Chromium Nitride Research Articles

Wear penalty for steel rubbing against hard coatings in reactive lubricants due to tribochemical interactions

Hard coatings and surface adsorptive/reactive lubricants are two common strategies for improving wear protection, but what if they are used together? In this study, steel-steel and steel-coating sliding was investigated in boundary lubrication of polar and non-polar oils containing a ZDDP or an ionic liquid. Two hard coatings, diamond-like-carbon (DLC) and chromium nitride (CrN), were used. For a steel-steel contact, wear was effectively reduced by using a more surface reactive lubricant, as expected. However, the steel ball wear was increased against a hard coating and further worsened with a more polar oil and/or a more surface reactive additive. The wear mechanism is proposed as a combined effect of physicochemical interactions with the lubricant, mechanical polishing by the counterface, and material adhesion.

Performance of diamond-like carbon coatings (produced by the innovative Ne-HiPIMS technology) under different lubrication regimes

Piston rings (PR) are responsible for over 24% of the friction losses in internal combustion engines. To minimize the friction losses and improve the life span of PR it was tested a new developed variation of the diamond like carbon (DLC), in this case, deposited on a plasma atmosphere of Argon and Neon with high power impulse magnetron sputtering (HiPIMS) power supply at P = 0,8 Pa and with a bias of −80 V. These coatings were compared with the widely used Chromium nitride (CrN) and DLCs deposited in pure Argon atmosphere. The tribology tests were performed on a block-on-ring setup with counter-body, loads, velocities and lubrication that represented the real conditions of the PR. The analyses of the results were performed using the stribeck curves where it was observed an improvement of 15.7% in friction losses of the DLC deposited with 25% of Ne in the discharge gas when compared with CrNs at the mixed lubricated regime. As well as an improvement on wear resistance on boundary regime. The wear tests were analyzed with profilometry and wear track optical microscope images.

Investigation of wear on the upper edges of webs of thin-film coated single-screw extruders processing pure polymers

Abstract During polymer extrusion there are a variety of situations in which the screwthread of the extrusion screw has an unlubricated metal-to-metal contact with the barrel wall. At the same time the screw coating is subjected to the highest loads. The combination of a secondary hardening cold work steel 1.2379 and a chromium nitride coating deposited by ARC-PVD, which is frequently used in polymer processing, is characterized and investigated. The characterization is done by metallographic examination, SEM and CLSM. The tests were performed on a pin-on-disk and a pin-roll test rig. Different roughness levels were tested on the pin-on-disk test, where massive differences in wear behavior were found. A hybrid surface structure is proposed to optimize the tribosystem. On the pin-on-disk test stand, rollers made of the same material pairing were tested. The test speed was varied to highlight differences and similarities between the tribological systems. A wear minimization of 50 % was achieved and the similarities between the tribological systems were highlighted. In addition, the investigations led to the development of a new model thesis which provides a reason for the development of stippling on the screw when processing polycarbonate.

Corrosion Resistance of Ferritic Stainless Steel X12Cr13 After Application of Low-Temperature and High-Temperature Plasma Nitriding

The impact of plasma nitriding process on corrosion resistance of ferritic stainless steel (FSS) was evaluated in this study. The FSS X12Cr13 (AISI 410) was subjected to low-temperature plasma nitriding (LTPN) treatment at a temperature of 400°C in 3H2:1N2 (l/h) and in 1H2:3N2 (l/h) reverse working atmosphere (LTPN-R) and to high-temperature plasma nitriding (HTPN) treatment at 550 °C for 15 h. The microstructure and microhardness of the untreated and nitrided stainless steel were evaluated. The corrosion properties of the untreated and plasma nitrided steel samples were evaluated using the anodic potentiodynamic polarization tests in neutral 2.5% NaCl deaerated solution. The phase analysis showed that LTPN and LTPN-R treatment on the AISI 410 steel led to the formation of N layer (nitrogen expanded ferrite) accompanied by Fe3C and Fe4N iron nitrides and CrN. The HTPN technique led additionally to the formation of an increased volume of Cr4N4 chromium nitrides and Cr15Fe7C6 chromium iron carbide. The plasma nitriding process significantly increased the microhardness of the ferritic stainless steel. The pitting was evaluated, and the pitting coefficient was calculated. The electrochemical corrosion tests showed the best corrosion resistance of the untreated X12Cr13 stainless steel, only slightly increased corrosion rates of LTPN and LTPN-R techniques, and extreme corrosion rates after application of the HTPN technique, causing Cr depletion and thereby suppressing the ability to passivation.

Effects of nitrogen element on microstructure and pitting corrosion resistance of duplex stainless steel welded joints

The microstructure, element distribution and pitting corrosion resistance of Gas Tungsten arc welding (GTAW) duplex stainless steel welded joints under 100% argon (Ar) and 98% Ar + 2% nitrogen (N2) shielding gas were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electrochemical corrosion methods. These results show that the addition of N2 to the shielding gas promotes the formation of austenite (γ) phase in the weld joint. Also, the austenite phase distribution is dendritic and the ferrite (δ) and austenite phases in the heat-affected zone are no longer banded structures. Moreover, the austenite phase in the welded joint is enriched in nickel (Ni) and nitrogen (N) elements, while the ferrite phase is enriched in chromium (Cr) and molybdenum (Mo) elements. The pitting corrosion index (PREN) of the austenite/ferrite (δ/α) phase boundary is lower than that of δ and γ phases, which leads to their preferential corrosion. The appearance of chromium nitride (Cr2N) decreases the corrosion resistance of the weld seam and the heat affected zone. N2 in the 98% Ar + 2% N2 shielding gas can restrain Cr2N precipitation, increase the pitting corrosion index of secondary austenite structure (γ 2), and improve the pitting corrosion resistance of welded joints.

CrN-Encapsulated Hollow Cr-N-C Capsules Boosting Oxygen Reduction Catalysis in PEMFC

Understanding the origin of the catalytic activity for the development of efficient catalysts is critical yet challenging. Herein, we report a simple strategy for the synthesis of chromium nitride ...

Sputtered chromium nitride/carbon nanotubes hybrid structure for electrochemical capacitors

Hybrid materials based on transition metal nitrides and carbon nanostructures are attracting intention for high-performance electrochemical energy storage systems. In this work, vertically aligned carbon nanotubes (CNTs) were grown over silicon substrate, followed by direct current plasma-sputtered deposition of chromium nitride (CrN) for different deposition times. The CNTs@ CrN electrodes exhibit vertically aligned cauliflower morphology with different degrees of dispersion on the substrate and were tested as electrodes for electrochemical capacitors (ECs). The areal capacitance of the CNTs@ CrN, as measured in 0.5 M H2SO4 electrolyte, was as high as 156.4 mF cm−2 at a scan rate of 5 mV s−1 with an excellent electrochemical retention of 90% over 10,000 cycles. Furthermore, the areal capacitance was found to increase with CrN thickness increase over the CNTs. This work demonstrates the beneficial use of CNT as template for transition metal nitride deposition and highlights CrN as a promising competitor to other transition metal nitrides already reported for ECs with similar structural morphology.

Study of Power Effect on Structural, Mechanical Properties and Corrosion Behavior of CrN thin Films Deposited by Magnetron Sputtering

Deposition of chromium nitride (CrN) thin films on Si(100) and low carbon steel (LCS) substrates has been performed using DC magnetron sputtering technique at different values of power from 100 to 150 W. A methodical study of the influence of power on structural and physical properties of the thin films was effected out. Films structure have been investigated by X-ray Diffraction (XRD) and the grain size decreased with increasing the power. Scanning Electron Microscope (SEM) used to define the thickness, where the thickness increased with the increasing of power. The surface morphology was characterized by Atomic Force Microscope (AFM) as well as by optical microscope for CrN thin films. This work shows that the residual stresses of these films, created from process, increased with the increasing of power. The corrosion examinations were presented by potentiodynamic method, Tafel curves, and electrochemical impedance spectroscopy at water solution. The best corrosion resistance characteristics are exhibited by CrN films at 150 W, having the smallest grain size.

Corrosion Resistant CrNX Nanolayers Obtained by Low Temperature Ion Nitriding of Hard Chromium Coated AISI 1045 Steel

Chromium nitrides CrXN have attracted research interest due to their excellent wear and corrosion properties when are deposited on steels. Nevertheless, due to the considerable difference between CrXN and steel expansion coefficients, microcracks and delamination are still persistent problems. In this regard, this research addressed the generation of CrNX nanolayers, through an ion nitriding process, carried out on hard chromium coated AISI 1045 steel. The effect of nitriding temperature (500°C-550°C) and nitrogen content in plasma (25, 50, and 75%) on corrosion performance and layer characteristics were studied. Grazing Incidence X-ray Diffraction analysis revealed that modified surfaces are composed of nanolayers, constituted by a mixture of CrN, Cr2N, Cr, and Fe4N. Rietveld quantification shows that the fraction of chromium nitrides in the region analyzed increased with increasing both temperature and nitrogen content in plasma, resulting CrN as the predominant phase for all evaluated conditions. The electrochemical behavior of the modified nanolayers was studied by potentiodynamic polarization technique, revealing an enhancement in corrosion performance of chromium coated 1045 steel by the nitriding treatment, showing a corrosion current density 10 times lower than the untreated sample and more positive corrosion potentials for the nitrided samples concerning chromium coated 1045 steel.

Pump elements recondition by electrolytic chromium plating

Improving the efficiency of maintenance production in agriculture closely connected to the creation and implementation of such methods of repair and recondition of elements that improve the physicomechanical and service properties of wear joint assemblies.The presence of a nitrided case on the surface of elements lays the groundwork for obtaining a complex covering based on chromium nitrides. Electrolytic chromium plating is one of the ways to recondition elements that increase the service life and machines reliability, and reduce maintenance cost. However, the widespread adoption of chromium plating for the recondition of worn elements is hold back by the low productivity of the process. Therefore, the intensification of chromium plating in reconditioning worn-out machine elements is an urgent problem. It is advisable to recondition critical parts subjecting to abrasive wear, for example, precision vapors of fuel injection equipment, with chromium plating. However, the low productivity and high-energy consumption of the process require the improvement of the electrolyte in order to increase the current output of chromium and the permissible cathode density. The article describes a method for improving the quality of an electrolyte, a method for increasing its versatility, namely the supplementation of various organic additives and complexing substances into it.

ОСОБЕННОСТИ СТРУКТУРНО-ФАЗОВЫХ ПРЕВРАЩЕНИЙ И УПРОЧНЕНИЯ ПРИ ДЕФОРМАЦИИ СДВИГОМ ПОД ДАВЛЕНИЕМ ВЫСОКОАЗОТИСТОЙ СТАЛИ С АУСТЕНИТНО-ФЕРРИТНОЙ СТРУКТУРОЙ МЕТАЛЛИЧЕСКОЙ МАТРИЦЫ

The increased anticorrosive, strength, tribological, and physical characteristics are the specific features of steels with high nitrogen content. Searching for the ways to strengthen high-nitrogen steels is a promising area of contemporary metal science. Heat treatment is one of the methods of hardening nitrogen steels as a result of precipitation hardening with nitride particles. The authors studied the influence of short-term high-temperature aging and large plastic deformations implemented by shear under the pressure of 8 GPa (SP method) on Bridgman anvils (three revolutions of anvils with the rotation velocity of 0.3 rev/min) at room temperature on the structural-phase transformations and micromechanical properties of the 08H22GA1.24 high-nitrogen steel with the mixed γ (austenite) +  (ferrite) metal matrix structure. The study identified that aging (0.5 h) at the temperature of 650 °С of steel quenched at the temperature from 1180 °С causes the formation of the mixed austenitic-ferritic structure of metal matrix in the ratio of 50 vol. % of  and 50 vol. % of α and the release of extended secondary Cr2N chromium nitrides, together with ferrite interlayers forming the areas with the pearlite-like structure. These areas cause the increased microhardness of steel with the austenitic-ferritic matrix structure (385±8 HV 0.025) compared to one of steel aged at the temperature of 550 °С (0.5 h) and having an austenitic matrix structure strengthened with secondary CrN nitrides (364±8 HV 0.025). The SP deformation of steel aged at the temperature of 650 °С (0.5 h) with the initial ++Cr2N structure leads to →ʹ transformation and the formation of submicro- and nanocrystalline structures. It causes the effective strength improvement of steel (up to 900±29 HV 0.025) and the growth of resistance to elastoplastic deformation compared to aged at the temperature of 550 °C (0.5 h) condition.

Mechanistic study on nitrogen-doped graphitic carbon-reinforced chromium nitride as a durable electrocatalyst for oxygen reduction

An ammonia-free strategy to synthesize CrN supported on N-doped carbon (CrN@NG) as an oxygen reduction (ORR) catalyst over a wide pH range is demonstrated. A synergy between the NG support and anti-corrosive CrN boosts the catalyst activity and durability.

Study of the structure and phase composition of ion-plasma coatings

The method of applying plasma coatings by the vacuum arc method is widespread in the practice of enterprises in order to increase the reliability and durability, as well as to restore machine parts and structures. The considered method is distinguished by good adhesion of the applied material to the substrate, high speed of coating deposition. Plasma coatings are characterized by the occurrence of significant residual stresses, the magnitude and sign of which depend on the technological parameters of coating deposition. At present, there are no fundamental studies of the stress state for plasma coatings of complex composition, which makes it difficult to obtain coatings with a given structure and properties. To solve this problem by X-ray diffraction analysis, the phase composition, texture and stress state in coatings based on Ti-N, Cr-N, Ti-Cr-N systems obtained by plasma deposition were studied, the thickness of which varied depending on the deposition time (5- 15 minutes). When identifying the structure, surveys were carried out in a certain range of angles. The revealed phases (TiN, Cr2N) exhibit texture and significant compressive stresses reaching ~ 3 GPa. The factors influencing the level of residual stresses are discussed, and a model of the formation of a stressed state in titanium and chromium nitride coatings is proposed. It was found that the development of the structure of the films, the substructure of grains and their preferential orientation, as well as the stress state, are interrelated and determined by the specific technological parameters of coating.

Structural and phase composition features of titanium and chromium nitride coatings obtained by ion-plasma deposition

Structural and phase composition features of titanium and chromium nitride coatings obtained by ion-plasma deposition

Early Failures of Total Knee Patients with Nickel Allergies Secondary to Carbon Fiber Debris

Aim: Currently, there are not many studies on the long-term outcomes of the specific implants used in patients with metal hypersensitivities. The purpose of this study is to report a significant number of TKA revision failures with the CFR-PEEK prosthetic knee implant with an anatomic hinge. Background: Patients can experience multiple issues following a primary Total Knee Arthroplasty (TKA). A growing body of research is finding a correlation between primary TKA failure and metal hypersensitivity, most commonly with nickel and cobalt. Because of this, knee prosthetics are being made from hypoallergenic metals, such as zirconium nitride (ZrN), to minimize the number of failures due to metal allergy. Given the relatively new development of the hypoallergenic prostheses, there is sparse data about their overall success. Objective: The purpose of this study is to report a significant number of TKA revision failures with the CFR-PEEK prosthetic knee implant with an anatomic hinge. Methods: In this study, we analyzed the sequelae of 84 patients between May 2015 to June 2020 who received a total knee revision due to a failed primary TKA with metal hypersensitivity. These patients were revised with the rotating anatomic hinge knee system, which consisted of Carbon Fiber Reinforced Poly-Ether-Ether-Ketone (CFR-PEEK implant) coated with a ZrN, Zirconium, and Chrome Nitride multi-layer surface coating with 30% polyacrylonitrile fiber content. The patients requiring an additional revision operation presented with increasing pain that showed evidence of osteolysis on plain radiographs, CT imaging, positive indium labeled WBC scans and increased uptake on bone scan. Intraoperatively, an open incisional biopsy of the surgical bed was obtained, followed by radical debridement and implantation of porex knee prosthesis. In addition, intraoperative findings included black debris that grossly stained the surrounding synovial tissue black, indicative of wear and debris from carbon fiber bearings and the anatomic hinge. Histology of the intraoperative biopsy showed the accumulation of black debris in the histiocyte, fibrosis, and perivascular cuffing of lymphocytes and multinucleated giant cells stained with black debris. Results: Of the 84 patients, 22 failed, requiring an additional revision procedure, equating to a 26 percent failure rate of the CFR-PEEK implant, averaging 25 months to failure. Conclusion: This study was meant to report the extremely high failure rate of the anatomic hinge secondary to carbon fiber debris. Perhaps carbon fiber-laden implants are not as good an option for total knee revision prosthesis because of the high failure rate compared to those with polyethylene in their hinge mechanism.

Optical Grating Techniques for MEMS-Based Spectrometer—A Review

This paper examined the innovations of the spectrometers for the measurement of consistency based parameters of the handheld Micro Electronic Mechanical System (MEMS) Spectrometer. Fast, highly sensitive, miniature spectroscopy techniques empowered quick, savvy and effective measures for various applications. In the light spectroscopy-based identification and quantification, advances in the field of wavelength discrimination are significant and essential. The identification of grid parameters and limiting conditions are necessary for the design and fabrication of diffraction gratings, for the spectrometer. This work evaluates the emerging trends in Micro-Spectrometer's Grating Techniques, focusing on the aspects of grating parameters and the recent developments of grating. The main parameters for evaluating the performance of a grating have been reviewed and found that grating efficiency, groove density, free spectral range and resolving power play a significant part in the grating performance. The fabrication technique employed as well as the materials used in the fabrication process, play a significant role in the efficiency of the grating. Silicon, Silicon dioxide (SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), Glass (Silica glass), Poly methyl methacrylate (PMMA), Chromium and Silicon nitride(Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) are the most used materials. The integration of new materials that are ideal for the state-of-the-art semiconductor industry techniques for MEMS fabrication along with a new blazing structure would increase the efficiency of the grating.

Mechanical and tribological assessment of composite AlCrN or a-C:Ag-based thin films for implant application

The present study focuses on the comparison of cathodic arc deposited AlCrN (ternary coating) and Ag alloyed a-C (amorphous carbon base coating) on chrome nitride (CrN) medical grade 316 LVM stainless steel. The work comprises of morphological, structural, nanomechanical and tribological evaluation in physiological simulated body fluid (SBF) lubrication following conditions pertaining to simulated hip joint. According to the findings, H/E, H3/E2 and Ecoating/Esubstrate significantly effect the nanomechanical and tribological properties of the coatings. While a-C:Ag/CrN exhibited better Ly value compared to AlCrN/CrN due to better surface quality, the later has shown higher Lc2 value during nanoscratch test attributed to lower H3/E2 and higher plastic work done. Inspite of lower friction coefficient, a-C:Ag/CrN observed higher wear rate during simulated tribotest attributed to low hardness, separate graphitic structure due to Ag doping and sudden increase of friction coefficient ascribed to severe abrasive delamination of a-C:Ag top layer. The wear mechanism observed under SEM microscopy indicate severe adhesion of Ti6Al4V counterbody on AlCrN/CrN coated surface. The size of wear debris obtained with AlCrN/CrN-Ti6Al4V tribopair was larger in size compared to a-C:Ag/CrN-Ti6Al4V tribopair. Nevertheless, despite inferior surface quality and lower Ly value and larger wear debris size, AlCrN/CrN coating performed better in nanoscratch (at Lc2 value) and demonstrated lower wear in simulated tribotest in physiological SBF condition.

Improvement of pitting corrosion resistance of wire arc additive manufactured duplex stainless steel through post-manufacturing heat-treatment

In this work, the unbalanced phase ratio and the adverse secondary austenite generally discovered in the wire arc additive manufactured duplex stainless steel were modified using post-manufacturing heat-treatment. The pitting corrosion resistance was significantly improved, which could be comparable to the hot-rolled 2205 duplex stainless steel after the heat-treatment at 1300 °C for an hour. The crystalline and microstructural investigation revealed that the striking corrosion resistance of the 1300 °C heat-treated sample was the result of the balanced phase ratio, the non-existence of chromium nitride, the 〈111〉//X texture of austenite, the decrease of crystalline defect density and the recrystallization of austenite.

Sputtered chromium nitride films with finely tuned intra- and intercolumnar porosities as pseudocapacitive electrode for supercapacitors

The thin-film electrode for supercapacitors has broad prospects for providing high energy storage capacity. However, the microstructure of dense film resulting in poor ion access limits its capacitance still far below the theoretical value. Here, CrN thin film electrodes with good cycle performance can be prepared by tuning the porosity of the film at the nanoscale level. The atomic diffusion process and atomic peening effect that occur during the sputtering process of chromium nitride are the pivotal parameters for generating porosity and high specific surface area. During the controlled sputtering process, an increase in the nitrogen flow rate causes an increase in the porosity in each column (intracolumnar porosity), while an increase in temperature controlling the gap between two columns (intercolumnar porosity). When the nitrogen flow rate is 10 sccm and the deposition temperature is 250 °C the CrN film has the areal capacitance of 41.7 mF cm−2, 10 mV s−1 at the thickness of 950 nm. In addition, the CrN film has good electrochemical cycling stability, the capacity retention rate is still as high as 93.2% after 20,000 cycles. Therefore, the CrN film electrode has a promising application prospects in energy storage systems such as supercapacitors.

BIND (II), characterization of die wall surface modifications for good manufacturing using the surface replication method

Die wall surface modifications are used in pharmaceutical manufacturing; however, selection of the optimal surface modification remains challenging because of a lack of analytical tools. The present study was undertaken to characterize the binding properties of pharmaceutics on die walls with various surface modifications using a new analytical tool: Binding Identification for Net Detriment (BIND). The surface modifications of die walls with and without tapering treatment examined were (i) hard chrome plating (HCr), (ii) chromium nitride coating (CrN), and (iii) mirror subsurface treatment and CrN-coating (CTOP/CrN). Losartan potassium (LP) was chosen as the model chemical. BIND was employed to clarify the influence of surface modification of the die wall on the binding characteristics of the highly-adhesive LP formulation. Use of the die without any modification led to poor tableting properties, as evidenced by a 60.4% powder adhesion density. Surface modifications of the die wall resulted in significant attenuation of binding, reducing the powder adhesion density to 16.6% (HCr), 13.9% (CrN), and 10.8% (CTOP/CrN). Tapering treatment successfully reduced the powder adhesion by 2.9–5.8%. Surface-polishing with HCr made no significant difference to powder adhesion, whereas differences were observed for CrN. Thus, the BIND results suggested that the combined use of CTOP/CrN and tapering treatment is effective for stable production. In this first attempt, BIND can be available for analyzing the effects of die wall surface modifications on the binding characteristics.