(Cr, N)-DLC/DLC multilayer films with different bilayer numbers and thickness ratios were prepared on cemented carbides and silicon wafers by cathodic vacuum arc technology. Surface and cross-section ...morphologies of multilayer films were observed by scanning electron microscope. Roughness, hardness, adhesion strength, friction coefficient and wear rates of the deposited films were investigated by surface profiler, nanoindentor, scratch tester, and ball-on-disk tribometer, respectively. Alternating stress field from adjacent sublayers benefited the mechanical properties while macroparticles piercing through interfaces between sublayers provided passages for cracks propagation and deteriorated films' mechanical properties. As bilayer numbers varied from 10 to 20 average friction coefficient and roughness of multilayer films had the same changing trend and wear rates increased linearly from 2.45 × 10−7 mm3/Nm to 3.81 × 10−7 mm3/Nm. Improving proportion of (Cr, N)-DLC layer in multilayer films increased quantity of macroparticles, leading to the rise of multilayer films' roughness, average friction coefficient and wear rates.
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•(Cr, N)-DLC/DLC multilayer films with different structure were prepared.•Surface roughness varied as film structure changed.•Macroparticles in (Cr, N)-DLC/DLC multilayer film affect film properties greatly.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
TiAINCu nanocomposite coatings with Cu concentration of 0-1.4 at.% were deposited on the high- speed steel （HSS） substrates by filtered cathodic arc ion plating technique. The chemical composition, ...microstructure, morphology, adhesion strength, mechanical and tribological properties of the TiAIN/Cu coatings were characterized and analyzed. The results reveal that the coating structure and properties depend on not only the Cu concentration, hut also the deposition condition. The addition of Cu significantly decreases the grain size and weakens the texture in the TiAlN/Cu coatings. With increasing the Cu concentration, the coating hardness decreases slightly from 30.7 GPa of the pure TiAlN coating to 28.5 GPa of the TiAlN/Cu coating with 1.4 at,% Cu. All the TiAlN/Cu coatings present sufficient adhesion strength. In addition, the existing state of additive Cu in the TiAlN/Cu coatings is also investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Cr-Mo-N films were deposited on high speed steel（HSS） substrates by a DC reactive magnetron sputtering equipment coupled with two horizontal magnetron sources.The effects of substrate negative ...bias voltage（Vb）,substrate temperature（Ts） and gas flow ratio（R= N2/（N2+ Ar）） on the microstructure,morphology,as well as the mechanical and tribological properties of the Cr-Mo-N films were investigated by virtue of X-ray diffraction（XRD） analysis,X-ray photoelectron spectroscopy（XPS）,field emission scanning electron microscopy（FESEM）,atomic force microscopy（AFM）,nano-indentation test,ball-on-disk tribometer,and Rockwell indenter et al.With increasing Vbto-100 V,the preferred orientation of the films changed from（111） to（200） and their mechanical and tribological properties were improved gradually,too.It was also found that Tsgave a significant effect on mechanical property enhancement.When the Tsreached 300 ℃,the film obtained the highest hardness and effective elastic modulus of approximately 30.1 and 420.5 GPa,respectively and its critical load increased to about 54 N.With increasing R,the phase transformation from body-centered-cubic（bcc） Cr and hexagonal CrMoNxmultiphase to single face-centered-cubic（fcc） solid solution phase was observed.The correlations between values of hardness（H）,effective elastic modulus（E*）,HIE*,H3/E*2,elastic recovery（1/14） and tribological properties of the films were also investigated.The results showed that the elastic recovery played an important role in the tribological behavior.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•WB2/a-WBC multilayer films with different thick modulation periods are prepared.•WB2 films and WB2 layers grow preferentially along (101) and (001) plane, respectively.•Both lattice distortion by ...C-doping and stress release by a-C control the film stress.•Decreasing the bilayer period causes an increase in both hardness and wear rate.•The wear mechanism of the WB2/a-WBC films is a mixture of abrasion and lubrication.
WB2/a-WBC multilayer films with different modulation periods ranging from 145 to 830 nm were synthesized by direct-current magnetron sputtering. The effect of modulation period (Λ) on structure and tribo-mechanical properties of the WB2/a-WBC multilayer films was studied. The WB2 monolayer grows preferentially along (101) plane. However, the multilayered structure changes the growth of WB2 sublayers to (001) plane, and a transition layer with composition gradient distribution is formed at the interface between the two sublayers. Consequently, WB2, WB2(C) solid solution and a-WC are detected in the WB2 sublayer, while a-WBC, a-WC and a-C are found in the WBC sublayer. As the modulation period decreases, the residual compressive stress (-384∼-827 MPa) of the WB2/a-WBC films increases first and then decreases, and the hardness of the WB2/a-WBC films (18.8∼23.7 GPa) gradually increases under the joint action of solid solution strengthening and interface strengthening. Moreover, the fracture toughness of the WB2/a-WBC films is also improved greatly resulting from the multilayered structure with the soft a-WBC sublayers. The wear mechanism of the WB2/a-WBC films is a mixture of abrasion and lubrication, and the friction coefficient and wear rate of the WB2/a-WBC films are lower than those of the WB2 and WBC monolayer films because of their excellent toughness and lubricating effect as well as moderate hardness. Comprehensively, the WB2/a-WBC films with Ʌ=830 and 415 nm display lower friction coefficient (∼0.08) and wear rate (1.14∼1.24 × 10−7 mm3/mN).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, Ni/nano-Al
2
O
3
composite coatings and the Ni/Ni–Al
2
O
3
multilayer coatings have been prepared on the 304 stainless steel substrate by adding the nano-Al
2
O
3
particle in Ni ...plating solution and by alternately brush electroplating, respectively. The microstructure, hardness and wear resistance of the composite and multilayer coatings were studied. Results showed that adding Al
2
O
3
nanoparticle in coatings significantly influences the size and growth direction of grain. The Al
2
O
3
content and hardness of coatings first increased, reached a maximum value of 603 HV and then decreased with the increase in the addition of Al
2
O
3
nanoparticle in Ni plating solution. The friction coefficient, wear loss and wear rate showed an opposite trend. In terms of mass loss and wear rate, the wear resistance of coating increases with increasing Al
2
O
3
content in coatings. An appropriate addition (20–25 g L
−1
) of Al
2
O
3
nanoparticles can effectively enhance the wear resistance of the brush electroplating Ni coating. The minimum wear rate is 2.2–2.3 10
−5
mm
3
N
−1
m
−1
. The multilayer structure coatings can prevent or delay microcrack initiation and growth by layer interface and grain boundary and increase the thickness of coatings without cracks. The multilayer coatings possessed the approximately same hardness (595 HV) and tribological properties compared with monolayer coatings.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Aluminum doped zinc oxide （AZO） thin films were prepared by DC magnetron sputtering at low substrate temperature. A coaxial solenoid coil was placed near the magnetron target to enhance the plasma ...density （Ji）. The enhanced plasma density improved significantly the bulk resistivity （p） and its homogeneity in spatial distribution of AZO films. X-ray diffraction （XRD） analysis revealed that the increased Ji had influenced the crystallinity, stress relaxation and other material properties. The AZO films deposited in low plasma density （LPD） mode showed marked variation in p （ranging from -6.5x10-2 to 1.9x10-3 Ω.cm）, whereas those deposited in high plasma density （HPD） mode showed a better homogeneity of films resistivity （ranging from ~1.3x10-3 to 3.3x10-3 ~.cm） at different substrate positions. The average visible transmittance in the wavelength range of 500-800 nm was over 80%, irrespective of the deposition conditions. The atomic force microscopy （AFM） surface morphology showed that AZO films deposited in HPD mode were smoother than that in LPD mode. The high plasma density produced by the coaxial solenoid coil improved the electrical property, surface morphology and the homogeneity in spatial distribution of AZO films deposited at low substrate temperature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
WB2/CrN multilayer films with thick modulation periods over 50 nm (Λ = 1400, 315, 235, 150, 55 nm) were synthesized by direct-current magnetron sputtering, and the influence of modulation period on ...microstructure and mechanical properties for the multilayer films was systematically studied. In WB2/CrN multilayer films, CrN sublayers present the columnar microstructure. As Λ decreases, the structure of WB2 sublayers evolves from (110) orientation to (001) orientation to amorphous structure, and critical crystalline thickness for WB2 sublayers is over 150 nm here. A transition layer, which shows the columnar crystal with size of 10–11 nm high and 2.5–3.5 nm wide caused by the effect of the crystalline interface of the CrN sublayers, is detected in WB2 sublayers. Additionally, a-BN, WB2, WB2(N), CrN, Cr2N and Cr2O3 phase are formed in the multilayer films. Moreover, film hardness mainly obeys the rule of mixture. The maximum hardness of 31.2 GPa is obtained at Λ = 315 nm due to crystalline WB2 sublayers with (001) preferred orientation, and amorphous WB2 sublayers greatly reduce the film hardness to only 22.3–24.3 GPa at Λ ≤ 235 nm. Consequently, the poor hardness leads to the higher wear rates (5.7–7.8 × 10−7 mm3/mN) of multilayer films with Λ ≤ 235 nm compared with those (2.9–3.3 × 10−7 mm3/mN) of other films. However, both the fracture toughness and adhesive strength of the films present an increasing trend with decreasing Λ, resulting from the soft CrN and BN phases and a certain amount of interface. In conclusion, decreasing the critical crystal-thickness of the WB2 sublayers, controlling the N content in WB2 sublayers and getting sharp interfaces will play important roles in developing the higher-performance WB2/CrN multilayer films.
•WB2/CrN multilayer films with different bilayer periods over 50 nm are prepared.•A transition layer with nano-columnar crystal exists between WB2 and CrN sublayers.•Critical crystalline thickness of WB2 sublayers is over 150 nm in this work.•Decreasing bilayer period to ≤235 nm causes a reduction in hardness and wear rate.•Multilayer architecture promotes the film toughness and adhesive strength.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
WB2/CrN multilayer films with thick modulation period about 500 nm but different modulation ratios (tWB2:tCrN = 1.2, 2, 3 and 4) were deposited on steel substrates by magnetron sputtering, and the ...effect of modulation ratio on the structure, residual stress and tribo-mechanical properties of the WB2/CrN multilayer films was systematically studied. Additionally, WB2 and CrN monolayer films with various thicknesses were also prepared to discuss the growth behavior and the related properties of the WB2/CrN multilayer films. All the sample films present the columnar growth, and the particle size in the WB2 monolayers is smaller than that in the corresponding WB2 sublayers. The preferred orientation of WB2 (260–400nm) and CrN monolayers (132–220 nm) is (101) and (111), respectively. However, the multilayered structure changes the orientation of CrN sublayers to (002), and crystalline Cr2N phase is detected in WB2/CrN multilayers caused by the element diffusion at interface. Moreover, the multilayered structure reduces the compressive stress of the WB2 films greatly by diffusion of point defects to interfaces and an indirect effect of interfaces on stress via film structure with soft CrN, and the residual stress of the WB2, CrN and WB2/CrN films is −2.64∼-4.16, −0.85–0.57 and −1.49∼-2.61 GPa, respectively. Furthermore, film hardness ranging from 27.9 to 33.0 GPa mainly obeys the rule of mixture. The adhesive strength drops greatly from 26 to 17 N with the increasing tWB2:tCrN, and the tensile CrN bottom-layer deteriorates the adhesive strength of the WB2/CrN multilayers with tWB2:tCrN = 2. Overall, WB2/CrN films with tWB2:tCrN = 3 show better wear resistance with lower friction coefficient ∼0.35 and wear rate about 3.6 × 10−7 mm3/mN benefiting from their higher hardness, lower roughness, proper toughness and compressive stress.
•WB2/CrN multilayer films with different modulation ratios are prepared.•The orientation of the CrN monolayer is different than that of the CrN sublayer.•Multilayered structure can release the residual stress of the WB2 films greatly.•Bottom CrN sublayers with tensile stress reduce the adhesion of WB2/CrN films.•WB2/CrN films with tWB2:tCrN = 3 and Λ ≈ 500 nm show better tribo-mechanical properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Crystalline and amorphous W–Si–B coatings with different Si contents were fabricated by magnetron sputtering. The influence of Si content on microstructure, mechanical and tribological properties of ...the coatings was evaluated. The results reveals that the crystalline W–Si–B coatings are nanocomposite structures consisting of nanocrystalline AlB2-type WB2 grains and amorphous Si/Si3N4. Crystalline coatings with Si content of 4.7 at.% exhibits the maximum hardness of 35.8 GPa and better fracture toughness compared with pure WB2 coating, leading to the lowest wear rate of 1.3 × 10−7 mm3/Nm. As for the amorphous W–Si–B coatings, the lower hardness of the coatings tends to lead to excellent fracture toughness, which gives rise to the low wear rate. The different enhancement mechanisms of both types of coatings are discussed in detail.
•Crystalline and amorphous W–Si–B coatings were deposited by magnetron sputtering.•The mechanical and tribological properties of the crystalline W–Si–B coating were improved by the doping of Si element.•The amorphous W–Si–B coatings showed better fracture toughness and excellent wear resistance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Raman spectroscopy was used to measure Raman spectra of the inner SiC fibers and surface C-rich layers of SiC fibers, composite precursors and SiCf/Ni-Cr-Al composites. The residual stresses of the ...inner SiC fibers and surface C-rich layers were calculated, and the effect of the (Al + Al2O3) diffusion barrier layer on the interfacial residual stress in the composites was analyzed in combination with the interface microstructure and energy disperse spectroscopy (EDS) elements lining maps. The results show that the existence of (Al + Al2O3) diffusion barrier improves the compatibility of the SiCf/Ni-Cr-Al interface, inhibits the adverse interfacial reaction, and relieves the residual stress inside SiC fibers and at the interface of composite material. Heat treatment can reduce the residual stress at the interface. As the heat treatment time increases, the residual stress at the interface decreases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
