848 Metal coatings Werkstoffe und Korrosion 29, 835-850 (1978)

2701 Fluorocarbon laminate sheet lining of high chemical resistance. P. J . Bruckshaw. Anticorr. Meth. Mater. 25 (1978) 8, 12-13.

In order t o overcome difficulties involved in the application of FEP and PVF2 linings to reaction vessels, a glasscloth-PVF2 material has been developed; this material is bonded t o the vessel using a high temperature epoxy adhesive. PVF2 welding rods are used t o join the sheets with a hot air gun (continuity is checked by high voltage spark test), and after welding a capping strip is applied. The chemical resistance of the lining is the same as as that of the normal PVFZ, thermal cycline and shock resistance if from -60 to 180 "C. - Pu.

2702 Resistance of polyimides against working fluids. N. A. Grishin, V. P. Kuselev. T. S. Shcherbakova. Plast. Massy (1978) 5, 75.

In the framework of an investigation into the resistance of polyimides to hydraulic fuel media the behaviour was tested in fuel oil, lubricating oil and hydraulic fluids at normal and elevated (200 to 250 "C) temperatures. Specimens previously heat treated do not exhibit weight o r dimensional changes after 2400 hours a t room temperature; the specimens tested at 200 and 250 "C, however, show certain weight and dimensional changes which are mainly attributed to temperature effects. - Pu.

2703 Progress in the field of epoxy moulding compounds. P. Tschanz.

A review is given of the technical properties characterizing epoxy mould- ing compounds: resistance to microcrack formation; no after-shrinking; high adherene to metal fittings; resistance to thermal degradation; stiff- ness; good insulating properties; resistance to sliding wear; high corrosion resistance (very good resistance in 46% sodium hydroxide, potable water, 5% phosphoric acid, distilled water, saturated sodium chloride solution, 17% calcium chloride, 1070 ferric chloride, isopropanol, 2070 zinc chlo- ride, 20% tin chloride, 10% sodium sulfide, 570 potassium permanganate cyclohexane; good resistance in 20, 5 and 2% sodium hydroxide, 5% hy- drochloric acid, 10% acetic acid, concentrated formaldehyde, toluene, ammonium hydroxide (concentrated and 5%). 10% sodium carbonate; not resistant in 70% sulfuric acid, concentrated hydrochloric acid, 20 and 5% nitric acid, sodium hypochlorite (14 and 17%), tetrahydrofurane, concentrated phosphoric acid, hydrogen peroxide, aniline, methylethyl ketone, monochlorobenzene). - Pu

2704 Short term testing the weathering resistance of PMMA in different test devices. J. Hennig, H. Horn. Kunststoffe 68 (1978) 8 , 494-497

An expansion of the capacities available for short term (accelerated) weathering may be achieved by increasing the amount of UV radiation. A comparative study of various Xenotest devices shows that comparable results may be achieved provided suitable filters are used so that the radia- tion spectra become available. In the case of PMMA (high molecular weight, with flame retardants), PMMA modified by addition of polybutyl acrylate) and high molecular weight PMMA in various colour shades it is shown that there exists no analogy between the change of physical proper- ties (tear resistance, notch toughness) and colour changes during natural and artificial weathering. - Pu.

2705 Polyamide membranes for ultrafiltration. S. I. Kuperman,

Kunststoffe -Plastics 25 (1978) 7, 43 -49.

0. I. Nachinkin, I. G. Puban. Plast. Massy (Moscow) (1978) 5, 26-27.

The porosity of the filter membranes depends on the type of manufac- ture: the lower the phase separation velocity in the starting system, the higher mechanical strength but the lower porosity. Lowest porosity is obtained when films are prepared from melts, while highest porosity is found in foils obtained by precipitation from solution; the degree of amorphy is proportional to film porosity. The films are resistant to dis- tilled water. 2% potassium hydroxide, aqueous solutions of monoethanoi amine and glycerin. dimethyl formamide and dioxane. - Pu.

2706 Nondestructive evaluation of strength degradation in glass-reinforced plastics as a result of environmental effects. M. Meron, Y. Bar-Cohen, 0. lshai. J. of Testing and Evaluation 5 (1977) 5, 394-396.

Destructive and nondestructive tests were conducted on glass-reinforced plastic specimens after degradation by immersion in hot water for various periods. Ultrasonic attenuation was found to correlate well with normal- ized residual strength data obtained from destructive tests. From the com- parison of the mechanical and ultrasonic test results the following conclu- sions can be made. The ultrasonic attenuation testing method is an effec- tive tool in assessing GRP degradation after immersion in hot water for various periods of time. Good correlation is obtained between the ultra- sonic attenuation measurements and the normalized residual strength data. The ultrasonic attenuation is found to he a better indicator of de- gradation in GRP laminates than mechanical testing. - Pu.

Metallische Uberzuge/Metal coatings

2707 Chemical-Corrosion and Hygienic Aspects of the Use of Hot- Galvanized Threaded Pipes in Domestic Plumbing for Drinking Water. Gerda Burgmann, Werner Friehe, and Wilhelm Schwenk. Grros . Prev. Control, Feb. 1978, 25, (I), 7-1 1 rin F n v l i q h l

The materials available for domestic plumbing pipes a r e discussed. The hot-dip method used produces a coating composition of Zn -97 and Fe 3%, with Pb 0. 8 and Cd 0.01"~ as trace elements. The factors affecting corrosion of the Zn coating in flowing and stagnant water a r e briefly reviewed and 0-contg. soft water is identified as a limit of application. The impairment of tas te is attributed to acid formed by the hydrolyzable Zn salts. Zn, Pb, and Cd levels were measured over a five year period and compared to the values recommended by the 1975 German drinking water regulations and to the amounts present in foodstuffs. 30 ref.-R. J. H.

2708 The Corrosion of Alloyed Zinc Coatings in Marine Conditions. E.V.Proskurkin et al . 46-47 [in Russian].

Zashch.Met., Jan.-Feb. 1978,14, (l),

Corrosion tes ts of s 18 months duration in flowing sea water (Black Sea), in a marine atmosphere, and in the splash zone (Caspian Sea) were made with hot-dipped galvanized coatings of 70-80 fim on steel 20 [C 0.17-0.2570] and s teel 3 [C 0.14-0.22%] to determine the effect of separate or combined additions of Mg 0.033-0.065, Ti 0.007-0.014, A1 0.05-0.14, and Cu 0.43% to the melt. The effects of holding at 550 "C for 15 min were studied. In flowing s e a water the corrosion resistance is improved by alloying with Mg, Mg + Al, Ti, Ti + Mg, and particularly by Mg 0.05 + Ti 0.01 + A1 0.085%. Significant further improvements a r e obtained by heat treating the coatings. Alloyed Zn coatings of these types have been introduced for ships' pipework systems.-A.D. M.

2709 The Kinetics and Mechanism of Oxidation of Carburized Electrolvtic Chromium Coatiics. V. I. Arkharov and __.. Sh. Kh.$ar-Mukhamedov. Zaihch.Met., Jan.-Feb. 1978, 14, (l), 3-8 [in Russianj.

Carburizing (8-10 h at 1050 "C in benzene/H or benzene/Ar) increases the oxidation resistance of electrolytic Cr coatings significantly (- 10 times). The high temp. oxidation (1200 "C in a i r ) kinetics depend on the plating and carburizing conditions and on the composition of the steel substrate. Two mechanisms a r e possible: (i) diffusion of residual Cr through the carbide layer outwards along grain boundaries; or (ii) in the absence of residual C r , by chemical reaction causing depletion of C and oxidation of the released Cr. 7 ref.-A. D. M.

2710 Electrochemical hehaviour of galvanized steel reinforcement in concrete. I. Study of the reactions between zinc and calcium hy- droxide. I. Pepenar, E. Pepenar. Rev. Chim. (Bukarest) 29 (1978) 5,445-449.

In a calcium hydroxide solution - which is assumed t o simulate concrete during the initial curing stages - galvanized steel is passivated by the for- mation of a calcium hydroxyzincate layer with simultaneous potential shift toward more positive values. The maximum in the anodic polarisa- tion curve corresponds to a zinc hydroxide layer which is later trans- formed into the hydroxy zincate. The passivation tendency increases with the duration of immersion and with increasing atmospheric oxidation of the zinc. The passive layer reduced the susceptibility t o corrosion by chloride ions. Localized damage to the zincate layer does not result in a deterioration of the protective effect. - Pu.

2711 Decorative Coatings of 'Satinized' Nickel. Gunter K. Schwarz. Galvano Tec.. Aug. 1977,28, (8), 138-140 [in Italian].

The procedures for producing decorative N i electrodeposits with a satin finish a r e described. Four processes a r e noted involving: (i) deposition of Ni with a solid in suspension in the electrolyte; (ii) deposition of an intermediate layer of high opacity and uniform crystallinity; (iii) deposition from an emulsion; and (iv) deposition from finely dispersed solutions, aqueous and organic. A commercial process based on (iv) is described in more detail and operating data a r e given for two types of bath.-P. C. K.

2712 Oxidation Mechanism of a Thin Film of Metallic Tin Deposited on Glass. Chan Duk Thiep, Ts. Bonchev, Nguyen Chi Toa, and S. Peneva. Bulg. J. Phys., 1977,4, (4), 399-406 [in English].

The oxidation mechanism of a thin film of metallic Sn, deposited on glass, was studied by depth-selective Mossbauer spectroscopy. The variation of the phonon spectrum with film thickness was studied, depending on the oxidation conditions. The temp. dependence of the electrical resistivity of the film was obtained for various oxidation states. The resul ts were applied to the elucidation of the structure of Sn oxide surface films.-BA

2713 A New Method for Thickness Deposition Control and Mea- surements of Cylindrical Ferromagnetic Films. V. Mihai

~~ Rev.Roum. Phys., 1977, 22,(7), 771-773 [ i n English]. A note. A method employing the transverse Procopiu effect (TPEJ (M. c t ul . , 1972) for measuring the thickness of cylindrical frrro- magnetic f i lms- and hence for checking the thickness of such films during electrodeposi t ion~is proposed. To make use of the TPE, longi- tudinal alternating and steady circular magnetic fields a r e produced,

Werkstoffe und Korrosion 29, 835-850 (1978) Non-metallic inorganic coatings 849

resp. , by an alternatmg-voltage-energized solenoid wound around, and a wire carrying d.c. threaded through, the cylindncal specimen, the resulting TPE e.m.f,between the ends of the film,and i t s time depen- dence, being displayed on a cathode ray oscilloscope. The dispersion of the weak magnetization direction along the axis of the film can also be determined. Results of experiments on Permalloy (80% Ni- 202, Fej films, length 120 m m and thickness 3 .3 l m , prepared by electrodeposition on a 0 .2 mni dia. glass capillary a r e reported. 8 ref.-R. B.

2714 Black Chromium Plating for Solar Collectors, G. Thomas Robison. Prod. Finish.<Cincinnati), Jan. 1978,42, (4), 38-42 [in Ennlishl.

Lj 1

The prockss cycle for black C r plating of solar collectors i s dis- cussed. Two basic kinds of collectors a r e plated steel and Cu. Both materials a r e similarly processed and, depending on their condition when received, the collector panels can be directly plated o r receive a flash of semibright Ni before black Cr . Inspection and quality con- trol techniques a r e mentioned.-M.A. P.

2715 The Annealing Behaviour of GermaniumGold-Nickel, Germanium-Gol&Platinum and GermaniumGold-Palladium Trilayered Films. T.G. Finstad. Thin Solid Fi lms, 15 Dec. 1977,47, ( 3 ) , 279-290 [in English].

Interdiffusion i n Au-Ge-Ni, Au-Ge-Pt, and Au-Ge-Pd trilayered electron-gun-evaporated thin films on SiO, substrates was investi- gated by backscattering, scanning electron microscopy, and X-ray diffraction. When the amount of Ge i s <lo0 at.-% of that of Ni, Pd o r Pt i n the trilayered films, heat treatment yields laterally uniform two-layered f i lms consisting of a germanide layer and a Au layer. When more Ge is present than i s required to complete the formation of the most Ge-rich germanide (GeNi, GePd, Ge,Pt), the films a r e laterally non-uniform after annealing above o r below the Au-Ge eutectic temp. (356 "C). The behaviour of Au-Ge-Ni on SiO, is com- pared with that observed on a GaAs substrate. 20 ref.-AA

2716 Electrodeposition of Nickel f rom Alkaline Citrate Electro- lyte. 1.-Effect of the Electrolyte Composition on the Catho- dic Processes . Yu.Yu. Matulis. A. P. Karaavichvus. and ~ ~~~.

S.I.Yaskonene. Liet. TSR Mokslu Akad.Darb., 1977, [B], (5(102)), 29-36 [in Russian .

The effect of the concentration of N]iSO,, Na,C,HSO,, and (NH,),,SO,, of DH, and of the cathode potential on the electrodeposition of N1 from Ni'citrate has been investigated. In the absence of (NH,),SO, the c.d. decreased with the addition of Na,C6H,0, and pH increased to 10. However, the addition of small amounts of (NH,),SO, (up to 20 g/ l . j gave a large increase in the c.d. Under these conditions an increase in pH to 8 .2 gave an increase in the c.d., but for larger values of the pH the c.d.fel1. The sequence of the cathodic reactions was not established, but deposition of Ni from Ni citrate is very improbable. 16 ref.-P.H.M.

2717 Electrodeposition of Titanium from Non-Aqueous Solutions. A. M. Levinskene, L. E. Simanavichyus, and V. Ya. Akimov. Liet. TSR Mokslu Akad. Darb., 1977, [B], (5(102)), 37-46 [in Russian).

Experiments on the electrodeposition of Ti f rom various non-aq. solutions of TiC1, at concentrations 0.1-0.5M a r e reported. When the solvent used was dimethylsulfoxide (DMSO), o r a mixture of this with ethanol, thin films PO. 2 g m thick) were deposited on the cathode. The films contained Ti -20%. Pt , Cu and N i cathodes were used, and the colour of the film depended on the cathode, the Cu and the Ni reacting with the solution. For c.d. between 100 and 1000 A/m2 there was no dependence of film thickness on c.d.or time. Higher c.d. resulted in gas generation. Solutions of TiC1, in other inorganic liquids were tried, but these resul ts in very poor conductivity on the one hand o r gas generation on the other. 31 ref.-P.H.M.

Nichtmetallische anorganische Uberzuge/ Non-metallic inorganic coatings

2718 Preparation and High-Temperature Corrosion of Zirconium Silicide Coatings on Zirconium. M. Caillet. H. F. Ayedi. A. Galerie, and-J. Besson. Rev. Int. Hautes Temp. Refract., 1978.15. (1). 55-62 Tin Frenchl.

Coatings of ZrSi)Zr,Si on Zk were prepared by the deposition of Si from monosilane on heated Zr samples. The oxidation of these coat- ings by 0 or water vapour follows the general ra te law: (Am)n = k t (n 2 1.6). These kinetic resul ts can be explained by the existence of two different silicide layers. At the lowest water vapour pressures, the kinetic behaviour is different; the formation of volatile SiO can account for this phenomenon. The experiments show the good

corrosion resistance of this coating compared with that of pure Zr . For example, in 0 atmospheres, the weight gains a r e - eight times less for silicides than for Zr. 10 ref.-AA

2719 Fabrication and Evaluation of Erosion-Resistant Multi- spectral Optical Windows. R. H. Hopkins el al. J. Appl. Phys., June 1978,49, (6), 3133-3139 [in English].

Thin ZnS claddings can be bonded to ZnSe substrates to form a com- posite window designed to display rain-erosion resistance equivalent to ZnS alone, but with broadband transmittance and scattering levels comparable to ZnSe. Joining of the window components is achieved by means of a thin As-S-Se glass layer, using a technique termed optical brazing. Optical path differences in the composite window are primarily due to heterogeneities in the ZnS and ZnSe components; no degradation in optical quality due to the glass bond is evident. Rain- erosi'on data confirm that the composite window is a s resistant to multiple drop impact damage as monolithic ZnS. 13 ref.--AA

2720 Protective Coatings for Metals by Chemical Vapour Depo- sition. K. K. Yee. English].

Int. Met. Rev., 1978,23, (l), 19-42 [in

The protection of metals using coatings (e.g., of A1,0,, Cr,C,, Ta, TiB,, T i c , TiN, ZrN, ZrC, W, Mo, W,C, etc.)produced by chemical vapour deposition (CVD) is discussed, and the general principles and techniques of the various unified CVD processes a r e examined. Aspects of fundamental studies associated with the deposition process a r e reviewed. The adhesion of coatings i s discussed in detail, with emphasis on the coating/substrate system and the factors which affect the adhesion of coatings. A survey is presented of the available or developed CVD coating systems which are likely to be relevant to protective coatings for metals. This is followed by a review of the applications of some CVD coatings for a variety of operating environ- ments where, for example, protection is required against wear, ero- sion, corrosion, and high-temp. oxidation. The unique characteristics of CVD are discussed and i t s advantages and disadvantages a r e then considered in the light of these characteristics. An assessment i s made of the present situation and future possibilities in the develop- ment and application of CVD protective coatings. 166 ref.--AA

2721 Behavior of Maleic Acid During the Anodization of Y

Aluminum. Michiko Shimura. J. Electrochem. S 3 , Feb. 1978,125, (2), 190-193 [in English].

Anodization of A1 in aqueous maleic acid a t constant current densities showed that the formation of the anodic film took place competitively with the oxidation of maleic acid. In dilute electrolyte, except for the initial short period where the colorless thin film was formed, the over-all current served to oxidize the doubie bond of maleic acid into glyoxal or CO. In concentrated electrolyte, the brownish anodic film was readily formed and became black a s it thickened. The colored film was shown to favor the passage of ionic current and was made up of A1,0, complexed with maleate. The coloration of the film was con- sidered to be induced from carboxylate anion radicals,which were coordinated to the A1 ion a s a ligand, a s in the case of oxalic acid film reported previously. 7 ref.-AA

2722 Selective Studies of Chemical Vapor-Deposited Aluminum Nitride-Silicon Nitride Mixture Films. E.A.1rene. [in English].

S. Zirinsky and J. Electrochem. Soc., Feb. 1978,125, (2), 305-314

Films of aluminum nitride and mixtures of aluminum nitride and silicon nitride have been chemically vapor deposited upon Si and sapphire substrates within the temp. range of 600-1100 "C by the ammonolysis of gaseous aluminum trichloride and silane. Charac- terization of film properties included: film morphology as observed by transmission electron microscopy (TEM), optical properties, dis- solution ra te , residual s t resses , electrical conduction and charge- storage behavior, a s a function of composition and deposition para- meters. Some compositions appeared promising for programable read only memory applications (MIOS-FET) based upon low write- e rase voltages, good fatigue and charge retention properties. 39 ref.

-AA

2723 A Study of Conversion Coating Development on Aluminium in ChromateFluor ide Solutions Using Secondary Ion Mass Spectrometry. M. F. Abd Rabbo, J. A.Richardson, and G . C. Wood. Corros. Sci., 1978,18, (Z), 117-123 [in English].

An Ion Analyzer was used to examine A1 surfaces, covered by 73 nm thick bar r ie r type anodic films, after natural immersion for 1-15 min in a chromate-fluoride conversion coating solution at 293 OK. The conversion coating produced is essentially amorphous Cr-contg. material (probably largely hydrated chromic oxide) but contains a cellular-type structure with A1 and F- (probably a s complex oxy- fluoride) concentrated in the inter-cellular regions. The major role of the F- ion is to remove the initial oxide film, maintain the surface active and permit nucleation and la teral growth of the conversion coating over it. The F- ion is more aggressive towards anodic and