The mechanisms of element redistribution in the surface layer of multicomponent alloys during their irradiation by high power pulsed ion beams

It is shown that redistribution of elements in the surface layer proceeds depending on a type of the stable diagram ("based" element-alloyed element) if treatment by high power pulsed ion beam takes place under the melting condition, when irradiation has been conducted at low values of ion current density (j<60 A cm'2). Here the impurity having a coefficient of distribution (ki) lesser 1 is supplanted by the solidified front to the surface but if ki>1 than the element is concentrated in the zone between matrix and solidified alloy. This mechanism and else a mechanism of intense evaporation of volatile components proceed during irradiation at higher values of j. At j>120-140 A cm'2 the chemical composition of the surface changes "from point to point” to a great extent due to crater formation

The mechanisms of element redistribution in the surface layer of multicomponent alloys during their irradiation by high power pulsed ion beams

It is shown that redistribution of elements in the surface layer proceeds depending on a type of the stable diagram ("based" element-alloyed element) if treatment by high power pulsed ion beam takes place under the melting condition, when irradiation has been conducted at low values of ion current density (j<60 A cm'2). Here the impurity having a coefficient of distribution (ki) lesser 1 is supplanted by the solidified front to the surface but if ki>1 than the element is concentrated in the zone between matrix and solidified alloy. This mechanism and else a mechanism of intense evaporation of volatile components proceed during irradiation at higher values of j. At j>120-140 A cm'2 the chemical composition of the surface changes "from point to point” to a great extent due to crater formation

Kinetics of evaporation from the surface of refractory nickel and titanium alloys with heat resistant coatings during their irradiation by high-power pulsed ion beams

The effect of the irradiating conditions by high-power pulsed ion beams (HPPIB) on the ablation rate was studied. The conditions of irradiation (ions of carbon and protons, ion energy E=300-600 keV, the ion current density in a pulse j=60-500 A cm" pulse duration т=50-100 ns) were realized in Temp and Vera accelerators. The study of the evaporation kinetics was carried out using targets manufactured from GS26NK nickel super-alloy with NiCrAlY coating and from VT9 and VT18U titanium alloys with ZrN and TiSiB coatings. It is shown that values of the ablation rate achieve 0.04 µm (TiSiB), 0.4 µm (NiCrAlY), and 1 µm (ZrN) during a pulse under the optimal conditions of HPPIB irradiation

Kinetics of evaporation from the surface of refractory nickel and titanium alloys with heat resistant coatings during their irradiation by high-power pulsed ion beams

The effect of the irradiating conditions by high-power pulsed ion beams (HPPIB) on the ablation rate was studied. The conditions of irradiation (ions of carbon and protons, ion energy E=300-600 keV, the ion current density in a pulse j=60-500 A cm" pulse duration т=50-100 ns) were realized in Temp and Vera accelerators. The study of the evaporation kinetics was carried out using targets manufactured from GS26NK nickel super-alloy with NiCrAlY coating and from VT9 and VT18U titanium alloys with ZrN and TiSiB coatings. It is shown that values of the ablation rate achieve 0.04 µm (TiSiB), 0.4 µm (NiCrAlY), and 1 µm (ZrN) during a pulse under the optimal conditions of HPPIB irradiation

Surface modification of refractory alloys with high-power pulsed ion-beam treatment and arc-pulsed ion implantation

High-power pulsed ion beam (HPPIB) treatment and arc-pulsed ion implantation (APII) were combined consecutively to be the improvement of service properties of high temperature refractory alloys. The influence of this combined processing on the physical and chemical state of refractory alloy surface layers was studied. It is shown that it is possible to combine the positive effects of each technology in order to obtain an ideal smooth surface (without craters, Ra =0.06-0.10 pm) and to increase the alloyed surface layer thickness due to irradiation-enhanced diffusion. Consequently, the positive effect of this combined treatment on the fatigue strength, salt corrosion resistance, and oxidation resistance is connected with the following processes: smoothing of a surface microrelief; high-speed-solidification; surface alloying; structure stabilization during a post-process vacuum annealing

Surface treatment of dental implants with high-power pulsed ion beams

The objective of the present research is development of НРРІВ technology for surface processing of compact components with a complex shape. The surface state of the dental implants from titanium alloys before and after irradiation and long time operation was investigated by Auger electron spectroscopy, scanning electron microscopy, X-ray structural analysis, optical metallography methods. It is shown that the homogeneous state in the surface layer of titanium alloys is formed due to the irradiation (carbon ions and protons, energy of ions is equal to 300 keV, density of ion energy in a pulse achieves 1-5 J/cm^). This state is characterized by a low amount of the impurities and a fine dispersional structure formed as a result of high speed crystallization. Thus, HPPIB irradiation of the dental implants leads to formation of developed microrelief and the decrease of impurities content on the surface. As a result, this treatment allows one to achieve a good cohesion between the implants and a body tissue. The latter allows the conclusion that biocompatibility of the dental titanium implants produced by can be improved using HPPIB treatment

Surface treatment of dental implants with high-power pulsed ion beams

The objective of the present research is development of НРРІВ technology for surface processing of compact components with a complex shape. The surface state of the dental implants from titanium alloys before and after irradiation and long time operation was investigated by Auger electron spectroscopy, scanning electron microscopy, X-ray structural analysis, optical metallography methods. It is shown that the homogeneous state in the surface layer of titanium alloys is formed due to the irradiation (carbon ions and protons, energy of ions is equal to 300 keV, density of ion energy in a pulse achieves 1-5 J/cm^). This state is characterized by a low amount of the impurities and a fine dispersional structure formed as a result of high speed crystallization. Thus, HPPIB irradiation of the dental implants leads to formation of developed microrelief and the decrease of impurities content on the surface. As a result, this treatment allows one to achieve a good cohesion between the implants and a body tissue. The latter allows the conclusion that biocompatibility of the dental titanium implants produced by can be improved using HPPIB treatment

The effect of crater creation on the fatigue strength and corrosion resistance of refractory alloys irradiated by high-power pulsed ion beams

The influence of high-power pulsed ion-beann (HPPIB) irradiation and various methods of preliminary surface treatment on crater creation was examined with the use of Auger electron spectroscopy, X-ray diffraction analysis, and scanning electron microscopy. The crater distribution density, sizes and shape, along with the microhardness and chemical composition Inside and out side craters were determined. The targets from refractory alloys treated with HPPIBs under the Irradiating conditions (Ion energy - E=300 keV; pulse duration - т=50 ns; the ion current density in a pulse - j=120-220 A/cm^, the number of pulses - n=1-100; Temp accelerator), when crater creation takes place on the surface of refractory alloys, were subjected to the fatigue and corrosion tests. It was determined that crater creation results in the catastrophic fracture of the irradiated samples during a cycle load In air at operating temperature. In this case the nucleation of fracture lies into the locality of formed craters. Furthermore, corrosion tests have shown that titanium alloys Irradiated by HPPIBs under the condition of crater creation were subjected to the pitting corrosion mechanism in seawater at thermocycling from 500 to 20 °C. According to the fatigue and corrosion test results, the adjoinity and dent-shape craters are the most dangerous under the cycle load