Materials Science Forum Vol. 818

Abstract: The aim of the study was to validate non-destructive diagnostics of surface of tools and metal sheets after steel grit blasting. We used replicas produced by fy Struers, known under commercial name RepliSet-F5. The replicas were extracted from surfaces of thirty specimens with PVD coatings (CrN, TiCN) and from flat specimens after steel grit blasting. Qualitative and quantitative parameters characteristic of surface morphology were determined by means of an optical profilometer, and confocal microscope was used for surface contactless metrology measurements. We observed a qualitative coincidence of morphological images of original surfaces and replicas. The values of the quantitative parameter Sa (Arithmetic mean height according to ISO 25178) of surfaces and replicas extracted from them differed at the second decimal place. Replicas document well the surface morphology and allow one to obtain information about the state of surface in difficult-to-access sites of the tools or constructions.

Abstract: Additive manufacturing technologies decrease production time and costs in engineering industry but also in other industries. Parts produced with Fused Deposition Modeling (FDM) have typical low surface finish quality. This paper is aimed on research of surface finishing technologies applicable to improve the quality of FDM prototypes surface finish. Pretreated samples were blasted with sodium bicarbonate and glass beads. The values of R_a and R_z were measured on the samples and compared the impact of selected pre-treatment, blasting medium and blasting conditions on surface finish quality of FDM prototypes.

Abstract: The article deals with the issue of evaluation of thin coatings for coating of cutting tools in order to increase their lifetime at higher temperatures. The aim of the experimental work was to determine the quality of two types of coatings - AlTiNmulti and AlTiCrN. The coatings were applied to the material Böhler 190 Microclean using PLATIT PL1001 Compact device at temperature of 430°C and pressure of 0,020 mbar. To determine the quality of coatings tribological test Pin-on-Disc was used, the counterpart was made of tungsten carbide (WC). Outputs of measurements were evaluated in Sensomp, which evaluates the results obtained from measurements using microscope PLu Noex. The results of the tests show that the AlTiNmulti coating is most suitable for use in environments with higher temperatures.

Abstract: The objective of this paper is the surface modification of silica pigments layer of polyaniline (PANI), poly (p-phenylendiamine) (PPDA) and chemical layer of zinc ferrite ZnFe₂O₄. This layer promote adhesively-barrier properties of silica particles without surface-treated. This pigment was specified using physico-chemical parameters (oil absorption, critical pigment volume concentration, density, pH extract and the specific electrical conductivity of pigment extracts). An epoxy ester resin was used as binder for the organic coatings investigated. Organic coatings were prepared in the following volume concentration PVC = 10 %. Organic coatings prepared were subjected to measurement of physical-mechanical properties by the following tests: relative surface hardness, adhesion test, bend test, impact test. Organic coatings were subjected to the following corrosion tests: in an atmosphere of SO₂ with water condensation. The results of mechanical and anti-corrosion tests provide evidence that was met premise increase adhesively-barrier properties of newly developed coating films.

Abstract: These days are in the automotive industry going to be still more and more used new types of protective coatings on the Zn-Mg basis. The advantage of these coatings is their excellent protection against corrosion of basic material. On the other hand disadvantage is mainly their low formability which takes effect at own stamping process. Such paper deals with the research influence of the deformation on the damage process of this coating. Size of deformation at different stress states was measured with the help of photogrammetry (system ARAMIS). Coating damage process at these stress states was monitored by means of optical and electron microscopy. Results of protective coating Zn-Mg damage process are presented in the form of strain distribution maps and images from optical and electron microscope.

Abstract: The paper is concerned with the performance properties of electro-spark deposited coatings, which were determined basing on microstructural and roughness analysis and application tests. The studies were conducted using of the tungsten carbide-ceramic electrodes produced by the powder metallurgy hot pressing route. The anti-wear coatings were electro-spark deposited over C45 carbon steel by means of an EIL-8A. These coatings are likely to be applied to increase the abrasive wear resistance of tools and machine parts.

Abstract: The contribution focuses to study of selected properties of thin coatings deposited on tool steel. Used samples were prepared by PVD method. Samples were evaluated using the scanning electron microscopy. Characteristics of surface morphology Ra, Rz Rt, RSm and RPc were established according to standard STN EN ISO 4287. The coatings TiN, TiCN, Supral and Exxtral Plus have been deposited on tool steel substrate having a thickness of 16 mm. The morphology characteristics were compared to the surface morphology of the reference material tool steel X155CrVMo12.1.

Abstract: The conventional and innovative surface technologies are applied to sheet metal stamping dies in order to produce a composite material with properties unattainable in either the base or surface material. To select proper materials for forming dies the systematic evaluation of dies materials, their heat treatment and coatings are required. This paper deals with evaluation of plasma sprayed coatings Cr₂O₃, Al₂O₃ and WC12Co by pressure plate-ring test (tester T 05) and deep drawing process. Friction coefficients and seizure of these coatings were studied under dry and wet friction conditions. For different types of die rings (with and without ceramic coatings) the punching forces were measured during deep-drawing process. The results show that the main advantage of application of plasma sprayed coatings on the die contact surfaces under wet friction conditions compare to dies made of the tool steel may be the increase of seizure resistance of stamped part surface. The more significant difference in the friction coefficient values was not observed.

Abstract: Thermally sprayed coatings, together with the deposition, belong among the most important technology both in the section of renovation and creation of functional surfaces. With the help of this technology it is possible to considerably improve the working life of the individual functional parts or to improve the range of their service parameters. Thermally sprayed coatings offer great variability both in light of backup materials (steels, non-ferrous metals, plastics), and in light of functional surfaces (metal powders, carbidic mixtures or ceramics). This paper describes individual types of powders with a view to properties and application possibilities of powders on the basis of W carbides with utilization of HVOF technology including a description of such method. Moreover the paper describes destructive and non-destructive tests for thermally created coatings. The experimental part is focused on the influence of pressure in the HVOF nozzle combustion chamber on the porosity and hardness of thermally sprayed coating for W carbide powders with different percentages of Co.

Abstract: Article deals with the assessment of the properties of ceramic coatings created by thermal spraying technology. Surfaces before coatings deposition were prepared by technology of pneumatic blasting. ZrSiO₄ coating was applied by gas plasma spraying method with NiAl intermediate layer. Mullite coating was applied by water plasma spraying without the intermediate layer and also with NiCr intermediate layer. The quality of the coatings was evaluated by three criteria: adherence of the coatings, REM analysis and EDX analysis. In terms of adhesion of the coatings was found out, that the best properties showed Mullite coating deposited without intermediate layer.