Functional Multi-Nanolayer Coatings of Amorphous Carbon/Tungsten Carbide with Exceptional Mechanical Durability and Corrosion Resistance.

Title Functional Multi-Nanolayer Coatings of Amorphous Carbon/Tungsten Carbide with Exceptional Mechanical Durability and Corrosion Resistance.
Authors N. Nemati; M. Bozorg; O.V. Penkov; D.G. Shin; A. Sadighzadeh; D.E. Kim
Journal ACS Appl Mater Interfaces
DOI 10.1021/acsami.7b08565
Abstract

A novel functional multilayer coating with periodically stacked nanolayers of amorphous carbon (a:C)/tungsten carbide (WC) and an adhesion layer of chromium (Cr) was deposited on 304 stainless steel using a dual magnetron sputtering technique. Through process optimization, highly densified coatings with high elasticity and shear modulus, excellent wear resistance, and minimal susceptibility to corrosive and caustic media could be acquired. The structural and mechanical properties of the optimized coatings were studied in detail using a variety of analytical techniques. Furthermore, finite element method simulations indicated that the stress generated due to contact against a steel ball was distributed well within the coating, which allowed the stresses to be lower than the yield threshold of the coating. Thus, an ultralow wear rate of ?10(-12)mm(3)/N mm could be achieved in dry sliding conditions under relatively high Hertzian contact pressures of ?0.4-0.9 GPa. The amorphous and pinhole-free structure of the individual layers, sufficient number of pairs, and the relatively dense stacked layers resulted in significant polarization resistance (Z? = 5.5 × 10(6) ? cm(2)) and increased the corrosion resistance of the coating by 10-fold compared to that of recently reported corrosion-resistant coatings.

Citation N. Nemati; M. Bozorg; O.V. Penkov; D.G. Shin; A. Sadighzadeh; D.E. Kim.Functional Multi-Nanolayer Coatings of Amorphous Carbon/Tungsten Carbide with Exceptional Mechanical Durability and Corrosion Resistance.. ACS Appl Mater Interfaces. 2017;9(35):3014930160. doi:10.1021/acsami.7b08565

Related Elements

Tungsten

See more Tungsten products. Tungsten (atomic symbol: W, atomic number: 74) is a Block D, Group 6, Period 6 element with an atomic weight of 183.84. The number of electrons in each of tungsten's shells is [2, 8, 18, 32, 12, 2] and its electron configuration is [Xe] 4f14 5d4 6s2. Tungsten Bohr ModelThe tungsten atom has a radius of 139 pm and a Van der Waals radius of 210 pm. Tungsten was discovered by Torbern Bergman in 1781 and first isolated by Juan José Elhuyar and Fausto Elhuyar in 1783. In its elemental form, tungsten has a grayish white, lustrous appearance. Elemental TungstenTungsten has the highest melting point of all the metallic elements and a density comparable to that or uranium or gold and about 1.7 times that of lead. Tungsten alloys are often used to make filaments and targets of x-ray tubes. It is found in the minerals scheelite (CaWO4) and wolframite [(Fe,Mn)WO4]. In reference to its density, Tungsten gets its name from the Swedish words tung and sten, meaning heavy stone.

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