Papers by Keyword: Wear Resistance

Abstract: Plasma immersion ion implantation (PIII) method is often used to cleaning and enhancing mechanical properties of the surface of materials. In this work, the AISI 304 was treated in a PIII system to improve tribological and wear resistance properties. The new HV pulser was prepared to reach high average power (10 kW) using solid-state technology and a pulse transformer rather than using a conventional one based on hard-tube tetrodes with HV storage capacitors. For preliminary tests, low-density nitrogen plasma and pulses of 10 kV, 30μs width, and 1 kHz were used. A larger vacuum chamber used (600 liters) is very important for treating large area components and for batch processing. This is necessary in industrial applications and in cases that require high quality processing as in spatial or medical components. Stainless steel support was used to hold the samples in our case. XRD, SEM, and pin-on-disk surface diagnostics were used for investigation and characterization of the treated surfaces.

Abstract: This article deals with studying the relationships among the chemical composition, microstructure and properties (hardness, micro-hardness, wear resistance) of powder additives based on NiCrBSi after their deposition. Tested materials reached a relatively wide range of hardness after deposition, which corresponds to their chemical composition and microstructure. The abrasive wear resistance of materials was tested on an emery cloth. The results indicate that both the hardness and abrasive wear resistance of tested materials depend especially on the content of carbon and chromium. Microstructural analysis indicates that the structure of tested materials is formed by the γ-Ni solid solution and intermediate phases based on boron, silicon and carbon. Those mostly form eutectics (three types), or are excluded by precipitation. There was also found a significant effect of chromium, but especially carbon content on the ratio between the solid solution and eutectics in the microstructure of tested materials. These different ratios of solid solution and eutectics were markedly reflected in micro-hardness behaviours in deposited layers. Micro-hardness values confirmed also the presence of carbidic particles in the layers with carbon content higher than 0.7 wt%.

Abstract: Nanostructure WC composite coatings were prepared on surface of Q235 steel by argon arc cladding injection using microstructure WC feeding which were prepared by nanostructure WC powder. The microstructure of the coating were analyzed by scanning electron microscopy (SEM). Phase of the coating were analyzed by energy dispersive spectrometer and X-Ray diffract meter, moreover, microhardness and wear resistance were texted by Microhardness tester (HVST-1000) and friction wear testing machine (MMS-2A). The results show that the combination of coating and substrate is metallurgical bonding. and no Pores and cracks were founded in bonding area. aggregated nanostructure WC particles and nanostructure WC particles uniformly distributed in the coating. The maximum hardness of the coating is 1461 HV. Compared with the Q235 steel, the wear resistance of the coating increased about 15 times.

Abstract: Epoxy resin presents 3D cross-linking network structure characteristics after curing, resulting in a lower wear resistance of epoxy resin, which limits its extensive applications. In this paper, the effects of adding carboxyl functionalized carbon nanotubes on the tensile strength and wear resistance of carbon nanotube/epoxy composites were studied. The results showed that the tensile strength and wear resistance of the composites were effectively improved through carboxyl functionalization of carbon nanotubes.

Abstract: The article considers new technological principles of designing of vacuum-plasma coatings for ceramics on the basis of Al₂0₃–TiC and Si₃N₄ and the requirements for the following coatings: (Zr, Hf, Cr) N; (Ti, Cr) N; ZrN. Each of these coatings has specific features which can significantly improve working capacity of ceramics in various operation conditions. Technological process and the equipment for deposition of coating on ceramic samples and cutting plates are developed. Undertaken studies of the coatings deposited according to the developed technological principles, show ability to increase considerably beam strength of the samples from oxide-carbide and nitride ceramics. The article shows the possibility to replace grinding operation of details of bearings from tempered steels like ShH15SG type (62 ... 65HRC) to turning by the cutting tools equipped with plates from Al₂0₃-TiC ceramics with a coating (Zr, Hf, Cr)N.

Abstract: The proposed paper deals about the heat treatment of two types of chromium tool steels that are assigned to work in specific conditions of abrasion wear. The materials are heat treated to achieve high hardness for higher abrasion wear resistance. An additional increase of the materials abrasion wear resistance can be achieved by applying nitridation with diffusion annealing of the material surface. The paper deals about the influence of the material purity, his chemical composition on the process of diffusion, the quality of the nitrided layer of a vacuum smelted steel Bӧhler W400 VMR and a chromium steel X210Cr12.

Abstract: An investigation of coatings obtained by cladding of boron carbide on a low-alloyed steel substrate by an electron beam injected into the air atmosphere was carried out. It was shown that hardened layers had a heterogeneous structure formed during rapid cooling. It was established that a volume fraction of iron borides in the surface layer had a considerable impact on mechanical properties of the material studied.

Abstract: The nitriding process is well known as a method to improve wear, strength and corrosion characteristics of materials surface. The Institute of Materials Science of Leibniz Universität Hannover is on a stage of development of a new nitriding process under atmospheric conditions. The main purpose of the research work is formation of a nitrided layer on the locally loaded areas of a tool (e.g. forging die) under atmospheric conditions to increase wear resistance and durability of operating tools. Nitride layers were generated on the tool steel HS6-5-2C using the transmitted plasma arc. After atmospheric plasma nitriding the samples were investigated using optical microscopy, transmission electron microscopy (TEM), X-Ray diffraction (XRD) and microhardness testing techniques. It has been revealed that the modified zone thickness after atmospheric plasma nitriding reaches 200 μm. TEM and XRD analysis have shown that new phases corresponding to iron nitrides were formed in the surface zone. Microhardness of the surface layer is increased by 10% and friction coefficient has been reduced by approximately 50% in comparison with base material.

Abstract: This paper mainly introduces the new CrWMoV high-alloy wear resistant cast iron prepared by the composition design, the composition proportion and the melting and pouring, and analyses its microstructure and wear resistance. Microstructures and phases of the new CrWMoV high-alloy wear resistant cast iron were analyzed by scanning electron microscopy, energy dispersive spectrometer and X-ray diffract meter. Furthermore, the Rockwell hardness, impact toughness and wear resistance of the material were also studied. The result show that the composition of the new CrWMoV high-alloy wear resistant cast iron is mainly (V, W) C particles which is synthesized in-situ and evenly distributed in the composite, as well as a small amount of (Cr, Fe) ₇C₃ phase and Fe-Cr phase. The average Rockwell hardness of the composite is about 64.5 HRC, the average impact toughness is 9.85 J/cm², and the relative wear ability of the composite is about 2 times higher than the Cr15Mo2Cu which shows good wear resistance.

Abstract: The uneven friction of brake disk leads to the brake failure, which frequently results in serious traffic accidents. Based on the excellent wear-resisting properties of locust’s non-smooth surface structure, bionic brake disc with special surface micro-structure was designed. Utilizing ANSYS Workbench, the braking time and the stress distribution of both the bionic model and the smooth model during the whole process of brake under different initial velocity were analyzed. Compared to the smooth model, results showed that the braking time and contact stress decrease in a certain extent, indicating brake disc with special surface micro-structure exhibits relatively excellent braking performance and wear resistance. The results provided theories for exploring an optimization the method used to design brake discs with excellent braking performance and wear resistance.