measuring the contact angle. It was found that the sanitary cleansing of stoppers, carried out before the closure of sterile dosage forms of medicinal products (MP), including pre-sterilization cleaning of the stoppers (2-fold boiling for 30 min in 1% solution of trisodium phosphate or sodium hydroxide and a single boiling in 0.1% solution of hydrochloric acid for 30 min) and subsequent sterilization in an autoclave at t = 130°C, pressure p = 0.2 MPa for 60 min acts destructively on their surface and is accompanied by a decrease of the contact angle (an increase in the hydrophilicity of the stoppers’ surface), which leads to significant leaching of the components of rubber stoppers and their contamination of drug solutions. Determination of the contact angle allows by reproducible instrumental method to identify and quantify the destruction processes of the surface of rubber stoppers used for closing of sterile solutions of MP. This indicator can be used to assess the influence of pharmaceutical and technological factors (sanitary cleansing, sterilization, contact with drug solutions, etc.) on the rubber stoppers surface, to control the corrosive resistance of closures and to predict the amount of impurities in sterile solutions of MP.

A review of composite leaf springs for automotive vehicles

In the quest to conserve natural resources and economic energy. Weight reduction has been the focus of auto-manufactures and the aerospace industry in the present day. Weight reduction can be archived primarily by introducing better design optimization, better material, and improved manufacturing processes. This approach by introducing composite materials into automobile industries, which has high strength to weight ratio and excellent corrosive resistance, can fulfil the requirement. This review paper investigates the use of composite materials in the design of leaf springs for automotive vehicles. The paper underscores the suitability of composite materials for leaf spring in automobiles and develops a new leaf spring design that optimizes weight reduction and strength. The review provides details regarding previous efforts conducted on the design of leaf springs while outlining the knowledge gap areas. This review commences with an introduction to leaf springs and a brief history of their development. Followed by the properties that make an excellent leaf spring, this helps narrow down the information required for further developments providing avenues for possible future research.