This paper presents the results of experimental research concerning the laser-plasma coating of steel substrate with the following powder grades: AP-FeCr4MnSiB (Fe71.75C4.81Cr3.33Si3.54B14.10Mn1.74V0.73), AP-FeCr11Mn4SiB (Fe66.8Mn2.84C2.85Si5.3B11.42Cr10.79), AP-FeNi19Mn10SiB (Fe56.12Ni15.82C1.65Si4.92B12.82Mn8.66) and AP-G14 (Fe29.4Ni32.24C5.32Cr14.78Si4.06B10.22Mo2.8W1.16). As a focusing head was used self-made lateral nozzle for feeding powder. The nozzle was used in conjunction with scanning the laser radiation in the direction perpendicular to the movement of the focusing head. Coated tracks with various nozzle head movement speed (7-20 mm/s) was obtained. The elemental compositions of the resulting coatings were studied. Alloying elements are uniform distributed throughout the coating. During surfacing the powder particles are completely melted and partially mixed with the base material. This leads to increased iron content in the resulting coatings compared with the original powder. The hardness and thickness of the deposited layers were measured depending on the speed of the process. The hardness of the coatings is in the range of 7-12 GPa, the thickness is 0.15-0.7 mm. The wear resistance of the resulting coatings is up to 10 times higher than that of a steel substrate.
The results of laboratory and numerical experiments on propagation of focused intense pulse-periodic and continuous CO2-laser radiation in the absorbing gas and aerosol media are presented. It is established that focal waist of a laser beam is characterized by reduced heat release that is associated with absorption saturation. It is shown that increase of pulse repetition frequency in a train decreases effect of optical breakdown on path transparence since under the condition of constant mean radiation power peak intensity in each pulse decreases and probability of breakdown onset is reduced.
A new method of plasma-chemical synthesis with activation of initial substances by an optical pulsating discharge in high-velocity gas flows is used for the first time to synthesize nanostructured coatings from carbon or silicon carbonitride compounds, synthesize carbon nanoparticles, and for nanostructured modification of the iron surface. Record injection rate (for plasma-chemical methods) of energy into the gas volume (>109 W/cm3), high cooling rate (~1010 K/s), and the possibility of obtaining equilibrium plasma with a temperature of up to 20-30 kK open up wide possibilities for the development of effective laser-plasma nanotechnologies.
The multifunctional laser LOK-3MF has been developed on the basis of the CW laser with DC pumping and cross gas flow1. An optical resonator of the laser has been developed on the SFUR (Self Filtering Unstable Resonator) scheme2. High beam quality is provided by this scheme (full angle divergence is 0.7 mrad on 0.86 power level at beam diameter 30 mm). The laser generates 3 kW output power without any additional equipment. Besides, it is equipped by four accessory units in a feedback arm to provide a variety of operating modes. 1. Single-frequency CW mode with capability of monotone line tuning in bands of 9.4 micrometers and 10.4 micrometers (about 70 lines in all) with maximum output power up to 2.6 kW at line 10P20 and per-unit frequency instability of the order of 10-7. As it as been shown, there is a possibility to reduce a laser line width down to 50 kHz. 2. The mode with simultaneous two-wavelength lasing at 40 pairs of adjacent laser lines with maximum total power up to 2.5 kW. A simultaneous generation of 3 adjacent lines have been observed in 9R branch. 3. A mode with rapid tuning of the generation line (with about 1 microsecond(s) transition time) in combination with an opportunity to form any given spectral-temporal sequence. The generation spectrum and output power are the same, as in mode 1. 4. Repetition-rate Q-switching mode with high peak power (up to 800 kW) and the average one (up to 2.8 kW) with pulse repetition rate control in the range of 1-100 kHz. 5. The repetition-rate Q-switching mode in combination with line-tuning (such as in mode 1) has been developed for selective photochemistry and laser isotope separation. A selection of applications of the laser for material processing and for producing of a new variety of gas discharge - powerful optical pulsating discharge are presented.
A laser has been developed on the basis of the CW CO2 laser with DC pumping and cross gas flow. An optical resonator of the laser has been developed on the SFUR (Self Filtering Unstable Resonator) scheme. High beam quality is provided by this scheme (full angle divergence is 0,7 mrad on 0,86 power level at beam diameter 30 mm). The laser generates 3 kW output power without any additional equipment. Besides, it is equipped by four accessory units in a feedback arm to provide a variety of operating modes. (1) Single-frequency CW mode with capability of monotone line tuning in bands 9,4 microns and 10,4 microns (about 70 lines in all) with maximum output power up to 2,6 kW at line 10P20 and per-unit frequency instability of the order of 10 to the minus 7th. As it has been shown, there is a possibility to reduce a laser line width to 50 kHz. (2) A mode with rapid tuning of the generation line (with about 1 microsec transition time) in combination with an opportunity to form any given spectral-temporal sequence. The generation spectrum and output power are the same, as in mode 1. (3) Repetition-rate Q-switching mode with high peak power (up to 800 kW) and the average one (up to 2,8 kW) with pulse repetition rate control in the range of 1 - 100 kHz. (4) The repetition-rate Q-switching mode in combination with line-tuning (such as in mode 1) has been developed for selective photochemistry and laser isotope separation. The results of the applications of the laser with repetition rate mode to producing of a new variety of gas discharge-powerful optical pulsating discharge are presented.
The performance of a 3 kW CO2 transverse flow laser using a self-filtering unstable resonator configuration is presented. The output beam quality is the same as TEM00 mode stable resonator. The resonator contains nontransmitting optical elements. A facility for Q- switching and line tuning has been developed on the basis of this resonator and the results of preliminary experiments are given.
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