scholarly journals Functional composite electrochemical coating Ni-Co-Al2O3 -an alternative to chromium plating

2021 ◽  
Vol 2131 (4) ◽  
pp. 042022
Author(s):  
K Ovchinnikova ◽  
I Zhukova ◽  
L Degtyar

Abstract The physico-mechanical properties of composite electrochemical coatings (CEC) nickel-cobalt-aluminum oxide were investigated depending on the electrolyte parameters and electrolysis conditions. The previously developed low-concentration chloride electrolyte for nickel plating was used as an electrolyte to replace environmentally hazardous chromium plating electrolytes containing hexavalent chromium, which is prohibited by the laws of many countries. The wear resistance of the obtained CEC was determined on a three-ball friction machine. This made it possible to establish that the wear resistance of the CEC exceeds the wear of chrome coatings in dry friction mode by 2-2,5 times and is comparable to chromium in the friction mode with lubrication. In the dry friction mode, the higher wear resistance of the nickel-cobalt-alumina coating is explained only by the higher hardness of the latter. Probably, upon destruction of the coating, the particles of the alloying addition act as a solid lubricant, which causes an increase in the resistance of the CEC during wear. The microhardness of the CEC was determined using a PMT-3 microhardness tester and amounted to 6-25 GPa. The microhardness value was influenced by the concentration and properties of the dispersed phase, as well as the electrolysis conditions - the temperature and pH of the electrolyte, and the cathode current density. “Corrodcote” test was used in the study of corrosion. According to its data, the corrosion resistance of CEC is 2-3 times higher than the corrosion resistance of chromium deposits. The results obtained make it possible to recommend the developed functional CEC of nickel-cobalt-alumina instead of chromium coatings as corrosion- and wear-resistant.

2020 ◽  
Vol 4 (53) ◽  
pp. 60-64
Author(s):  
Evgeniy V. ASTRASHAB ◽  
◽  
Мarat А. BELOTSERKOVSKY ◽  
Alexander N. GRIGORCHIK ◽  
Vladimir A. KUKAREKO ◽  
...  

The structural-phase state and tribotechnical properties of gas-thermal coatings made of Ni-Cr-Al pseudoalloy are investigated in the initial state and after annealing in the temperature range of 550-650 °С with holding time of 20–60 min. It is shown that in coatings sprayed by the method of high-speed metallization of wires made of Х20Н80 (Kh20N80) and aluminum АД-1 (AD-1), the phase composition includes γ-(Ni, Cr, Fe), Al and Al2O3. It is found that high-temperature annealing of Ni-Cr-Al coatings leads to the precipitation of intermetallic compounds Al3Ni, Ni2Al3, Ni3Al, and NiAl in them, as well as to an increase in the porosity of the coatings up to ≈15–20 vol.%, which is associated with the implementation of the Frenkel and Kirkendall effects. Tribotechnical tests of coatings are carried out according to the scheme of the reciprocating movement of the sample along the plate counterbody in the dry friction mode at a load of 1.5 MPa. It is shown that as a result of the annealing of the coatings, an increase in their wear resistance under dry friction conditions is registered up to 24 times in comparison with the initial state. In particular, the intensity of mass wear of the Ni-Cr-Al coating in the initial state is 28.7 × 10–3 mg/m, and those subjected to annealing at 600 °C for 60 min — 1.2 × 10–3 mg/m. Based on the carried out multifactorial experiment, it is found that the maximum wear resistance of Ni-Cr-Al-pseudo-alloy coatings under dry friction conditions is achieved as a result of their annealing at temperatures of 630–640 °С and a holding time of 40–50 min, which is associated with the release of large number of dispersed intermetallic phases Ni3Al and NiAl with a relatively insignificant increase in the porosity of the coatings.


2019 ◽  
Vol 19 (1) ◽  
pp. 31-37 ◽  
Author(s):  
L. A. Degtyar ◽  
I. S. Ivanina ◽  
I. Yu. Zhukova

Introduction.The electrodeposition of composite electrochemical coatings from electrolyte-colloid nickel plating containing ultradisperse zirconium boride powder is studied. The work objectives are as follows: to study mechanical-and-physical properties of the composites based on nickel and nanostructured zirconium boride, and to determine optimal conditions for the application of such electrochemical coatings.Materials and Methods.Microhardness of composite electrochemical coatings was measured using PMT-3 microhardness tester on samples with the layer thickness of 30 μm under the indentation load of 100 g. A three-ball machine was used to determine wear resistance of the coatings. Sample tests were carried out under dry friction modes and with the use of 3% RV coolant. WSD values were measured by MIR-3 TU 3-3.1954-86 microscope. To determine the internal stresses in the coating, we used a flexible cathode method up to GOST 9.302-88.Research Results.The electrolyte-colloid composition and modes of electrodeposition of composite nickel - nanostructured zirconium boride coatings are developed. Mechanicaland-physical properties (microhardness, wear resistance and internal stresses) of the obtained composite electrochemical coatings are analyzed. Recommendations for use of the developed electrolyte and the application of a composite coating on machine parts for their surface hardening are formulated.Discussion and Conclusions. Ni–ZrB2 CEC (composite electrochemical coating) has high microhardness (10–11 hPa at the indentation load of 100 g), which exceeds the microhardness of pure nickel by 1.5–2 times. As the microhardness increases, the internal stresses ofNi–ZrB2 CEC decrease. The proposed coatings were compared to chromium ones deposited from the environmentally hazardous electrolytes. The wear resistance ofNi–ZrB2 CEC is 2–5 times higher than that of chromium coatings. Thus, instead of chromic coatings, it is recommended to use the proposed composition for surface hardening of parts of the specialty machinery and industrial equipment


Alloy Digest ◽  
1971 ◽  
Vol 20 (8) ◽  

Abstract REYNOLDS 390 and A390 are hypereutectic aluminum-silicon alloys having excellent wear resistance coupled with good mechanical properties, high hardness, and low coefficients of expansion. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, and machining. Filing Code: Al-203. Producer or source: Reynolds Metals Company.


Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.


Alloy Digest ◽  
1969 ◽  
Vol 18 (12) ◽  

Abstract AISI C1060 is a high-carbon water or oil hardening tool and spring steel recommended for heavy machinery parts, shafts, springs and miscellaneous tools requiring strength and wear resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: CS-32. Producer or source: Carbon and alloy steel mills.


Alloy Digest ◽  
1979 ◽  
Vol 28 (12) ◽  

Abstract Copper Alloy No. 878 is a copper-zinc-silicon alloy for die castings. Among the brass die-casting alloys, it has the highest strength, hardness and wear resistance; however, it is the most difficult to machine. It is used where very high requirements must be met for strength and wear resistance. Its many applications include tools, pump impellers, gears and marine hardware. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-386. Producer or source: Copper alloy producers.


Alloy Digest ◽  
2014 ◽  
Vol 63 (12) ◽  

Abstract UGI KC35N is a nonmagnetic nickel-cobalt-chromium-molybdenum alloy with a fully austenitic structure. This datasheet provides information on composition, physical properties, elasticity, and shear strength. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-124. Producer or source: Schmolz + Bickenbach USA Inc..


Alloy Digest ◽  
2009 ◽  
Vol 58 (9) ◽  

Abstract Carpenter ACUBE 100 Alloy is cobalt-base and exhibits corrosion resistance and wear resistance. The alloy was designed as direct replacement of beryllium copper alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion and wear resistance as well as forming, heat treating, and machining. Filing Code: CO-117. Producer or source: Carpenter Specialty Alloys.


Alloy Digest ◽  
1977 ◽  
Vol 26 (1) ◽  

Abstract NUCALLOY 45 is a nickel-chromium-boron alloy which derives superior wear resistance from the presence of hard nickel borides (and to a lesser extent chromium carbides) tightly held in a nickel-rich matrix. It is used in many commercial applications because of its toughness and high resistance to attack by many chemicals. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating, machining, and joining. Filing Code: Ni-238. Producer or source: Stoody Company.


Alloy Digest ◽  
2013 ◽  
Vol 62 (6) ◽  

Abstract ToughMet 2 CX is a Cu-9Ni-6Sn alloy that combines low coefficient of friction with wear resistance. ToughMet alloys are a line of spinodal hardened Cu-Ni antigalling alloys for bearings capable of performing with a variety of shafting materials and lubricants. The alloys combine a high lubricity with wear resistance in these severe loading conditions. ToughMet 2CX in the cast and spinodally hardened (CX) condition exhibits tensile strength in excess of 724 MPa (105 ksi) and hardness exceeding HRC 27 with excellent machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming. Filing Code: Cu-819. Producer or source: Materion Brush Performance Alloys.


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