Exploring the Tribophysics and Tribochemistry of MoS2 by Sliding MoS2/Ti Composite Coating Under Different Humidity

Li, Hao; Li, Xia; Zhang, Guangan; Wang, Liping; Wu, Guizhi

doi:10.1007/s11249-017-0824-x

Cited by 41 publications

(23 citation statements)

References 39 publications

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“…Ti improves oxidation resistance, as verified by measuring the same friction with 10.8% Ti across a range of humidities [203]. Lastly, it was found that Ti doped MoS2 performance depends on the counterface material, with ZrO2 being best among brass, GCr15 steel, WC and ZrO2 [195].…”

Section: Tribological Properties Of Doped Mos2mentioning

confidence: 65%

“…Hardness directly benefits wear, which is critical for coating life (or endurance) in many applications, including space missions where coatings must function for many years without replacement. Some papers that report improved hardness also observe that dopants can increase the elastic modulus of the coating [193][194][195]. However, increased hardness is not the only mechanism available, and it has been shown that some dopants decrease hardness yet improve performance [190].…”

Section: Tribological Properties Of Doped Mos2mentioning

confidence: 99%

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Solid Lubrication with MoS2: A Review

et al. 2019

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Molybdenum disulfide (MoS2) is one of the most broadly utilized solid lubricants with a wide range of applications, including but not limited to those in the aerospace/space industry. Here we present a focused review of solid lubrication with MoS2 by highlighting its structure, synthesis, applications and the fundamental mechanisms underlying its lubricative properties, together with a discussion of their environmental and temperature dependence. An effort is made to cover the main theoretical and experimental studies that constitute milestones in our scientific understanding. The review also includes an extensive overview of the structure and tribological properties of doped MoS2, followed by a discussion of potential future research directions.MoS2 belongs to the family of layered two-dimensional transitional metal dichalcogenides (TMDs). Like graphite and hexagonal boron nitride, its crystal structure consists of covalently bonded sheets, which form stacks that are held together only by weak Van der Waals interactions [16]. It occurs naturally as the mineral molybdenite, an important Mo ore. Due to the strong bonding inplane and weak bonding out-of-plane, mechanical and other properties are highly anisotropic [17], and the stacks can be easily sheared. Single-layer or few-layer (i.e. 2D) MoS2 (analogous to graphene) can be produced and studied individually [18].MoS2 has several different possible structures (polytypes), depending on the bonding within the sheets and the stacks of the sheets. While graphite has a single plane of atoms per sheet, in MoS2 each sheet consists a plane of Mo atoms sandwiched between two planes of S atoms. The single-sheet structure can feature trigonal prismatic coordination around Mo, which is the semiconducting 1H ("hexagonal") structure, or octahedral bonding, which is the metallic 1T ("trigonal") phase. 1H and the ideal 1T each have 3 atoms (MoS2) per unit cell ( Figure 1); however, theoretical calculations with density-functional theory (DFT)[19] and X-ray diffraction (XRD) experiments [20] have shown that in fact 1T is unstable with respect to distortions. The most commonly reported structure is a 3× 3 distortion that triples the unit cell, known as the 1T′ phase [21].Each single-sheet structure can be stacked into a crystal where the next sheet is exactly above the preceding one (AA stacking), producing the 1H, 1T, and 1T′ polytypes. The naturally occurring polytypes in molybdenite, however, are only based on the 1H sheet, and show more complicated stacking [9]. The more common is the 2H structure with 2 sheets per cell in AB stacking, where an S atom in one layer is above an Mo atom in the layer below [22,23]. The less common 3R ("rhombohedral") structure has 3 sheets per cell with ABC stacking [22,24]. These structures are shown in Figure 1. Mo-S bond lengths are around 2.4 Å for all polytypes [25]. DFT calculations show only very small energy differences between the 2H and 3R phases [25]. This insensitivity to stacking, and the low surface energy for 2H-MoS2 of 47 mJ/m 2 =...

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Section: Tribological Properties Of Doped Mos2mentioning

confidence: 65%

Section: Tribological Properties Of Doped Mos2mentioning

confidence: 99%

Solid Lubrication with MoS2: A Review

et al. 2019

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“…peaks located at 232.0 and 228.5 eV could be inferred as the Mo3d3/2 orbital peak in the Mo-S hybrid bond structure in MoS2 that characterized Mo 4+ in MoS2. The two weak peaks at 223.46 and 232.95 eV could be attributed to the S2s orbital and Mo-O hybrid bond structure that indicated the formation of sulfide and partial oxidation on the film surface [23]. However, the Mo-S hybrid bond of the Mo3d orbital peak of pure MoS2 was located at the binding energies of 228.4 and 231.5 eV.…”

Section: Resultsmentioning

confidence: 96%

“…As a typical transition metal sulfide, MoS 2 has a S-Mo-S sandwich structure combined by the van der Waals force [14,15]. Given its unique structure and photoelectric properties, MoS 2 has attracted considerable attention from scholars [16,17] and has been widely investigated for thin film transistors [18,19], photodetectors [20,21], and solid lubrication [22,23]. Owing to its adjustable band gap, MoS 2 can be combined with…”

Section: Introductionmentioning

confidence: 99%

Preparation of Cu3N/MoS2 Heterojunction through Magnetron Sputtering and Investigation of Its Structure and Optical Performance

et al. 2020

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Cu3N/MoS2 heterojunction was prepared through magnetron sputtering, and its optical band gap was investigated. Results showed that the prepared Cu3N/MoS2 heterojunction had a clear surface heterojunction structure, uniform surface grains, and no evident cracks. The optical band gap (1.98 eV) of Cu3N/MoS2 heterojunction was obtained by analyzing the ultraviolet-visible transmission spectrum. The valence and conduction band offsets of Cu3N/MoS2 heterojunction were 1.42 and 0.82 eV, respectively. The Cu3N film and multilayer MoS2 formed a type-II heterojunction. After the two materials adhered to form the heterojunction, the interface electrons flowed from MoS2 to Cu3N because the latter had higher Fermi level than the former. This behavior caused the formation of additional electrons in the Cu3N and MoS2 layers and the change in optical band gap, which was conducive to the charge separation of electrons in MoS2 or MoS2 holes. The prepared Cu3N/MoS2 heterojunction has potential application in various high-performance photoelectric devices, such as photocatalysts and photodetectors.

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“…Among them, there are few reports on Cu 3 N and MoS 2 composite films. MoS 2 is a typical layered 2D material, in which Mo and S are covalently bonded, and layers are connected by van der Waals force [42][43][44][45]. As the number of layers increases, the band gap also varies, and the band gap width gradually changes from 1.29 eV to 1.80 eV [43,[46][47][48][49].…”

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confidence: 99%

Photocatalytic Properties of Copper Nitride/Molybdenum Disulfide Composite Films Prepared by Magnetron Sputtering

et al. 2020

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Cu3N/MoS2 composite films were prepared by magnetron sputtering under different preparation parameter, and their photocatalytic properties were investigated. Results showed that the composite films surface was uniform and had no evident cracks. When the sputtering power of MoS2 increased from 2 W to 8 W, the photocatalytic performance of the composite films showed a trend of increasing first and then decreasing. Among these films, the composite films with MoS2 sputtering power of 4 W showed the best photocatalytic degradation performance. The photocatalytic degradation rate of methyl orange at 30 min was 98.3%, because the MoS2 crystal in the films preferentially grew over the Cu3N crystal, thereby affecting the growth of the Cu3N crystal. The crystallinity of the copper nitride also increased. During photocatalytic degradation, the proper amount of MoS2 reduced the band gap of Cu3N, and the photogenerated electron hole pairs were easily separated. Thus, the films produces additional photogenerated electrons and promotes the degradation reaction of the composite films on methyl orange solution.

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Exploring the Tribophysics and Tribochemistry of MoS2 by Sliding MoS2/Ti Composite Coating Under Different Humidity

Cited by 41 publications

References 39 publications

Solid Lubrication with MoS2: A Review

Solid Lubrication with MoS2: A Review

Preparation of Cu3N/MoS2 Heterojunction through Magnetron Sputtering and Investigation of Its Structure and Optical Performance

Photocatalytic Properties of Copper Nitride/Molybdenum Disulfide Composite Films Prepared by Magnetron Sputtering

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