372595883

JPRS-UMS-92-003 16 March 1992

COATINGS

21

a titanium surface that occur when it is subjected to laser surface alloying with iron and nickel. Specimens of VTl-0 commercial-grade titanium prepared by annealing in a vacuum at a temperaturę of 970 K for 2 hours were studied. The electrolyte method was used to apply the alloying materials. To improve adhesion, a copper coating 0.3 to 0.4 pm thick was used as an underlayer. After coating the specimens were subjected to vacuum heating at a temperaturę of 870°C for 20 minutes. The resultant coating layer measured 10 pm in thickness. The coated specimens were fused by continu-ous-wave laser radiation at powers of 220 and 630 W. The treatment was conducted with fusion of the surface in a stream of commercial-grade nitrogen at a pressure of 0.25 atm. A Katun C0₂ laser and a spot diameter of 2 mm were used. The speed at which the beam was moved along the specimen surface was varied from 30 to 1,000 mm/min. The studies performed indicated that increasing the speed at which the beam is moved along the specimen surface results in a morę uniform surface structure and makes it possible to produce a relatively finely disperse structure with improved physicomechan-ical properties. At high beam speeds no melt zones were observed (thanks to the Iow temperaturę factor). Figures 5, table 1; references 7: 6 Russian, 1 Western.

Protective Diamondlike Films on Quartz

927D0089K Moscow FIZIKA IKHIMIYA OBRABOTKI MATERIALOY in Russian No 6,

Nov-Dec 91 (manuscript received 11 Mar 90) pp 113-116

[Article by S.M. Klotsman, A.S. Kovsh, L.M. Kovsh, Ye.V. Zuzmina, R.R. Mukhametkhaziyev, S.A. Plotni-kov, I.Sh. Trakhtenberg, and L.M. Feygin, Sverdlovsk]

U DC 539.216.2:514.26-162

[Abstract] The authors of the study reported herein examined selected performance characteristics of protec-tive diamondlike quartz coatings produced by the method of ion-condensation destruction of hydrocar-bons. The said method, which is characterized by a high ion concentration in the beam, makes it possible to produce films with minimum internal stresses. A graphite chamber (cathode) containing two copper water-cooled anodes was used as the ion beam source. One of the chamber walls was fashioned in the form of a grid through which an ion beam measuring 70 x 150 mm² was drawn into the chamber. High-purity (99% pure) propane was used as the working gas. Fused polished quartz and quartz coatings on glass produced by electron beam sputtering served as substrates. Germa-nium substrates were also used in some of the experi-ments. The working chamber was evacuated to create a pressure no worse than 2 x 10*⁴ Pa. Before the coating process began, the substrates were cleaned in an argon discharge. During the coating process the propane pressure was varied from 8 x 10*³ to 5 x 10‘² Pa, the discharge voltage was varicd from 1.2 to 2 kV, and the discharge

current was varied from 0.15 to 0.66 A. After the sputtering the specimens were held in a vacuum for at least 30 to 40 minutes, after which air was allowed to enter the chamber. The method of nuclear reactions on a deuteron beam with an energy of 900 keV was used to dctermine the residual gas impurity (oxygen and nitrogen) profile of the diamondlike coatings. The optical properties of the diamondlike coating were found to be virtually independent of sputtering regimen. The diamondlike coatings applied to germanium had a higher refractivity than those on quartz (2.17 +/- 0.06 and 2.02 +/- 0.04, respectively). The diamondlike coatings’ absorption was found to decrease as the wavelength was increased. The condensation ratę was found to be a linear function of the discharge current. The diamondlike coatings on quartz were characterized by a refrac-tivity of 2 and a transparency in the infrared rangę. The diamondlike coatings were found to afford a certain amount of protection to the quartz substrates to which they were applied. Specifically, they reduced the substrates’ friction coefficient by a factor of 1.5, caused a severalfold increase in resistance to the effccts of abra-sive particles, and provided stability to moisture, heat shock, and heating to 200°C. The effectiveness of the diamondlike coating was not limitcd to the properties of the films themselves; rather, the quality of its mesh with the substrate (which increased as the ion beam energy increased) was also important. Figures 3, tables 2; references 6: 5 Russian, 1 Western.

Morphologic Changes in the Structure of Composite Conglomerated Powders During Plasma Sputtering and Their Effect on Coating Structure

927D0089I Moscow FIZIKA I KHIMIYA OBRABOTKI MATERIALOV in Russian No 6, Nov-Dec 91 (manuscript received 22 Jan 91) pp 84-89

[Article by A.K. Tolstobrov, M.Yu. Zashlyapin, and B.V. Mitrofanov, Nizhniy Tagil and Sverdlovskj

UDC 621.793.72:533.9

[Abstract] The authors of the study examined the morphologic changes occurring in composite conglomerated powders during plasma sputtering and the effect of these changes on coating structure. Five conglomerated powders were tested. Their compositions (% by mass) were as follows: Powder 1, 50TiC_o.₅N_O5 + 50Ni; powder 2, 50TiC_o.₅N_o 5 + 25Ni + 25Mo; powder 3, 35TiC₀₅N₀ 5 + 49Ni + 16Mo; powder 4, 35Ti₀ 9Zr₀.iCo.5No.5 + 49Ni + 16Mo; and powder 5, 35TiC₀ 5Ńo.5 + 52Ni + 13Cr. The structure of particles produced by sputtering powders in a water bath from a distance of 200 to 300 mm was studied. The techniquc of plasma sputtering on a UPU-3D plasma unit was used to sputter the powders and apply composite coatings to substrates of type 45 Steel. An argon-nitrogen mixture was used as the plasma-forming gas. A Neophot-21 microscope, Camebax x-ray spectroscope, and PMT-3 hardness tester were used for