On corrosion properties of ceramic materials for pump friction pairs in lead – bismuth environment

2019 ◽  
pp. 116-122
Author(s):  
V. V. Stepanov ◽  
A. D. Kashtanov ◽  
S. U. Shchutsky ◽  
A. N. Agrinsky ◽  
N. I. Simonov
Keyword(s):  
Composite Materials ◽  
Heat Resistance ◽  
Experimental Research ◽  
Ceramic Materials ◽  
Operating Conditions ◽  
Metallic Materials ◽  
Corrosion Properties ◽  
Liquid Coolant ◽  
Radial Bearing ◽  
Axial Pump

We consider the results of studies on the choice of material of the lower radial bearing of the pump, designed to circulate the coolant lead – bismuth. The circulation of the liquid coolant is provided by a vertical axial pump having a “long” shaft. In this design it is necessary to provide for the lower bearing the lubrication carried out with lead – bismuth coolant. Having analyzed the operating conditions of the axial pump, we decided to carry out the lower bearing in accordance with the scheme of a hydrodynamic sliding bearing. The materials of friction pairs in such a bearing must withstand the stresses arising from the operation of the pump, as well as the aggressive conditions of the coolant. Non-metallic materials – ceramics and carbon-based composite materials – were selected basing on the study of literature data for experimental research on the corrosion and heat resistance in the lead-bismuth environment. 

Effects of the alumina reinforcement ratio on the corrosion properties of iron based composite materials

2020 ◽  
Vol 62 (11) ◽  
pp. 1094-1098
Author(s):  
Kubilay Karacif
Keyword(s):  
Composite Materials ◽  
Electrochemical Corrosion ◽  
High Hardness ◽  
Operating Conditions ◽  
Reinforcement Ratio ◽  
Working Environment ◽  
Corrosion Properties ◽  
Reinforced Composite ◽  
Iron Based ◽  
Composite Samples

Abstract Iron based composite materials reinforced with various ceramic particles are used in operating conditions requiring features such as high hardness, strength and wear resistance. The composite materials may be subject to corrosion depending on the working environment. In this study, the corrosion properties of iron based composite materials produced by powder metallurgy, containing carbon and different amounts of alumina reinforcement were investigated. In the materials production, 0.5 wt.-% carbon and 1, 3 and 5 wt.-% alumina powders were added to the iron powders as reinforcement. Followed by mixing, one-way cold pressing and sintering, respectively, both iron based carbon and alumina reinforced composite samples were obtained. The electrochemical corrosion properties of iron based composite materials containing various amounts of alumina reinforcement were investigated in a 3.5 wt.-% NaCl environment and the effects of the reinforcing material ratio on the corrosion behavior of the composite material were determined. It was determined that with an increase in the alumina reinforcement ratio, the corrosion rate of the material increases and the corrosion resistance decreases.

On the Properties of Anisotropic Piezoelectric and Fiber Reinforced Composite Materials

2006 ◽  
Author(s):  
Mohamed Gaith ◽  
Cevdet Akgoz
Keyword(s):  
Composite Materials ◽  
Elastic Fiber ◽  
Physical Property ◽  
Ceramic Materials ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Semiconductor Compounds ◽  
Degree Of Anisotropy ◽  
Tensor Basis

A new procedure based on constructing orthonormal tensor basis using the form-invariant expressions which can easily be extended to any tensor of rank n. A new decomposition, which is not in literature, of the stress tensor is presented. An innovational general form and more explicit physical property of the symmetric fourth rank elastic tensors is presented. The new method allows to measure the stiffness and piezoelectricity in the elastic fiber reinforced composite and piezoelectric ceramic materials, respecively, using a proposed norm concept on the crystal scale. This method will allow to investigate the effects of fiber orientaion, number of plies, material properties of matrix and fibers, and degree of anisotropy on the stiffness of the structure. The results are compared with those available in the literature for semiconductor compounds, piezoelectric ceramics and fiber reinforced composite materials.

scholarly journals Heat exchange between non-insulated barn and the ground in experimental research

2013 ◽  
Vol 12 (3) ◽  
pp. 035-038
Author(s):  
Wacław Bieda ◽  
Jan Radoń ◽  
Grzegorz Nawalany
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Experimental Research ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Final Conclusion

The paper presents the results of two-year studies conducted in real operating conditions of a non-insulated and unheated barn for 120 cows. As a result, it was possible to determine temperature fields in the ground beneath the floor and around the building, as well as to define heat flux directions. It was concluded that there is no analogy between temperature fields and heat flux directions with the heated buildings. In colder periods of the year, the heat accumulated in the ground is emitted to the inside of the building; in the summer, the ground absorbs the excess of heat from the building. The final conclusion was that the foundations should be insulated vertically.

scholarly journals The flexural strength of anisotropic composite plates with free edges

2021 ◽  
Vol 21 (1) ◽  
pp. 26-34
Author(s):  
Ashot G. Akopyan ◽  
Keyword(s):  
Composite Materials ◽  
Stress State ◽  
Classical Theory ◽  
Solid Mechanics ◽  
Composite Plates ◽  
Operating Conditions ◽  
Plate Bending ◽  
Structural Elements ◽  
Engineering Structures ◽  
Anisotropic Composite

Modern technology shows increased demands on the strength properties of machines, their parts, as well as various structures, reducing their weight, volume and size, which leads to the need to use anisotropic composite materials. Finding criteria to determine the ultimate strength characteristics of structural elements, engineering structures is one of the urgent problems of solid mechanics. Strength problems in structures are often reduced to finding out the nature of the local stress state at the vertices of the joints of the constituent parts. The solution of this urgent problem for composite anisotropic plates can be found in this article, where the author continues the research in this area, extending them to the bending of anisotropic composite plates. The aim of the work is to study the limit stress state of anisotropic composite plates in the framework of the classical theory of plate bending. The outer edges of the plate are considered to be free. Using the classical theory of anisotropic plate bending in the space of physical and geometric parameters, the hypersurface equations determining the low-stress zones for the edge of the contact surface of a composite cylindrical orthotropic plate are obtained. Modern technological processes of welding, surfacing, soldering and bonding allow to produce structural elements of monolithic interconnected dissimilar anisotropic materials. The combination of different materials with qualities corresponding to certain operating conditions opens up great opportunities to improve the technical and economic characteristics of machines, equipment and structures. It can contribute to a significant increase in their reliability, durability, reduce the cost of production and operation. On this basis, the solution proposed in this work can be useful to increase the strength of composite materials.

scholarly journals Carbonitration of a Tool for Pressing Stainless Steel Pipes

2020 ◽  
Vol 7 (2) ◽  
pp. C17-C21
Author(s):  
I. V. Ivanov ◽  
M. V. Mohylenets ◽  
K. A. Dumenko ◽  
L. Kryvchyk ◽  
T. S. Khokhlova ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Heat Resistance ◽  
Alkali Metals ◽  
Matrix Ring ◽  
High Hardness ◽  
Operating Conditions ◽  
Matrix Rings ◽  
Conventional Heat Treatment ◽  
The Stability

To upgrade the operational stability of the tool at LLC “Karbaz”, Sumy, Ukraine, carbonation of tools and samples for research in melts of salts of cyanates and carbonates of alkali metals at 570–580 °C was carried out to obtain a layer thickness of 0.15–0.25 mm and a hardness of 1000–1150 НV. Tests of the tool in real operating conditions were carried out at the press station at LLC “VO Oscar”, Dnipro, Ukraine. The purpose of the test is to evaluate the feasibility of carbonitriding of thermo-strengthened matrix rings and needle-mandrels to improve their stability, hardness, heat resistance, and endurance. If the stability of matrix rings after conventional heat setting varies around 4–6 presses, the rings additionally subjected to chemical-thermal treatment (carbonitration) demonstrated the stability of 7–9 presses due to higher hardness, heat resistance, the formation of a special structure on the surface due to carbonitration in salt melts cyanates and carbonates. Nitrogen and carbon present in the carbonitrided layer slowed down the processes of transformation of solid solutions and coagulation of carbonitride phases. The high hardness of the carbonitrified layer is maintained up to temperatures above 650 °C. If the stability of the needle-mandrels after conventional heat treatment varies between 50–80 presses, the needles, additionally subjected to chemical-thermal treatment (carbonitration) showed the stability of 100–130 presses due to higher hardness, wear resistance, heat resistance, the formation of a special surface structure due to carbonitration in melts of salts of cyanates and carbonates. Keywords: needle-mandrel, matrix ring, pressing, heat treatment, carbonitration.

Influence of microstructural defects and hydrostatic pressure on water absorption in composite materials for tidal energy

2018 ◽  
Vol 52 (21) ◽  
pp. 2899-2917 ◽  
Author(s):  
DM Grogan ◽  
M Flanagan ◽  
M Walls ◽  
SB Leen ◽  
A Doyle ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Composite Materials ◽  
Hydrostatic Pressure ◽  
Water Absorption ◽  
Glass Fibre ◽  
Tidal Energy ◽  
Operating Conditions ◽  
X Ray ◽  
Energy Devices ◽  
X Ray Computed

The lifespan and economic viability of tidal energy devices are constrained, in part, by the complex degradation of the tidal turbine blade materials due to prolonged immersion in a hostile sub-sea environment. Seawater penetration is a significant degradation mechanism in composite materials. This work aims to investigate the influence of microstructure and hydrostatic pressure on water absorption in four polymer composites which are candidate materials for use in tidal energy devices. These materials are: a glass fibre powder epoxy, a carbon fibre powder epoxy, glass fibre Ampreg epoxy and a chopped fibre glass fibre Polyether Ether Ketone. X-ray computed tomography is used to characterise the voids, resin-rich areas and other manufacturing defects present in each material. These defects are known to significantly alter the rate of moisture diffusion, as well as the total uptake of water at saturation. The samples are then exposed to accelerated water aging and hydrostatic pressurisation in order to simulate a range of expected sub-sea operating conditions. The material micro-structure, the matrix material and pressurisation level are shown to strongly influence both the moisture absorption rate and total water uptake. Significant volumetric changes are also noted for all samples, both during and after aging. X-ray computed tomography scans of specimens also provide a unique insight into the role of voids in storing water once a material has reached saturation.

Design of Hydraulic Motor Spindle for High Speed Machining

2000 ◽  
Author(s):  
Emmanuel I. Agba ◽  
Majid Babai
Keyword(s):  
Composite Materials ◽  
Electric Motor ◽  
High Speed ◽  
Operating Conditions ◽  
High Speed Machining ◽  
Strong Indication ◽  
Hydraulic Motor ◽  
Cutting Power ◽  
Spindle System ◽  
Distinct Increase

Abstract This paper presents the design of a hydraulic motor driven spindle for the processing of metals and composite materials at high rotational speeds. Existing technologies applicable to spindles and spindle holders under severe operating conditions were reviewed. A conceptual design of the hydraulic spindle system was developed. A strong indication of distinct increase in spindle life and gains in cutting power at higher rotational speeds when compared to the conventional electric motor driven spindles underscored the need for the new spindle system.

Silicon carbide fibers and whiskers for ceramic matrix composites (review)

2021 ◽  
Vol 87 (8) ◽  
pp. 51-63
Author(s):  
A. M. Shestakov
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
High Temperature ◽  
Composite Materials ◽  
Ceramic Matrix Composites ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Silicon Compounds ◽  
Reinforcing Fillers ◽  
Operating Temperatures

An increase the operating temperature range of structural elements and aircraft assemblies is one of the main goals in developing advanced and new models of aerospace equipment to improve their technical characteristics. The most heat-loaded aircraft structures, such as a combustion chamber, high-pressure turbine segments, nozzle flaps with a controlled thrust vector, must have a long service life under conditions of high temperatures, an oxidizing environment, fuel combustion products, and variable mechanical and thermal loads. At the same time, modern Ti and Ni-based superalloys have reached the limits of their operating temperatures. The leading world aircraft manufacturers — General Electric (USA), Rolls-Royce High Temperature Composite Inc. (USA), Snecma Propulsion Solide (France) — actively conduct fundamental research in developing ceramic materials with high (1300 – 1600°C) and ultrahigh (2000 – 2500°C) operating temperatures. However, ceramic materials have a number of shortcomings attributed to the high brittleness and low crack resistance of monolithic ceramics. Moreover, manufacturing of complex configuration and large-sized ceramic parts faces serious difficulties. Nowadays, ceramic composite materials with a high-temperature matrix (e.g., based on ZrC-SiC) and reinforcing filler, an inorganic fiber, (e.g., silicon carbide) appeared most promising for operating temperatures above 1200°C and exhibited enhanced energy efficiency. Ceramic fibers based on silicon compounds possess excellent mechanical properties: the tensile strength more than 2 GPa, modulus of elasticity more than 200 GPa, and thermal resistance at a temperature above 800°C, thus making them an essential reinforcing component in metal and ceramic composites. This review is devoted to silicon carbide core fibers obtained by chemical vapor deposition of silicon carbide onto a tungsten or carbon core, which makes it possible to obtain fibers a 100 – 150 μm in diameter to be used in composites with a metal matrix. The coreless SiC-fibers with a diameter of 10 – 20 μm obtained by molding a polymer precursor from a melt and used mainly in ceramic composites are also considered. A comparative analysis of the phase composition, physical and mechanical properties and thermal-oxidative resistance of fibers obtained by different methods is presented. Whiskers (filamentary crystals) are also considered as reinforcing fillers for composite materials along with their properties and methods of production. The prospects of using different fibers and whiskers as reinforcing fillers for composites are discussed.

Application of processing fiber-plastic composite washing

2021 ◽  
Vol 2021 (23) ◽  
pp. 214-224
Author(s):  
Artur Onyshchenko ◽  
◽  
Mykola Garkusha ◽  
Оlena Deli ◽  
◽  
...  
Keyword(s):  
Composite Materials ◽  
Operating Conditions ◽  
Structural Elements ◽  
Washing Machine ◽  
Normative Documents ◽  
Plastic Composite ◽  
Fiber Plastic ◽  
Fiberglass Composite ◽  
Composite Bridge

Introduction. Innovative, new materials are increasingly used in transport construction, among which composite materials are becoming widespread.Small bridges and elements of large bridges, such as roadway slabs, pavements, railings, composite reinforcement, reinforcement elements, are made of composite materials.Recently, the use of polymer composite materials for the manufacture of lightly loaded structural elements of transport structures, such as lighting poles, drainage trays, railings.Much attention should be paid to the fiberglass composite railing, which has a number of advantages over traditional metal fencing. Unfortunately, at present there are no clearly defined in Ukraine regulations on fiberglass composite fencing, so this topic is relevant and necessary for the transport industry.Problem Statement. From the literature analysis it is established that the railings of highways and sidewalks are in difficult operating conditions, are constantly exposed to aggressive environments - water, chemicals, salts.Goal. Increasing the durability of the railing by using new materials.Results. The analysis of production of a fiberglass profile is carried out. On the basis of the conducted researches the general requirements to a protection of fiberglass composite washing machine are established. On the basis of the current normative documents the classification of a protection on a place of installation, type of filling of a skeleton, a method of fastening of risers is developed. The paper presents the main parameters and dimensions of the fence. Material requirements are set. Methods of control of a protection with establishment of a technique of test of a protection on resistance to action of horizontal and vertical loadings are developed. Recommendations on installation and installation of a protection of fiberglass composite washing machine are offered.Conclusions. The research results were used in the development of technical conditions for the protection of fiberglass composite washing machine.Keywords: road, composite, bridge, fencing, profile, fiberglass, artificial construction

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