Elastomeric Materials for Mining Equipment Operating in the Far North

Operation of elastomeric materials in the extreme climatic conditions of the North is complex and expensive, since not always existing materials can provide the required level of low-temperature characteristics (down to - 60 °C). This leads to failure of machines and mechanisms, equipment downtime, additional costs for repair or replacement of elastomeric parts. This study investigates the features of elastomeric composites operation in cold climates and the results of full-scale tests with simultaneous exposure to naturally low temperatures and hydrocarbon environments in Yakutia (Siberia, Russia). It presents the main principles of creating elastomeric composites for sealing purposes with high frost resistance and examples of recent developments. To obtain elastomeric materials of high frost and oil resistance new rubbers of high frost resistance as Hydrin T6000 epichlorohydrin rubber (Tg = - 60 °C), and traditional rubbers (nitrile etc) were used. For elastomer modification we used carbon nanotubes, collagen hydrolysate and polymer mixtures. Different type of developed materials is a double-layer material based on ultra-high-molecular-weight polyethene (UHMWPE) and nitrile-butadiene rubber-based elastomeric composite. The effect of diphenylguanidine on the interaction of UHMWPE with elastomeric composite based on nitrile butadiene rubber and adhesion at the interface was investigated. The operating properties were studied by standard methods and the structure of the obtained materials was studied using electron microscopy.

Properties of multi-layer renders with fly ash and boiler slag admixtures for salt-laden masonry

Corrosion and mechanical behaviour Of Al2o3.Tio2 composites produced by spark plasma sintering

The article discusses the influence of complex additives on the strength and resistance of cement composites to environmental impacts. One of the additives - PFM-NLK (concrete modifier)- a factory fabricated mixture of a superplasticizer with the addition of air-retaining and water proofing substances. Another one is a complex additive containing a superplasticizer, sodium tetraborate and boric acid.Common denominator is the content of the superplasticizer. It allows reducing the W / C ratio of the mixture thereby increasing the density and strength of the composite, and, accordingly, its frost and corrosion resistance. PFM-NLK water-proofing and air-retaining substances additionally work toward the formation of a material structure with increased frost resistance. The components of the other additive, boric acid and sodium tetraborate, form a borate buffer system, which leads to the softening of the “chemical impact” and thus further increases the corrosion resistance. The research findings revealed the effectiveness of complex additives and substantiated the regularity that if each factor is separatelyfacilitative forproperty improvement, then, when they are combined, the effect is multiplied. The PFM-NLKcomponents, when combined, contribute to obtaining a material structure with high frost resistance. An additive containing a hyper-plasticizer, boric acid and sodium tetraborate leads to an increase in strength and acid resistance.

Cobalt-based alloys have been widely used in implant components, especially in orthopaedic implants. The biocompatibility of CoCrMo alloy is related closely to this material’s excellent corrosion resistance, imparted by a thin passive chromium oxide layer with some minor contributions from Co and Mo oxides. The oxide film on CoCrMo alloy inhibits the dissolution of metal ions but is not always stable in the human body. There is a general agreement that corrosion is a serious problem for medical metallic materials. For joint replacements, they are exposed to tribological contacts and load so their performance (long-term durability) relies on both their corrosion and wear resistance. Diamond like carbon (DLC), with its extreme smoothness, hardness, low coefficient of friction, and biocompatibility is an excellent candidate to serve as a tribology-enhancing and corrosion-protective functional coating.

The problem of resistance of winter wheat to low negative temperatures is one of the most important in the agriculture economy, the solution of which will contribute to the increase of yield and gross grain harvesting in the Russian Federation. Therefore, the creation of winter wheat varieties capable of resisting the effects of frost during winter is very relevant. The aim of the study is to identify high frost-resistant winter wheat varieties for use in the breeding process by direct and indirect methods of assessment, and to define the possibility of using free proline content to detect genotypes resistant to low negative temperatures. The paper presents the results of complex studies on frost resistance of winter soft wheat varieties by three scientific centers: Agricultural Scientific Center Donskoi, National Grain Center named after P.P. Lukyanenko and Federal Rostov Agrarian Scientific Center. Therein is shown the possibility of using an indirect method - defining free proline content as a method of assessing frost resistance of samples. After freezing plants grown in sowing boxes at four different temperatures, varieties were identified that significantly exceeded the Tarasovskaya 29 classifier in plant safety: Polina, Volnitsa, Volny Don, Ascetic, Don Bezostaya, and Don 107. Samples that were distinguished by the safety of plants in direct evaluation methods also showed a high content of free proline in laboratory and field experiments. Correlation analysis between the values of various methods for assessing frost resistance showed their close relationship. Varieties of winter soft wheat characterized by high frost resistance, on average, accumulate more of this amino acid in the leaves in laboratory and field experiments.

In seeking to produce lightweight aluminum block based engines, a variety of metallurgical and surface modification techniques for cylinder bores, pistons and piston rings are available. This paper discusses these various alternative methods while placing particular emphasis on electroplated nickel ceramic composite coatings (NCC). NCC Coating properties are characterized by high hardness, high corrosion resistance, high temperature wear and scuff resistance and low frictional coefficients. The application of NCC Coatings in 2-stroke motorcycle and diesel engines has resulted in benefits in the following areas: elimination of cast iron liners; reduced cylinder wall temperature, engine weight and increased power; lowering of oil consumption; improved fuel economy; reduction in emissions; improved scuff and wear resistance on cylinder bores, pistons and piston rings; friction reduction; combating of piston ring groove microwelding and pound out; thermal barrier protection on diesel piston domes; reduction in carbon deposition on piston domes; reduced noise from piston slap; and ability to operate in corrosive environments. The sum of the above stated benefits holds much potential for contributing towards greater flexibility in materials selection for the design of lightweight, fuel efficient vehicles based upon the use of aluminum engines. 13 refs., 13 figs.

A novel sintering method of Al2O3/SiCw ceramic composites with improved wear resistance: Oscillatory pressure‐assisted sinter forging

The tribological properties of chemical-vapor-deposited (CVD) diamond films vary with the environment, possessing a Jekyll-and-Hyde character. CVD diamond has low coefficient of friction and high wear resistance in air but high coefficient of friction and low wear resistance in vacuum. Improving the tribological functionality of materials (such as achieving low friction and good wear resistance) was an aim of this investigation. Three studies on the surface design, surface engineering, and tribology of CVD diamond have shown that its friction and wear are significantly reduced in ultrahigh vacuum. The main criteria for judging whether diamond films are an effective wear-resistant, self-lubricating material were coefficient of friction and wear rate, which must be less than 0.1 and on the order of 10(exp 6) cu mm/N(dot)m, respectively. In the first study the presence of a thin film (less than 1 micron thick) of amorphous, nondiamond carbon (hydrogenated carbon, also called diamondlike carbon or DLC) on CVD diamond greatly decreased the coefficient of friction and the wear rate. Therefore, a thin DLC film on CVD diamond can be an effective wear-resistant, lubricating coating in ultrahigh vacuum. In the second study the presence of an amorphous, nondiamond carbon surface layer formed on CVD diamond by ion implantation significantly reduced the coefficient of friction and the wear rate in ultrahigh vacuum. Therefore, such surface layers are acceptable for effective self-lubricating, wear-resistant applications of CVD diamond. In the third study CVD diamond in contact with cubic boron nitride exhibited low coefficient of friction in ultra high vacuum. Therefore, this materials combination can provide an effective self-lubricating, wear-resistant couple in ultrahigh vacuum.

Peristaltic pump units are used in medicine, for pumping blood and its components, and in mechanical engineering for working with aggressive media. The only element in this pump that comes into contact with the working medium is the hose. Such hose characteristics as chemical resistance and wear resistance directly affect the operating life of the entire pump. The purpose of this work is to increase the service life of the peristaltic pump unit by developing a hose with improved wear resistance (WRH). During the study, the following problems were solved: the process of obtaining 3 different polymer materials for the manufacture of WRHs was selected, the technology for manufacturing WRHs was selected, and the mechanical properties of the resulting structure were studied. As a result, it was determined that all selected materials and design were workable, however, a sample made of ethylene-propylene rubber (EPDM) and polypropylene (PP) with a mass percentage of 75/25 (75% EPDM and 25 % PP) material, has the greatest wear resistance in comparison with other samples, which makes it optimal for making a hose.

Aluminium components have gained significant importance in aerospace, naval, sports, and structural applications due to their lightweight, corrosion resistance, and high strength - to - weight ratio. However, pure Aluminium has limitations, such as high wear rate and low hardness, restricting its use in specialized applications. Carbon, known for its exceptional strength and hardness due to its tetra - valent bonding, exists in multiple allotropes, including Diamond and Graphite. Graphene, a single - layer allotrope of carbon derived from Graphite, exhibits outstanding mechanical properties, including high tensile strength, superior wear resistance, and a low coefficient of friction. Reinforcing Aluminium 6061 with Graphene enhances its properties, making it more suitable for advanced applications. This study focuses on fabricating Aluminium 6061 - Graphene metal matrix composites (MMC) using the stir casting technique, incorporating Graphene reinforcement in weight percentages of 0%, 0.5%, and 1%. The casted composites undergo heat treatment, and specimens are prepared following ASTM standards for wear testing. Wear behavior is analyzed under dry friction conditions using an EN - 32 steel rotating disc with a surface roughness of 0.394?m and hardness of 62 HRC. The experiment is conducted at a fixed track length of 2000 meters, a sliding velocity of 1.256 m/sec, and normal loads of 20N, 30N, and 40N. The results indicate that Graphene reinforcement significantly enhances the wear resistance of Aluminium 6061, reducing frictional force and improving the coefficient of friction. The mechanical properties of the composite vary based on the Graphene content and applied load, demonstrating an improvement over as - cast specimens. This study highlights the effectiveness of Graphene as a reinforcing material for Aluminium - based MMCs, offering improved wear resistance and mechanical performance for specialized applications. The findings contribute to the development of advanced materials for industries requiring high - strength, wear - resistant components.

In this study AISI H13 steel was treated with oxynitriding, CrN coating, and CrN coated with oxynitriding to investigate the molten loss for melting A380 aluminum alloy and wear resistance. The experimental results indicate that the minimum melting loss appeared in duplex surface treatments of CrN coated with oxynitriding after a 3h erosive test. Weight loss was only 0.8%; however the untreated specimen was 3.2% .I n addition, all specimens following the different surface treatments, showed a higher wear resistance after the wear test. The untreated specimen showed obvious traces of plough cracks. Conversely, other surface treated specimens experienced very shallow wear. This result shows that the wear resistance of AISI H13 can be effectively improved by performing various surface treatments. The lowest coefficient of friction also appeared in the duplex surface treatment of CrN coated with oxynitriding. The average value of frictional coefficient was 0.28. [doi:10.2320/matertrans.M2011360]

CHAPTER 17 - Polytetrafluoroethylene matrix nanocomposites for tribological applications

Titanium carbide is a refractory material [1] which combines ceramic properties such as high melting point (3067°C), high hardness (2800HV), thermal and chemical stability, wear and corrosion resistance, and certain metallic properties such as low friction coefficient, high electrical and thermal conductivity. Consequently, it can be used as protective coating against thermal, chemical, and mechanical wear. Typical applications include high performance cutting and forming tools, high corrosion resistance coatings for molten metal containers, thermal barrier in fusion reactors and chemical reactors and diffusion barrier in semiconductor technology.

PurposeThe increasing demand for advanced materials in structural applications requires components that can withstand diverse load conditions while offering a combination of mechanical properties to improve overall performance. Dissimilar material joints, such as those between IN625 and AISI316, offer promising potential due to their unique properties. However, achieving reliable and high-performing joints between dissimilar materials remains a challenge, particularly in maintaining strength, wear resistance and hardness under varying conditions. The purpose of this study is to improve the performance of friction stir welded dissimilar joints between IN625 and AISI316 alloys using nanoparticles.Design/methodology/approachThis study examines the mechanical properties of friction stir welded (FSW) dissimilar joints between IN625 and AISI316 alloys, with and without reinforcement by Al2O3 and TiO2 particles. The tensile strength, wear rate, coefficient of friction, microhardness and compressive strength of these joints were evaluated and compared to the base materials.FindingsResults showed that the FSW process significantly improved the mechanical properties, with the particle-reinforced joints outperforming the non-reinforced ones. In particular, the IN625-AISI316/Al2O3 joint exhibited the highest tensile strength (690 MPa), lowest wear rate (1.92 × 10³ mm³/m) and the lowest friction coefficient (0.32). Microhardness testing revealed that the weld nugget (WN) region displayed the highest hardness (227 HV) due to grain refinement. The compressive strength of the IN625-AISI316/Al2O3 joint reached 1,583 MPa, the highest among all samples tested. These findings demonstrate the potential of using particle-reinforced FSW dissimilar joints for applications requiring superior mechanical performance, durability and wear resistance.Originality/valueThis study explores the enhanced mechanical and wear properties of FSW dissimilar joints between IN625 and AISI316 alloys, with and without Al2O3 and TiO2 nanoparticle reinforcements. Reinforced joints, particularly IN625-AISI316/Al2O3, showed superior tensile strength, wear resistance, hardness and compressive strength compared to non-reinforced ones. Grain refinement in the WN region contributed to increased hardness. These findings suggest that nanoparticle-reinforced FSW dissimilar joints can significantly improve durability and mechanical performance, making them ideal for demanding structural applications.