Bogdan Antoszewski

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.

Laser surface texturing: chosen problems

In modern machines for realization of goals like lubrication intesyfication, heat flow intensyfiacation, microflow simulation; more and more often surface texturing is used. It became possible due to develepment of technologies that use sources of concentrated energy stream like microlasers. The paper shows results of experimental investigation on seal rings made of silicon carbide. Experiments were conducted using seal rings without surface modifications and a seal rings with a geometrical surface textures made with Nd:Yag laser.

Laser Texturing of Sliding Surfaces of Bearings and Pump Seals

Surface texturing is more and more frequently used in modern machines to attain such aims as lubrication enhancement, heat flow intensification and micro-flow stimulation. The development of technologies using concentrated energy flux, e.g. laser technology, has contributed to it. Pumps contain a lot of elements where textured surfaces can be used. The article concentrates on the selection of operating parameters of a picoseconds laser used to produce texturing in elements made of steel, bronze and silicon carbide.

Influence of Laser Surface Texturing on Scuffing Resistance of Sliding Pairs

This paper presents the results of experimental research on the impact assessment texture on scuffing resistance. The results showed that the texturing increases the resistance to scuffing. Above it has been shown that texture having a smaller surface energy and having a larger volume are more resistant to scuffing.

Tribological Properties of Coatings for Sheet Metal Stamping Dies

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.

The laser welding of iridium-platinum tips to spark plug electrodes

The paper presents selected results of model and technological experiments of welding iridium-platinum tips to spark plug electrodes. Variants of welding technology included different ways of preparing materials and the use of different Nd: YAG lasers (Rofin BLS 720 and Rofin Integral). The results of technological tests were verified by the metallographic evaluation of joints. Performance tests when powered by biogas were conducted for selected variants of welding.

Laser surface texturing of titanium alloys for biomedical applications

The article presents the methodology and results of laser surface texturing of the Ti6Al7Nb alloy. Laser treatment was carried out by means of a laser TruMicro 5325c Trumpf with a wavelength of 343 nm and a pulse duration of 6.2 ps. The impact of pulse frequency, scanning speed of a laser beam and laser power on the shape and dimensions of texture was studied. By selecting a suitable shape, size and density of laser texture for the surface of titanium alloys applied in knee replacement it is possible to reduce the coefficient of friction and wear of polyethylene to increase the osseointegration and adhesion of the coatings.

A study of laser-beam welding conducted at the Centre for Laser Technologies of Metals

The study reported here is part of a larger research project on laser-beam welding conducted at the Centre for Laser Technologies of Metals. The primary objectives were to compare laser-beam welding with a conventional process when used for longitudinal seams in street lamp posts, to select the process parameters for girth welds in cylindrical high-strength steel machine elements, and to assess whether laser-beam welding can be used for magnesium alloys. The paper includes recommendations for the selection of welding parameters.