| SM ISO690:2012|
SIDELINIKOVA, Svetlana; IAPONTSEVA, Iu.; VOLODINA, Galina. Corrosion properties of Co-Mo and Co-Mo-P alloys. In: Materials Science and Condensed Matter Physics. Editia a 7-a, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, p. 300.
|Materials Science and Condensed Matter Physics
Editia a 7-a, 2014
Conferința "Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 16-19 septembrie 2014
Pure molybdenum coating cannot be electrodeposited from aqueos solutions it readly codeposits with iron, cobalt, nickel, forming an alloy. Alloy electrodeposition widly employed in the production of new materials with specific mechanical, chemical and phisical properties. The indused codeposition molybdenum with cobalt to obtain metalic coatings with useful properties, such as hardness, catalytic and magnetic properties . Here were examined corrosion resistence Co-Mo and Co-Mo-P alloys electrodeposited from solutions : 1.100 g/l CoSO4 ·7H2O, 20 g/l Na 2MoO4· 2H2 O, 35 g/l H 3C 6 H 5O7 , 35 g/l Na2E DTA, pH = 4, t =20o C. 2. 0, 6 mol /l CoSO4·7H2O, 0,3 mol / l H3C6H5O7·H2O, 0,02 mol. / l Na2MoO4 ·2H2O, 0,1mol /l NH4H2PO2 ·H2O, pH = 6, t =20 C. The deposition occurred in the range of curent densities 2 –10 A/dm2. Corrosion properties of Co-Mo and Co-Mo-P alloys in neutral media with cloride-iones (7 g/l Na2SO4 and 7 g/l NaCl) were studied by methods of electrochemical impedance spetroscopy and voltammetry using sistem AUTOLAB (GPSTAT 20 +FRA ) with program GPES 4,9 and FRA 4,9. Corrosion parameters was found from analysis voltammetric curves and spectrums of electrochemical impedance. Morfology and alloys composition were studied by scanning electron microscope (TESCAN) with system for local chemical analysis (ICA Energy EDX).The structure of electrodeposits were studied by X –ray phase analysis with aplication of diffractometer (ДРОН –3) by Ø/2Ø method. It was shown that curent density increases from 2 to 10 A/dm2, content of molybdenum in Co- Mo and Co -Mo –P alloys increase, but content of P decrease. The content of Mo in Co-Mo alloys are 6,9 – 12 at. % and in Co-Mo-P alloys – 3 –7,5 at. % and at. % of P = 3,3 – 1,9. Results of X-ray diffractometry are shown the increase of texturing coatings obtained at curent density 5 – 10A/dm2 and it is very important for corrosion characteristics of Co-Mo and Co-Mo-P alloys. It has been found to depend corrosion resistance of testing simples from composition and structure. Corosion parameters of Co-Mo electrodeposited at 2 - 10 A/dm2 : Icor. = 2,6 – 20.2 ·10-5 A, Ecor. = -0,653 –0,786 V, Rcor. = 0,5 –1,12·103 Om, Vcor. - =5,4 - 24·10-5 mm/year and of Co-Mo-P alloys ellectrodeposited at 5 – 15 A/dm2: Icor. =1,2 – 15,6·10-5A, Ecor. = –0,674 – 0,779 V, Rcor. = 3,7 –1,58·103 Om, Vcor. ~ =5·10-5 mm/year. It is shown that induced electrodeposition molybdenum with cobalt is one method to achive materials with high corrosion resistence.