Modern approaches to ensuring the necessary characteristics of surface of a material with the aim to improve economic and technological characteristics of the structures are considered in this paper. It is shown that aluminium alloys gain wide application in industry. Nevertheless, surface characteristics of materials are insufficiently good for their use in structures which operate under abrasive wearing and boundary friction.The use of the method of surface modification by a concentrated light-beam of energy is of prospect. Analysis of literature data indicates that in the course of laser-modification of surface of an aluminium alloy it is possible to form a material whose operational characteristics are higher than those of the material in its initial state. However, herewith it is important to quantitively estimate properties of the obtained composite layer on the surface of the article as well as to estimate the distinction between the layer and the main metal.The microstructure of laser-modified composite layers of aluminium alloys which had been formed by means of direct blow-in of SiC powder into the melted by laser radiation zone of surface has been investigated.Laser reinforcement of surfaces of aluminium alloys by SiC particles causes pronounced inhomogeneity of structure of surface layers of alloys. It has been shown that preliminary heating of specimens in the course of their laser-treatment increases the depth of the modified layer over the whole zone of treatment and improves the uniformity of distribution of reinforcing SiC particles; however, because of turbulence in the melt there is observed some non-uniformity of distribution of SiC particles in the modified layer.It is found that in the interaction of Al melt with SiC particles there forms plates of Al 4 C 3 carbide at the interface, these plates grow mainly co-axially to the orientations of SiC crystals in the direction to the melt. Besides, in the matrix there takes place partial dissolution of SiC with formation of needle-shaped Al 4 C 3 carbides.During the modification of surfaces of these alloys, in the case of increased concentration of silicium in the melt there is also observed inclusion of pure silicium. Besides, there is also possible the diffusion of aluminium into thin near-surface layer of silicium carbide, the layer separates from SiC crystal (phenomenon of ply separation) when the concentration of aluminium reaches a value of 3-5 %.
The aim of the study. By introducing strong oxidizers to the electrolyte form anode layers on the surface of aluminum with increased mechanical characteristics. To determine the effect of the duration of the formation of an anode layer to change its properties. Hard anodizing was performed at a temperature of –4...0C for 60 min. A 20% aqueous solution of H2SO4 was used as the base electrolyte. During anodizing, the current density was 5 A/dm2. To determine the effect of strong oxidants on the characteristics of the anode layers (oxide), 30 were added to the electrolyte; 50; 70 and 100 г/лof hydrogen peroxide (H2O2). In some cases, it was purged with an ozone-air mixture at a rate of 5 mgmin/l of ozone. It was found that the oxide layer (Al2O3H2O) during hard anodizing on aluminium alloys forms not only oxygen ions, which are formed by the decomposition of water, but also neutral oxygen atoms, which are formed by the decomposition of hydrogen peroxide and ozone. It was found that hydrogen peroxide, as well as blowing the electrolyte with an air-ozone mixture increase the thickness and microhardness of the anodized layer by 50% due to the reduction of the number of water molecules in alumina by half. Hydrogen peroxide and ozone apparently also reduce the thickness of the barrier layer of the coating, through which oxygen and aluminium ions penetrate and which, when combined, form an oxide layer. Conclusions. 1. It has been established that aluminum anodizing for 60 minutes. provides an increase in its properties. Changing the composition of the electrolyte contributes to the growth of microhardness in 1.2 ... 1.7 times. The resistance of abrasive wear increases with the content of different amounts of applications in the electrolyte and the maximum is at 30 g / l H2O2. Blowing the base electrolyte ozone provides an increase in the microhardness of the layer from 380 to 510 HV. The higher loss of mass for higher microhardness is caused by an increase in porosity of coatings. 2. It is determined that an increase in the anodization time in the baseline electrolyte to 120 and 180 minutes contributes to the growth of microhardness to 640 HV compared to an anodized layer for 60 minutes. Loss of mass in the study of abrasive wear is less than 3-4 times with longer anodation than at 60 minutes in the baseline electrolyte.
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