Manuela Cristina Perju

By Petrică Vizureanu, Manuela-Cristina Perju, Dragoş-Cristian Achiţei and Carmen Nejneru

This chapter will study the material base-surface multilayer system for various types of depositions (increasing the wear resistance of Fe-C alloy parts) whose compatibility with the substrate provides high-quality parts. Thus, this system of layers can be applied on both the new and worn parts, being able to recondition and reintroduce in an intensive exploitation regime any parts with complex configuration operating in dynamic conditions. Deposited layers will be obtained using electro-spark deposition (ESD) process, which is a technology that uses electrical energy stored in a capacitor to initialize an electrical spark between the cathode and the anode. The high temperature generated by the electrical spark leads to partial melting of substrate and mixing of it with the material of the electrode. Between the two electric sparks, the amount of the molten metal solidifies to form the surface layer. The ESD is a very well used process for materials manufacturing in many industrial sectors.

Part of the book: Advanced Surface Engineering Research

By Petrică Vizureanu and Dragoș-Cristian Achiței

This chapter presents advanced researches about the using of metallic alloys with shape memory properties in construction and exploitation of parts subjected to combined stress by thermal and mechanical fatigue during their functioning. The shape memory alloys (SMAs) have a series of properties much different from the usual metallic materials. Their main characteristic is recovery/returning from plastic deformation by heating, considering that in some cases at temperature changing, the shape modification is reversible. In the case of parts made from SMA, which work in conditions by thermal and mechanical stresses and temperature variations, the resistance evaluation at thermal and mechanical fatigue is absolutely necessary. Like researching domain, regarding thermal and mechanical fatigue behavior, it was selected the shape memory Cu-based alloy. The achieved researches, concerning methodology, investigation equipment, experimental results, allow evaluating and estimating the shape memory properties. Losing the shape memory properties of SMA, in requested conditions, namely amnesia, so to the calculation of fatigue resistance must be taken into account by this fundamental property. The expression of the fatigue state, through losing the memorizing capacity, represents a designing indicator, which ensures the guaranty of properties in fatigue conditions, through applying of fatigue cycles. To determine the fatigue resistance of SMA was necessary specific requests. The properties are guaranteed for a certain number of fatigue cycles. The experimental data, presented in this chapter, offer to scientists some information about the SMAs, Cu-based. These data can be used in designing and manufacturing of new parts for different devices.

Part of the book: Shape-Memory Materials

By Petrică Vizureanu, Mădălina Simona Bălțatu, Andrei Victor Sandu, Dragos Cristian Achitei, Dumitru Doru Burduhos Nergis and Manuela Cristina Perju

Bioactive glasses are very attractive materials, used for tissue engineering materials, usually to fill and restore bone defects. This category of biomaterials, show considerable potential for orthopaedic surgery because they can promote bone tissue regeneration. Many trace elements have been incorporated in the glass network, an example is metallic glasses to obtain the desired properties. Because of tolerable mechanical properties, and because they are able to bond to living bone and stimulate its regeneration, this bioactive glasses have a particular interest and are in a continuous research and improvement. The chapter presents the history of bioactive glasses, classification, include a summary of common fabrication methods, applications, surface coatings, applications and future trends in relation to human bone. This review highlight new trends and areas of future research for bioactive glasses.

Part of the book: Current Concepts in Dental Implantology

By Petrica Vizureanu, Madalina-Simona Baltatu, Andrei-Victor Sandu, Dragos-Cristian Achitei, Dumitru-Doru Burduhos-Nergis and Manuela-Cristina Perju

The solar furnace works by using the electric energy produced by a photovoltaic system, which converts solar energy, solar radiation, into electric energy. The performances of the solar furnace used in various applications from industry are influenced by various factors. One of these factors imposes the acquisitions of certain large densities of the radiant power, and it requires a geometric form of the concentrator. The research is based on the behavior of some metallic alloys at elevated temperatures, for purifying some materials and for the achievement of some chemical synthesis. An important technological condition is a temperature which is achieved by concentrating solar radiation. This temperature is necessary to produce metallic material in the crucible, without other complementary energy for the thermal process. Steel or aluminum production requires very high quantities of thermal energy. Usually, this energy is given by electric power, natural gases, or conventional fuels. The solar furnace uses the energy given by the sun. For the manufacturing of the electrothermal furnaces, a series of specific materials are used, which are necessary for the obtaining of the furnace chamber, for the heating elements, as well as for the measurement systems of the temperature.

Part of the book: Latest Research on Energy Recovery