Plasma Nitriding Method Research Articles

Surface Modification of Chromium–Nickel Steel by Electrolytic Plasma Nitriding Method

Electrolytic plasma nitriding is an attractive chemical heat treatment used to improve the surface properties of steel by implementing nitrogen saturation. This method is widely applied to steel and iron-based alloys operating under various operating conditions. In this work, using liquid-phase plasma nitriding technology, a nitrided layer was obtained on the surface of 40CrNi steel in electrolytes of different concentrations. The microstructure and phase composition of the nitrided layer were investigated and analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and we performed Vickers hardness and wear resistance tests using the ball-on-disc method. The microhardness and wear resistance of nitrided 40CrNi steel were significantly improved due to the lubricating properties of the ε-Fe2N phase formed on its surface.

Investigation of the Surface Properties and Wear Properties of AISI H11 Steel Treated by Auxiliary Heating Plasma Nitriding

This paper presents an auxiliary heating method to maintain a uniform specimen temperature and precisely control nitriding temperature during plasma nitriding. The surface properties and wear properties of AISI H11 steel treated by auxiliary heating plasma nitriding are investigated. Firstly, the specimens with different diffusion layers and different hardness levels are fabricated through changing the plasma nitriding temperature. Secondly, the surface properties of the plasma-nitrided H11 steel specimens are characterized by a scanning electron microscope (SEM), X-ray diffractometer, metallographic microscope and microhardness tester. The results show that the surface hardness of the plasma-nitrided specimen is almost twice as high as that of the untreated specimen. The thickness of diffusion layer increases with the increase of nitriding temperature. However, the surface hardness firstly increases and then decreases with the increase of the nitriding temperature. Finally, the wear properties of untreated and plasma-nitrided H11 steel specimens are investigated under different friction conditions. The results show that the plasma-nitriding method can significantly improve the wear resistance of AISI H11 steel. The friction coefficient fluctuations of the plasma-nitrided specimens are all lower than those of the untreated specimens. In addition, the wear rates of the plasma-nitrided specimens rise along with load, and reduce along with the sliding speed and friction temperature.

Spectroscopy study of composite coating created by a new method of active screen plasma nitriding on pure aluminum

In this study, the Active Screen Plasma Nitriding (ASPN) method was used to create a nitride layer on the aluminum Al1050. The goal of the study was to investigate the mechanism of formation of composite nitride coating (AlN/Fe2-3N) on an aluminum substrate and carry out a spectroscopic examination on this coating. For this purpose, the specimens of Al1050 were subjected to the ASPN process at temperatures of 450 and 500 °C for 5 and 10 h with constant conditions of 20%H2 + 80%N2 atmosphere, 80% duty cycle, and 10 kHz frequency. Coating characterization was performed by Grazing Incidence X-ray Diffraction (GIXRD) analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Glow-Discharge Optical Emission Spectroscopy (GDOES), and Field Emission Scanning Electron Microscopy (FE-SEM) with Energy Dispersive Spectroscopy (EDS) analysis. The results showed that the ASPN method can be used to form a composite nitride layer on an aluminum substrate. Based on the results, the paper also proposes a new mechanism for the formation of the composite layer, in which this layer is divided into two sections: a surface section made up of nitride particles and a sub-surface section consisting of diffusive layer.

Innovation Utilization of Nitridation Method in Improving Hardness and Corrosion Resistance of Blacksmiths Crafts

Hardness and corrosion resistance are properties that must be possessed by blacksmiths. One of the main problems of this small blacksmith industry is the process of finisihings handicrafts, weak mechanical properties and poor corrosion resistance making it difficult to compete for a wider market nationally and internationally. The purpose and aim of this research is to assist the blacksmith craft industry in increasing hardness and corrosion resistance so that the results of these crafts can compete at the national and international levels. The Plasma Nitriding method and the field nitriding scale by spraying Nitrogen into the results of blacksmith crafts heated under recrystallization temperatures. On the scale of nitriding the field is by spraying nitrogen as a cooling medium on the results of the blacksmith craft that has been preheated at temperatures of ± 723 to 900 ºC. The hardness level of the blacksmith craft test specimens carried out by the nitriding process increased hardness (HRC) by 17.5% and with corrosion resistance increased by 35% from the row material.

Surface Structure Evaluation of Functional Surfaces after Plasma Nitriding of Barrel Steel 42CrMo4

With increasing demands on the functional properties of machine parts, the demands on the quality of their surfaces are increasing. Any technological method used to realize the surface of functional surfaces leaves unevenness, which is essential for the function of these surfaces. The increase of the functional properties of functional surfaces can be realized by using the plasma nitriding method. However, the used diffusion technology also changes the surface structure of the components. The presented paper deals with evaluation of the change of the structure of the ground functional surfaces of barrel steel 42CrMo4 after plasma nitriding. Furthermore, the change in surface hardness and friction and wear coefficient, which have a direct effect on the functional properties, was analysed. The surface structure deteriorates and the friction coefficient is slightly increased after plasma nitriding. However, the wear coefficient reaches lower values, which, together with an increase in surface hardness, result in the use of this technology for exposed components.

Effect of Nitriding on the Microstructure and Mechanical Properties of Stainless Steels

Austenitic stainless steels are common spread in many industries. Plasma nitriding is one of the few technologies that allows surface modification of austenitic stainless steels. In this study, a plasma nitriding method to form a hard surface layer at two different austenitic steels AISI 302 and AISI 316L. The surface morphology, chemical composition and mechanical properties of the formed layers were described and the results were compared with each other. The formed nitrided layers on both steels created a uniform multi-phase layer which was characterized by high hardness and very good abrasion resistance.

Enhanced wear and corrosion resistance of AISI-304 steel by duplex cathodic cage plasma treatment

The austinite stainless steel is widely employed in several industries due to exceptional corrosion resistance. Unfortunately, their use is restricted due to low surface hardness and poor wear resistance. The aim of this work is to improve the wear and corrosion resistance of AISI-304 steel using duplex cathodic cage plasma nitriding method. The duplex treatment is carried out in a two-step process using an alternative combination of aluminium and austinite stainless steel cathodic cages, with a process duration of 1 and 4 h, respectively. The results of duplex treatment samples (first processed by an aluminium cathodic cage (pre-Al CC) and in reverse order (post-Al CC)) are compared with single aluminium, and austinite stainless steel cathodic cage treated samples. The hardness-indentation depth profile illustrates the significant improvement in hardness by post-Al CC nitrided sample, and a strong dependence on processing order is observed. The aluminium nitride is found to be leading phase in the post-Al CC sample, which is probably responsible for significant hardness improvement. Particularly for post-Al CC treated sample, the wear rate and corrosion rates are dramatically reduced by processing. This study shows that duplex treatment with a particular processing specific order is highly beneficial for mechanical, wear and corrosion properties of the sample under consideration. The use of a single processing unit for both treatments, better surface uniformity, low-processing temperature, short combined treatment time and industrial compatibility of the system suggest the suitability of the technique for industrial applications.

Evaluation of the formation of compound coatings on aluminium by the new method of active screen plasma nitriding

In this paper, a composite coating of a mixture of AlN and Fe2–3N was created on Al1050 by plasma nitriding method using an active screen. The surface of aluminium samples was nitrided under the following conditions: gas atmosphere %20H2–%80N2, at 550 °C, 80% duty cycle and the frequency of 10 kHz for 2, 5, 10 and 15 h. The coatings were characterized using grazing incidence x-ray diffraction, optical microscopy, field emission scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy and nano-hardness. The dominate phase in the active screen plasma nitriding (ASPN) of compound layer was ε: Fe2–3N and AlN, additionally with increasing processing time, the thickness of compound layer was increased. According to FE-SEM results the sample surface was covered by nano sized iron nitride particle. The compound layer thickness ranges from 4.8 0.4 μm to 12.0 1.4 for 2 h to 15 h of deposition process respectively. Moreover, the finest nitride particle size is about 124 21.3 nm in diameter for the sample operated at 550 °C for 2 h and the size of the coarsest one is about 514.4 72.2 nm in diameter belonging to the sample operated at 550 °C for 15 h. The results indicated that the samples were coated with a uniform distribution of polygonal nitride particles. This coating can improve surface properties.

Investigation of nanomechanical and adhesion behavior for AlN coating and AlN/Fe2-3N composite coatings created by Active Screen Plasma Nitriding on Al 1050

This study investigated the effect of nitriding time and temperature on the mechanical properties of the composite AlN/Fe2-3N coating deposited on the pure aluminium substrate using the novel Active Screen Plasma Nitriding (ASPN) method. ASPN treatment was performed for 2, 5, 10, 15 h at temperatures of 450,500, and 550 °C and Conventional Plasma Nitriding (CPN) treatment was carried out for 5 h at 500 °C. All treatments were performed at the 10 KHz frequency with 80% duty cycle on the Al1050 substrate under 20%H2+80%N2 atmosphere. Phase and microstructure studies were performed using, respectively, the grazing incidence x-ray diffraction (GIXRD) system and the field emission - scanning electron microscopy (FE-SEM) system equipped with energy-dispersive spectroscopy (EDS) analyzer. The mechanical strength of the coating was evaluated by the roughness, nano-hardness, nano-scratch, and adhesion strength tests performed on coated and uncoated specimens. According to the results, the uncoated Al1050 specimen, the CPN-treated specimen, and the ASPN-treated specimen had a mean nano-hardness of 0.7 ± 0.1 GPa, 10.9 ± 0.6 GPa, and 9.6 ± 0.5 GPa, respectively. It was also found that the single-phase AlN coating has a better adhesion strength and scratch strength (LC3 = 12 N) than the composite AlN/Fe2-3N coating (LC3 = 10 N). Examination of scratch mechanisms in hard AlN and AlN + Fe2-3N coatings deposited on a soft aluminium substrate showed that the failures in these coatings are due to tensile-type Hertzian cracks. However, as the load increases, the substrate undergoes increasing deformation and failures shift to chipping and interfacial spallation.

X-Ray Residual Stress in the S-Phase of Stainless Steel Nitrided by a Plasma Nitriding Method and Residual Stress Measurement of a DLC Film Deposited on the S-Phase

X-Ray Residual Stress in the S-Phase of Stainless Steel Nitrided by a Plasma Nitriding Method and Residual Stress Measurement of a DLC Film Deposited on the S-Phase

On the Erosion–Corrosion Behavior of Active Screen Plasma Nitrided St52 Steel

In this work, samples of St52 steel were plasma nitrided using an iron screen, in an N2: H2 gas mixture ratio of 4 : 1, at 500 and 550°C for 5, 10 and 15 h. The X-ray diffraction and optical microscopy methods were used for structural characterization of the coatings. Results indicated that the coatings were composed of Fe2–3N and Fe4N phases growing at longer deposition times. Moreover, the Fe2–3N phase was decomposed to Fe4N after 10 h of plasma nitriding. The erosion–corrosion behavior of nitrided coatings and a bare substrate were studied in various impact angles: 30, 45, 60 and 90 degrees. Polarization curves of the coated and uncoated samples were recorded between–900 to 600 mV, as a function of the slurry impact angle. Results showed that an active screen plasma nitriding method significantly enhanced the erosion–corrosion resistance of the St52 steel. Moreover, an impact angle of 30° on the sample surface yielded a lower weightloss whereas increasing the impact angle up to 90° caused more weight-loss due to the brittle characteristic of iron nitride coatings. According to SEM micrographs, by increasing the impact angle up to 90°, the depth of the removed mass increased substantially.

White-light emission from AlN dendrites

The AlN dendrites were prepared by high temperature plasma nitridation method. The AlN dendrites are composed of hierarchical AlN polycrystal architectures with a wide size range. The photoluminescence spectra of the AlN dendrites exhibit white-light emission including three main bands located at red, green and blue-violet. The multi-colors emission is dependent on the morphology and size diversities of the AlN dendrites. The mechanism of defect luminescent is investigated.

プラズマ窒化法によりオーステナイト系ステンレス鋼表面に形成した S 相のX線残留応力および S 相上に成膜した DLC 膜の残留応力測定

プラズマ窒化法によりオーステナイト系ステンレス鋼表面に形成した S 相のX線残留応力および S 相上に成膜した DLC 膜の残留応力測定

Structural and mechanical evaluation of deposited nano structured TiN coating using active screen plasma nitriding technique

Nano structured TiN coatings were prepared by means of active screen plasma nitriding (ASPN) method at a constant temperature of 550 °C for 5, 7.5 and 10 h under three gas mixtures of H2:N2% = 3:1, 1:1 and 1:3. In order to investigate the coating properties such as the chemical composition, surface morphology, surface topography and hardness, several analysis techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and nano indentation were employed. The results indicated that the growth of the TiN film under active screen plasma nitriding deposition had a (2 0 0) preferred orientation. Moreover, it was found that N2-50%H2 atmosphere provides the highest deposition rate leading to the maximum roughness and minimum nano hardness values. Similar observation was obtained by increasing the nitriding time. Furthermore, a model was proposed for the relation between the hardness and the surface roughness of the coating in which higher surface roughness leads to lower hardness.

Proliferation of human periodontal ligament mesenchymal cells on polished and plasma nitriding titanium surfaces

AIM: To evaluate the proliferative capacity of mesenchymal cells derived from human periodontal ligament on polished and plasma-treated titanium surfaces. METHODS: Eighteen titanium disks were polished and half of them (n=9) were submitted to plasma nitriding using the cathodic cage technique. Mesenchymal cells were isolated from periodontal ligament of impacted third molars (n=2) and cultured on titanium disks (polished and nitrided) and on a plastic surface as a positive control of cell proliferation. Cell proliferation was analyzed and growth curves were constructed for the different groups by determining the number of cells adhered to the different surfaces at 24, 48 and 72 h after plating. RESULTS: Higher cell number was observed for the nitrided surface at 24 and 48 h. However, no statistically significant difference in cell proliferation was observed between the two different surface treatments (p>0.05). CONCLUSIONS: We concluded that plasma nitriding produced surfaces that permitted the proliferation of human periodontal ligament mesenchymal cells. Associated to other physical and chemical properties, it is possible to assume the feasibility of plasma nitriding method and its positive effect on the early cellular events of osseointegration.

Optimization of the ASPN Process to Bright Nitriding of Woodworking Tools Using the Taguchi Approach

The subject of the research is optimization of the parameters of the Active Screen Plasma Nitriding (ASPN) process of high speed steel planing knives used in woodworking. The Taguchi approach was applied for development of the plan of experiments and elaboration of obtained experimental results. The optimized ASPN parameters were: process duration, composition and pressure of the gaseous atmosphere, the substrate BIAS voltage and the substrate temperature. The results of the optimization procedure were verified by the tools’ behavior in the sharpening operation performed in normal industrial conditions. The ASPN technology proved to be extremely suitable for nitriding the woodworking planing tools, which because of their specific geometry, in particular extremely sharp wedge angles, could not be successfully nitrided using conventional direct current plasma nitriding method. The carried out research proved that the values of fracture toughness coefficient K Ic are in correlation with maximum spalling depths of the cutting edge measured after sharpening, and therefore may be used as a measure of the nitrided planing knives quality. Based on this criterion the optimum parameters of the ASPN process for nitriding high speed planing knives were determined.

Suppression of ALD-Induced Degradation of Ge MOS Interface Properties by Low Power Plasma Nitridation of GeO2

A high quality interfacial layer (IL) is important to realize advanced high-k/Ge gate stacks for Ge metal oxide semiconductor (MOS) devices. Here, GeO2 can be regarded as one of the most promising interfacial layers (ILs). However, significant degradation of ultra thin GeO2 IL after atomic layer deposition (ALD) of high-k films has been reported, making it difficult to integrate GeO2 with high-k gate dielectrics. In this study, an in-situ plasma nitridation method is employed for plasma oxidized GeO2 layers in order to realize GeO2-based ILs robust against ALD processes, resulting in a GeON layer with tunable nitrogen concentration. The impact of the nitrogen content on the properties of GeON IL is examined. It is found that the GeON IL with low nitrogen content exhibits good MOS interface properties, inherent to the GeO2/Ge interface, as well as its tolerance for ALD-induced damages.

A new method for deposition of nano sized titanium nitride on steels

Active screen plasma nitriding is a new and common method for deposition of Iron nitride. Since techniques such as Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD) and Plasma Assisted Chemical Vapor Deposition (PACVD) are usually applied in order to deposit the titanium nitride and each of these methods has its own problems, in this research active screen plasma nitriding method was introduced as a novel approach for deposition of nano sized titanium nitride. H11 tool steel samples were coated by plasma nitriding method at 550 °C for 5, 7.5 and 10 h, using three gas mixtures consisted of H 2/N 2 = 3, 1 and 1/3. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) were employed to investigate the coating properties such as grain size, layer thickness and chemical composition. Results showed that the proportion of H 2 in the gas mixture was a crucial point in order to obtain a perfect coating. By increasing the coating time, the grain size and the layer thickness increased. XPS results showed that the coating was mainly consisted of TiN + TiN 0.1 together with a small amount of TiO 4.

Comparison oF Electrical Measurements with Structural Analysis oF Thin High-k Hafnium-based Films

We present a detailed characterization of thin high-k Hf-based dielectric/SiO2 stacks on Si by electrical measurements (capacitance - voltage (C-V) and current-voltage (I-V)), structural analysis using transmission electron microscopy (TEM) and compositional analysis using medium energy ion scattering (MEIS). We show that the electrical results are consistent with and can be explained by the structural and compositional results. Specifically, the structural results show that the effect of nitridation of the films using a decoupled plasma nitridation method is an increase in SiO2 thickness, which results in a capacitance and leakage current decrease, revealed by the electrical measurements. Nitridation also reduces the density of interface traps for these samples. The reduction is more effective in the case of nonstoichiometric hafnium silicate films (HfSiOx) than in the case of HfO2.

HfO x N y gate dielectric on p-GaAs

Plasma nitridation method is used for nitrogen incorporation in HfO2 based gate dielectrics for future GaAs-based devices. The nitrided HfO2 (HfOxNy) films on p-GaAs improve metal-oxide-semiconductor device characteristics such as interface state density, accumulation capacitance, hysteresis, and leakage current. An equivalent oxide thickness of 3.6 nm and a leakage current density of 10−6 A cm−2 have been achieved at VFB−1 V for nitrided HfO2 films. A nitride interfacial layer (GaAsO:N) was observed at HfO2–GaAs interface, which can reduce the outdiffusion of elemental Ga and As during post-thermal annealing process. Such suppression of outdiffusion led to a substantial enhancement in the overall dielectric properties of the HfO2 film.