The paper describes a new method for obtaining a permanent connection of titanium with tool steel and subsequent high-temperature treatment with high-frequency currents in the air. As a result of thermal treatment, a hard and wear-resistant layer of titanium dioxide was formed on titanium. The resulting metal oxide ceramic was tested as a coating for metalworking (cutting) tools. After the preliminary tests, the morphology of the wear of the cutting edges was studied and two wear variants were established – abrasion and shearing. The nature of wear depended on the heat treatment modes and the thickness of the solid layer.
The treatment with high frequency currents (HFC) is traditionally used to improve the mechanical properties of metal products, in particular hardness and wear resistance. A new method of carburization of titanium samples in a solid carburizer using HFC is proposed in the work. The temperature of the carburization is characterized by a wide range from 1000 to 1400 °C. As a result of thermochemical treatment, a hard coating of TiC (H ≥ 20 GPa) with a microstructure (d = 7-14 μm) consisting of nanoparticles (d = 10-12 nm) is formed on the titanium surface. These coatings are widely used in friction pairs for various purposes, including machinery, instrumentation and medicine.
In order to create highly efficient medical systems and measuring biosensors, an approach is frequently used, in which the constructive basis of the product is made of a high-strength biocompatible material (titanium, stainless steel), and the functional layer is made of a more expensive metal (Ta, Zr, Au, Pt, etc.) or ceramics (Ta2O5, ZrO2, CaTiO3, etc.). For a strong connection, e.g. titanium with tantalum, it is proposed to use diffusion butt welding. The heat generated by passing electric current (I is not less than 1.95-2.05 kA, P – not less than 9 kW, t = 250-1000 ms) and applied pressure (30-50 MPa) ensure an integral connection. To improve the quality of the joint, i.e. to exclude cracks and tightness, it is necessary to choose the right combination of the thickness of the welded parts. It was established that when titanium (2 mm thick) and tantalum (0.1-0.5 mm) are combined, a better Ti-Ta welded joint is formed when tantalum foil is used (0.5 mm). Here the distribution of hardness over the cross section of the sample, including the welding areas, is uniform and has no extremely high residual stresses of the tensile type.
In the course of high-temperature treatment with high-frequency currents (HFC) in the range from 600 to 1300 °C, carbon and tool steels are strengthened. After the heat treatment the hardness reaches 64-70 HRC for carbon steel (carbon content 0.4-0.5%) and 68-71 HRC for tool steel 1.3343 (R6M5 steel analogue with 0.9-1.0% C content, W – 5-6 wt%, Mo – 3.5-5.3 wt%, V – 1.3-1.8 wt%, Cr – 3.8-4.3 wt%, Mn+Si – 0.5-1 wt%, Fe – balance). The resulting structure is a carbide network, and in the case of tool steel – complex carbides around a high-strength martensitic phase.
Research results on the chemical composition and surface morphological characteristics of zirconium products after machining and treatment with high-frequency currents are described. It was established that at the temperature range from 600 to 1200 °C and duration of heat treatment from 30 to 300 seconds oxide coatings consisting of nano-grains are formed.
The study focuses on high-performance combined electro-spark alloying of titanium and titanium alloy (VT1-0, VT16) surface and porous matrix structure oxidation. The metal-oxide coatings morphology is the result of melt drop transfer, heat treatment, and oxidation. The study establishes the influence of technological regimes of alloying and oxidation on morphological heterogeneity of biocompatible layered metal-oxide system Ti-Ta-(Ti,Ta)xOy. It was found that during electro-spark alloying the concentration of tantalum on the titanium surface ranges from 0.1 to 3.2 at.%. Morphology of the deposited splats is represented by uniformly grown crystals of titanium and tantalum oxides, which increase from nano- to submicron size.
Prospective composite bioceramic titania coatings were obtained on intraosseous implants fabricated from cp-titanium and medical titanium alloy VT16 (Ti-2.5Al-5Mo-5V). Consistency changes of morphological characteristics, mechanical properties and biocompatibility of experimental titanium implant coatings obtained by oxidation during induction heat treatment are defined. Technological recommendations for obtaining bioceramic coatings with extremely high strength on titanium items surface are given.
Using scanning electron microscopy the crystalline structure of porous oxide coatings produced by air-thermal oxidation of orthopedic implants of alloy 12Cr18Ni9Ti at the temperatures of 350 and 400 °C and duration of 1.5 hours was studied. In vivo tests revealed that the resulting coatings promote successful engraftment of thermally modified implants in the body with highly efficient interaction between morphologically heterogeneous coatings and surrounding bone tissue.
Prospective composite bioceramic titania coatings were obtained on intraosseous implants fabricated from medical titanium alloy VT16 (Ti-2.5Al-5Mo-5V). Consistency changes of morphological characteristics, physico-mechanical properties and biocompatibility of experimental titanium implant coatings obtained by oxidation during induction heat treatment are defined. Technological recommendations for obtaining bioceramic coatings with extremely high strength on titanium items surface are given.
The article describes prospective composite biocompatible titania coatings modified with hydroxyapatite nanoparticles
and obtained on intraosseous implants fabricated from commercially pure titanium VT1-00. Consistency changes of
morphological characteristics, crystalline structure, physical and mechanical properties and biocompatibility of
experimental titanium implant coatings obtained by the combination of oxidation and surface modification with
hydroxyapatite during induction heat treatment are defined.
The project of a microsatellite intended for remote exploration of the atmosphere, ground and sea surface is considered. The realization of hardware part of payload of the satellite is based on the idea to use the turnable acousto- optical filter in ultra-violet and visible ranges of frequency enabling to ensure the programmed varying of one with (Delta) (lambda) less than 1 nm in area 0.2 divided by 0.9 mkm and using the counter of photons with high spatial resolution as a recording sensitive sensor. The given approach permits us to ensure the design realization of the small-size space platform, not requiring three axis precise orientation and stabilization of picture on sensor, which simultaneously is performing the role of star-tracker for detection of the satellite attitude motion.
The opto-electronic system for Earth observing from the space based on the tunable acousto-optic filter and the time-position counter of separate photons is considered. The possibility to reach the high spectral and spatial resolutions without wide-aperture optics and complex systems of control is shown.
Automatic high precision laser scanner has been manufactured. It consists of acousto-optic deflector (AOD), optics, drive power generator connected with computer and laser. Two modifications of laser scanner were developed. The first modification has two AODs manufactured from TeO2 crystal with the following specification: the number of resolvable spots is 500*500, access time is 15 microsecond(s) ec, aperture dimensions equal to 10*10 mm2, acoustic center frequency is 75 Mhz for visible and 34 Mhz for IR spectrum, input optical polarization is linear, maximum optical efficiency for one AOD is 90%, drive power is 1 W per one AOD. The second modification has one XY-dimensional AOD manufactured from KRS-5 crystal with the following specifications: spectral range - (0.6 - 1.1) (mu) , input optical polarization - any, active aperture - 6*6 mm2, access time - 7 microsecond(s) , acoustic center frequency - 100 Mhz, RF input impedance - 50 ohms.
An instrument comprising the optical unit including the objective lens and acoustic-optical filter, detector, and electronic unit interfaced with the IBM PC AT has been designed and manufactured.
Description of a class of heuristical algorithms for the time-coordinate data sequential analysis providing continuous output of data and eliminating the image blur is presented. The time- coordinate data make up a flux of coordinates and detection moments of input radiation photons detected by the lately developed new generation of photo-receivers.
Acousto optic filters (AOF) with optical size approximately 8 - 10 mm for visible and ultraviolet spectrum on the base of TeO2 and KH2 PO4 crystals correspondingly are developed and manufactured. The spectral resolution is better than 1 nm. The frequency bandwidth of both filters is 55 - 90 MHz, that allows us to use the only high frequency generator with two different power amplifiers. Acoustic power level for the AOFs on the base of TeO2 and KH2PO4 was about 1 W and 5 W, respectively. The optical tuning is carried out by means of a computer program.
The paper deals with different aspects of utilizing new technologies in the ecological monitoring systems. Underlying the article are the results of scientific research and original work-outs by the Institute for Mathematical Modelling of the Russian Academy of Sciences and the Science and Technology Center `REAGENT' in the field of vacuum, microchannel plate, laser and transputer technologies. Considered in the present work is the laboratory base of IMM RAS - STC `REAGENT' for interpreting the monitoring data and debugging the devices created on the basis of these technologies. As an example illustrating the possibilities of the new technique in monitoring, an important task of detecting the space debris is put forth.
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