More information
Description
The subject of the project concerns composite coatings with a Ni-B matrix and boron (B) or molybdenum sulphide (MoS2) as the dispersion phase. The coatings will be produced by chemical reduction method on a steel substrate from multi-component solutions. Boron will occur in two forms: an alloy component and nanoparticles incorporated into the matrix. It is planned to produce several variants of coatings differing in the content of the dispersion phase in the bath. The particles embedded in the matrix material will influence the structure and properties of the tested materials. Ultimately, it is planned to obtain materials with a hardness above 900 HK0.025. This hardness is achievable by the chromium coatings. However this kind of coatings has to be replaced with other materials due to the limitations expressed in EU Directives and REACH regulations. Other benefits of incorporating B or MoS2 particles will be an increase in wear resistance and an improvement in corrosion resistance compared to Ni-B coatings without embedded particles. The research plan assumes the production of Ni-B/B and Ni-B/MoS2 coatings with different parameters of the deposition process (bath composition and temperature, deposition time, mixing method, additives, etc.). Then, the produced materials will be characterized by scanning, light microscopy, X-ray diffraction, X-ray fluorescence spectroscopy, roughness parameters measurements, metallography, Knoop/Vickers hardness measurements, tribological tests, electrochemical corrosion tests. The coatings proposed will be manufactured on a laboratory scale and on a semi-technical scale galvanic line. The results of the project will be used for the scientific development of the Principal Investigator and the research team, as well as for the development of technology in order to apply the process and composite alloy coatings in the industry.
Summary of project results
The subject of the project concerns composite coatings with a Ni-B matrix and boron (B) or molybdenum sulphide (MoS2) as the dispersion phase. The coatings were produced by chemical reduction method on a steel substrate from multi-component solutions. The produced materials were characterized by scanning, light microscopy, X-ray diffraction, X-ray fluorescence spectroscopy, roughness parameters measurements, metallography, Knoop/Vickers hardness measurements, tribological tests, electrochemical corrosion tests. The results of the project for the development of technology in order to apply the process and composite alloy coatings in the industry.
Coatings were produced by chemical reduction method on steel substrate from multi-component solutions. Boron occurred in two forms: alloying component and nanoparticles incorporated in the matrix. Several variants of coatings were produced differing in the content of dispersion phase in the bath. Particles embedded in the matrix material influenced the structure and properties of tested materials. Materials with hardness above 900 HK0.025 were obtained. Such hardness is achieved by chromium coatings, which should be replaced by other materials due to restrictions expressed in EU directives and REACH regulations. Other benefits resulting from the inclusion of B or MoS2 particles include increased wear resistance and improved corrosion resistance compared to Ni-B coatings without embedded particles.
The most important results concern the influence of the concentration of the boron dispersion phase embedded in the Ni-B alloy coating material on the functional properties of the composite coatings. The results show that deposition of coatings from baths with a boron particle concentration of 1 g/dm3 gives the most favourable performance properties. The results obtained have a good economic utility since the set goals concerning the hardness properties of the layers have been met, the composition of the bath has been determined and can be controlled and investigations have already been performer on a semi-industrial scale which will facilitate its further use for industrial applications