I. V. Blinkov

Properties of nanostructured TiN-Ni ceramic-metal coatings obtained by ion-plasma vacuum-arc method

Physicomechanical and tribological properties of TiN-Ni ceramic-metal coatings prepared by ion-plasma vacuum-arc deposition are investigated. It is established that the hardness (H) increases from 23 to 54 GPa with the Ni content from 0 to 12 at %, which is determined by the influence of the nanostructured nitride component of coatings. Coefficients HE−1 and H3E−2, which characterize the material resistance against the elastic and plastic failure deformation, reach 0.104 and 0.567 GPa, respectively. The further increase in the nickel concentration in coatings to 26 at % leads to a decrease in H to 23–25 GPa, which is associated with the influence of the increasing amount of soft plastic metal and the formation of noticeable porosity in the bulk of coatings. The friction coefficient of studied coatings is 0.45, against 0.58 (for the TiN coating) and 0.72 (for the hard-alloy base). The cohesion failure mechanism of TiN-Ni nanostructured coatings (CNi = 2.8–12 at %) is established, and critical loads which characterize the appearance of the first crack (13.5–14.2 N) and the local coating attrition up to the substrate (61.9–64.4 N) are determined. The complete attrition of coatings does not occur up to a load of 90 N, which points to their high adhesion strength. The developed nanostructured ceramic-metal coatings are characterized by high heat resistance up to 800°C.

Influence of deposition parameters of the Ti-Al-N/Zr-Nb-N-Cr-N multilayered nanostructured coating obtained by the arc-PVD method on their physicomechanical, tribological, and operational properties

Physicomechanical, tribological, and operational properties of the Ti-Al-N/Zr-Nb-N-Cr-N multilayered coatings obtained by the arc-PVD method are investigated. Dependences between the controlled deposition parameters (the bias potential across the substrate and the revolution rate of the sample relative to sputtered cathodes) and the characteristics of the coatings having hardness up to 37 GPa and adhesion strength of over 100 N are established. Comparative investigations into the tribological properties of multilayered coatings of various compositions showed that the developed coatings are characteristic of the lowest friction factor. A cutting tool with such coatings possesses high resistance properties in conditions of the interrupted and continuous cutting of gray cast iron (SCh30) and steels (St. 45, X18H10T).

Ceramic-metallic (TiN-Cu) nanostructured ion-plasma vacuum-arc coatings for cutting hard-alloy tools

The structure and properties of TiN-Cu coatings with a broad range of copper concentrations (CCu = 0.6–20 at %), which were fabricated by the ion-plasma vacuum-arc deposition on a TT10K8B hard-alloy tool, including its cutting resistant tests, were investigated. The introduction of copper into the coating composition diminishes crystallites of the nitride phase from 100 to 20 nm. The hardness of coatings increases from 20 to 40 GPa, with an increase in CCu to 7–8%. The further increase in the copper content, which is accompanied by diminishing crystallites of the nitride phase, is characterized by a decrease in hardness to 14–15 GPa, which is associated with the influence of soft plastic metal. Resistant cutting tests of steel 35KhGSA of removable multifaceted plates (RMP) with the TiN-Cu coatings indicate that the optimally selected composition (TiN-7-8 at % Cu) increases RMP resistance more than by a factor of 6 and 2.5 as compared with tools without the coating and with the TiN coating deposited according to the basic technology, respectively.

Structurization and phase formation in the course of preparing nanocomposite TiN–Ni ion-plasma vacuum–arc coatings and their thermal stability

Structure and phase formation in the course of fabricating composite ion–plasma vacuum-arc nanocrystalline TiN–Ni coatings are investigated in a broad range of nickel concentrations (from 0 to 26 at %). It is established that the introduction of Ni into the coating composition refines the nitride phase crystallites. The arithmetic mean size of TiN grains decreases from 100–120 to 15–18 nm upon varying the Ni concentration from 0 to 12 at % and normal particle-size distribution. The further increase in the Ni content is accompanied by the transition to the polymodal particle distribution with an increase in their arithmetic mean diameter to 27 nm for the third mode. Nickel in coatings at a concentration of 12–13 at % Ni is in the X-ray amorphous state. As the concentration increases above 13 at %, the TiNi intermetallic compound is formed in the composition of coatings. This phenomenon in turn causes the appearance of porosity in the structure of the deposited layer. The blocking role of nickel simultaneously weakens with the formation of the intermetallic compound, which manifests itself in the growth of separate TiN grains to 30–35 nm. The TiN–Ni coatings are characterized by the thermal stability of the structure and composition upon heating to 800°C.

The effect of deposition parameters of multilayered nanostructure Ti-Al-N/Zr-Nb-N/Cr-N coatings obtained by the arc-PVD method on their structure and composition

The structure and elemental and phase compositions of the Ti-Al-N/Zr-Nb-N/Cr-N multi-layered coatings obtained by the arc-PVD method are investigated. A three-cathode sputtering system including the Ti-Al, Zr-Nb, and Cr cathodes was used for their deposition. The controlled parameters of the process were the rotation speed of coated samples relative to sputtered cathodes, the current of the sputtering arc on the zirconium-niobium cathode, and the negative electric bias potential supplied to the substrate. These parameters varied within the limits from 1 to 3 rpm, from 135 to 170 A, and from −80 to −160 V, respectively. The possibility of forming multilayered coatings with a thickness of single layers at a level of ∼10 nm and their transfer from a multilayered structure to a single-layered one due to the variation in the deposition parameters is shown. The parametric dependences of the controlled parameters of the formation of coatings on their composition and structure components are found.

Acquisition and properties of wear-resistant PVD/CVD coatings on a hard-alloy tool

The processes of structure and phase formation during the formation of combined physical deposition (PVD)/chemical deposition (CVD) coatings on a hard-alloy tool are investigated. It is shown that the formation of the Cr PVD barrier layer prevents the formation of the η phase with the subsequent deposition of the TiC-Ti(C,N)-TiN CVD coating. Treatment of the CVD coating with the ion-plasma flow and deposition of the finishing TiN PVD layer lead to the formation of the texture {111} in the coating and the diminishment of its subgrains to ∼30 nm. Upon going from articles with CVD coatings to combined PVD-CVD-PVD coatings, the strength and hardness of hard-alloy blades increase. This is explained by the effect that the corresponding phase and structural transformations that occur in the coating and at the phase interfaces during their formation have on these characteristics. The results of certification tests of cutter tools for continuous and intermittent cutting indicate the efficiency of these coatings both for turning work and, especially, for mill operation, when high toughness, along with hardness, is the most important characteristic.

Evaluation of Thermal Stability of Multilayered Nanostructured Coatings Based on Analysis of Diffusion Mobility of Components of the Layers

The thermal stability of multilayered nanostructured coatings is evaluated by analyzing the diffusion mobility of layer components. The possibility of increasing the thermal stability of multilayered coatings based on mutually soluble Ti–Al–N and Cr–N layers due to the introduction of an additional barrier layer based on Zr–N into a multilayered nanostructure is investigated in detail. Calculated diffusivities of basic metallic elements of the coating into corresponding nitride layers upon heating in a temperature range of 800–1000°C evidence the absence of noticeable diffusion spread of layer boundaries in the presence of the Zr–N-based barrier layer. For example, their values lower upon its introduction (it is found at t = 1000°C, cm2/s: DCr/TiN = 5 × 10–17, Dcr/ZrN = 2 × 1018,

Hardness, adhesion strength, and tribological properties of adaptive nanostructured ion-plasma vacuum-arc coatings (Ti,Al)N–Mo2N

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