Norbert Radek

Advanced Statistical Refinement of Surface Layer’s Discretization in the Case of Electro-Spark Deposited Carbide-Ceramic Coatings Modified by a Laser Beam

Carbide coatings have numerous industrial applications due to their high abrasion, sliding and erosion resistance. The paper presents results of an advanced statistical analysis – involving auxiliary simulation methods like smooth bootstrapping and imputing of missing data – executed on surface layer profile of modified carbide-ceramic coatings. Source data were gathered in the previous research by Radek and Bartkowiak focused on microstructure analysis (SEM Joel JSM-5400), microhardness (Vickers method), roughness (FORM TALYSURF-120L) and adhesion (CSEM REVETEST)) tests. Anti-wear coating were first deposited on carbon steel C45 from WC-Co-Al2O3 electrodes in the process of the electro-spark alloying (ESA) by the EIL-8a apparatus. In the next step the coating were laser melted using impulse mode of Nd:YAG laser (BLS 720 model). Due to significant irregularity of collected data, the special methods of smoothing and imputing were involved based on Monte-Carlo methods. The collected data set was several times randomly divided into analytical and verification sub-sets and mentioned methods were applied. The results were used to calculate descriptive statistics like average values, variances, confidence intervals and smoothed histograms of probability distributions. The validity of the proposed approach was positively verified and it significantly improved quality of the results. The smoothing and imputing of data allow to avoid numerical artifacts that may arise during the classical statistical calculations on irregular data.

The Average Friction Coefficient of Laser Textured Surfaces of Silicon Carbide Identified by RSM Methodology

The electrospark deposition (ESD) is a well-known cheap method utilizing concentrated energy flux to transfer a material of an electrode onto the surface of the machined material for enhancing properties of its surface layer. Typically, a hard material of an electrode may be deposited onto the surface of materials with lower hardness to make such an object more robust for wearing. Coatings produced by ESD may be applied to protect new elements or to recover the properties of worn elements. Unfortunately, ESD process produces a surface with high roughness. The laser beam machining (LBM) has been involved to lower roughness of the coating made by ESD. The elements coated by ESD have been tested to determine tribological properties and they were compared before and after LBM. To achieve high reliability of the results, the test has been conducted in accordance with design of experiments (DoE) methodology and the results which were obtained have been processed by a statistical analysis. The description of such an experiment performed for a silicon carbide SiC coating, the obtained results and the conclusions are included in this paper.

Electrospark Alloying of Carbon Steel with WC-Co-Al2O3: Deposition Technique and Coating Properties

The paper is concerned with the performance properties of electrospark deposited coatings. The properties were assessed by analyzing the coating microstructure, X-ray diffraction, microhardness, roughness and bonding strength.The studies were conducted using WC-Co-Al2O3 electrodes produced by sintering nanostructural powders. 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.

The Influence of Electrospark and Laser Treatment upon Corrosive Resistance of Carbon Steel

The influence on corrosion resistance of C45 carbon steel in chloride environment covered by coats of tungsten carbide and copper were examined. The coats were put on the surface of steel by electrospark method. The potentiodynamic polarization technique for corrosive investigations was applied. The topography of surface by scanning electron microscope (SEM) was observed. The most corrosion resistance was exhibited for steel covered by mixture of the 25% WC and 75% Cu nanopowders. The top layer of coating is not homogeneous and consists of copper, WC2, tungsten carbide and iron. The laser treatment modifies of the electrospark layer and influences on the correct it usable properties.

The Impact of Detection Methods on the Results of Quantitative Analysis of the Surface Layer WC-CoAl2O3

In the article authors presented digital measurement problem of the object on the 3D images of the microstructures. As a research material were used the micro tomography image of the probe C45 steel with WC-Co-Al2O3 surface layer. Due to relatively low contrast between the surface layer and the root material, and lack of sharp edges, some of the methods for automatic threshold indication may give biased results. Following the initial selection of the many methods of automatic binarization two of them and interactive method was selected to carry out comparative studies. The analysis included assessment of the layer thickness, number of detected objects and total volume of all detected objects.

Kinect application as virtual patient assistant on the example of the shoulder pain exercises

In the paper authors reports the first results of the working out application that would assistance and controls the patients during the rehabilitation exercise at home, what would effects in faster and more effective rehabilitation results. Proposed by authors conception of the application is programmed on the Kinect SDK environment and applies this simple and popular entertainment device to support rehabilitation process what ensure low costs of the implementation.

Application the 3D Image Analysis Techniques for Assessment the Quality of Material Surface Layer before and after Laser Treatment

In the paper authors presented the application of specific method of assessment chosen properties of coating layer, that give additional information strictly connected with its tribology properties. Nanotomography techniques and 3D image processing gives quantitative and qualitative information about the testing sample, with no negative effects on the exanimating layer. Two samples, one with and one without the laser treatment were tested, measured and obtained results presented and discussed. Those preliminary research shown that proposed method can be recommended to application as a supplementary test of the properties coating layers and for verification of technological process parameters on the stage of working out the production process.

Operational Properties of Anti-graffiti Coating Systems for Rolling Stock

The article presents the comparative tests results of selected properties of anti-graffiti paint system for rolling stock industry. The measurements included an adhesion test, free surface energy, surface geometric structure, corrosion resistance and flame resistance test. The system consists of high solid corrosion protection primer, putty, filler, basecoat and anti-graffiti clearcoat.

Production and properties of electro-spark deposited coatings modified via LBM

The paper is concerned with determining the influence of laser treatment process on the properties of electro spark coatings. The properties were assessed after a laser treatment by analysing microstructure and X-ray diffraction and measuring surface geometric structure and microhardness. The studies were conducted using WC-Cu electrodes produced by powder metallurgy of nanostructural powders. The coatings were deposited by means of the EIL-8A model and they were laser-treated with the Nd:YAG, BLS 720 model.

Experimental Analysis of Tribological Properties of Heat Treated Graphitic Cast Irons

The results of research investigations of tribological properties of heat-treated cast iron with globular graphite are presented. The samples of investigated materials, including the reference material steel C45 were heat treated to the same hardness value. Tests were carried out on the experimental device with a linear reciprocal movement with variable speed using the Ball on Plate method. The device simulates real changed conditions in different environments of the tested contact pairs, such as sliding bearing, hinges, brackets and the like. The results of measured tribological properties of materials show that for practical applications and for specific environments and dynamic conditions the replacement of the original material C45 by isothermally tempered cast iron may be realistic.