Purpose: The paper presents the results of investigations of Ni-B/Si3N4 composite layers produced on steel substrate by electroless method. Design/methodology/approach: Amorphous silicon nitride powder (Si3N4) with nanometric particle sizes was used as a dispersion phase for the production of composite layers. Ni-B/Si3N4 composite layers were produced in baths of varying Si3N4 powder content. For comparative purposes, the study also includes results related to a Ni-B layer. The Si3N4 powder and the structure of the produced layers were characterized. The topography and morphology of the surface of the produced layers are presented. The adhesion of the layers to the substrate material was determined. Microhardness and tribological properties of test materials were determined. Findings: The results of the studies show that Ni-B/Si3N4 composite layers and Ni-B composite layers are characterized by compact structures and good adhesion to the substrate material. The incorporation of Si3N4 particles into the Ni-B layers increases the degree of surface development of the layers. The Ni-B/Si3N4 composite layer material exhibits less microhardness and less abrasive wear compared to Ni-B layers. However, the extent of wear damage of the Ni-B/Si3N4 is relatively small comparing to Ni-B layers.

W artykule przedstawiono wyniki badań powłok kompozytowych Zn/PTFE wytwarzanych metodą redukcji elektrochemicznej w kąpieli siarczanowo-boranowej o różnej zawartości fazy dyspersyjnej PTFE. Scharakteryzowano budowę wytworzonych powłok oraz oceniono wpływ wbudowania cząstek PTFE na mikrotwardość wytworzonych powłok kompozytowych Zn/PTFE. Wytworzone powłoki charakteryzują się zwartą, jednolitą budową i dobrym połączeniem ze stalowym podłożem. Wbudowanie cząstek PTFE w cynkową osnowę ma wpływ na strukturę i morfologię wytworzonych powłok kompozytowych, powoduje zwiększenie stopnia rozwinięcia powierzchni powłok oraz zwiększenie twardości materiału powłoki w porównaniu z powłoką cynkową.

The results of research on preparations of alloy Ni-B/B composite coatings produced by chemical reduction method on a carbon steel substrate are collected in this paper. The alloy Ni-B coatings were also investigated for comparative purposes. The produced coatings were subjected to a heat treatment process. The boron powder with the particles size below 1 μm was used as the dispersion phase. The structure of the coatings was examined by X-ray diffraction method. Boron powder particles as well as surface morphology and topography were characterized by scanning electron microscopy. The roughness test, microhardness and corrosion resistance by potentiodynamic method and surface wettability tests were carried out. Analysis of the chemical composition by the EDS method showed that the boron powder particles were evenly embedded in the entire volume of the coating. Ni-B/B composite coatings are characterized by higher hardness than alloy Ni-B coatings. As a result of heat treatment, the Ni 3 B phase crystallized, which increased the hardness of the coating material. The incorporation of boron powder particles and heat treatment reduce the corrosion resistance of coatings. All produced coatings exhibited hydrophobic properties.

The paper presents the results of studies of hybrid composite layers Ni/Al 2 O 3 /C graphite produced by the electrodeposition method. Three variants of hybrid composite layers were prepared in electrolyte solutions with the same amounts of each dispersion phases which were equal to 0.25; 0.50 and 0.75 g/dm 3 . The structure of Ni/Al 2 O 3 /C graphite layers as well as the Al 2 O 3 and graphite powders, which were used as dispersion phases was investigated. The results of morphology and surface topography of produced layers are presented. The modulus of elasticity and microhardness of the material of produced layers were determined by DSI method. Tribological and corrosion resistance tests of produced layers were carried out. Realized studies have shown that the material of the produced layers is characterized by a nanocrystalline structure. Incorporation of dispersion phases into the nickiel matrix increases the degree of surface development of layers. Ni/Al 2 O 3 /C graphite layers are characterized by high hardness and abrasion resistance by friction, furthermore, they provide good corrosion protection for the substrate material.