Plasma Electrolytic Carbonitriding Research Articles

Duplex Surface Treatment of Pre-Electroplating and Pulsed Nanocrystalline Plasma Electrolytic Carbonitriding of Mild Steel

Recently, new duplex surface treatments involving the use of pre-electroplating and pulsed plasma electrolytic nitrocarburizing (PPEN/C) have led to the possibility of using this material for applications usually typical for tool steels. In this work, we present results concerning the duplex treatment of pre-electroplating of Cr and PPEN/C of AISI 1020 mild steel. The samples were electroplated in a plating bath. After electroplating, the samples were nitrocarburized. The effects of time and applied voltage of PPEN/C process were discussed. The samples were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and microhardness testing. Electroplated layers of up to 100 μm were obtained. The subsequent PPEN/C increased the surface hardness to 1200 HV0.2 due to the formation of nitrides and carbides. Decreasing the size of nanocrystalline carbonitrides will lead to improvement of their wear resistance significantly.

Study of bipolar pulsed nanocrystalline plasma electrolytic carbonitriding on nanostructure of compound layer

Surface hardening of commercially pure titanium by using bipolar pulsed nanocrystalline plasma electrolytic carbonitriding was studied in this investigation. The coating process was performed on triethanolamine-based electrolyte by a cooling bath. The nanostructure of the obtained compound layer was examined with figure analysis of SEM nanographs. The effects of process variables, i.e., triethanolamine concentration, electrical conductivity of electrolyte, applied voltage, and treatment time, have been experimentally studied. Statistical methods were used to achieve the optimum size of nanocrystals. Finally, the contribution percentage of effective factors of pulsed current was revealed and confirmation runs showed the validity of the obtained results.

Study of bipolar pulsed nanocrystalline plasma electrolytic carbonitriding on nanostructure of compound layer for CP-Ti

Surface hardening of commercially pure titanium using bipolar pulsed nanocrystalline plasma electrolytic carbonitriding has been studied in this investigation. The coating process has been performed on triethanolamine-based electrolytes using a cooling bath. The nanostructure of obtained compound layers was examined with figure analysis of SEM nanographs. The effects of process variables (i.e., frequency, temperature of electrolytes, applied voltage, and treatment time) have been studied experimentally. Statistical methods were used to achieve the optimum size of nanocrystals. Finally, the contribution percentage of the effective factors of pulsed current was revealed, and confirmation showed the validity of obtained results. It has also been revealed that by changing the size of nanocrystalline carbonitrides, other properties of the coating will change significantly.

Mechanical properties of Ti(C 0.7N 0.3) film produced by plasma electrolytic carbonitriding of Ti6Al4V alloy

Porous nanocrystalline Ti(C 0.7N 0.3) film on Ti6Al4V substrate was prepared by plasma electrolytic carbonitriding (PECN). The film was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM, EDX, TEM, FESEM, Rockwell C indenter, scratch tester, Vickers microhardness tester and ring-on-block tribometer. The results showed that the film was about 15 μm thick and its hardness was Hv 2369 at a load of 0.2 N. The adhesion of the film was characterized by Lc and Pc value, and was found to be about 42 N and more than 800 N, respectively. The friction coefficients and wear volume loss of the PECN-treated samples sliding against a steel counterpart were much less than those of the untreated Ti6Al4V. The film possessed a good wear-resistance and antifriction under oil-lubricated condition due to its high hardness, adhesion and fracture toughness. Also, the porous surface morphology of the Ti(C 0.7N 0.3) film contributed to the enhanced tribological resistance by promoting the formation of lubricant film and entrapping wear debris.

Study of bipolar pulsed plasma electrolytic carbonitriding on nanostructure of compound layer for a gamma Ti-Al alloy

The surface hardening of a gamma Ti-Al alloy by using bipolar pulsed nanocrystalline plasma electrolytic carbonitriding has been studied in this investigation. Coating process was performed on a triethanolaminebased electrolyte by a cooling bath. The nanostructure of the obtained compound layer was examined with the figure analysis of the scanning electron microscopy (SEM) nanographs. The effects of the process variables, i.e., frequency, temperature of the electrolyte, applied voltage and treatment time, have been experimentally studied. Statistical methods were used to achieve the optimum size of the nanocrystals. Finally, the contribution percentage of the effective factors of the pulsed current was revealed, and the confirmation run showed the validity of the obtained results.

Erratum to: Study of nanocrystalline plasma electrolytic carbonitriding for CP-Ti

Erratum to: Study of nanocrystalline plasma electrolytic carbonitriding for CP-Ti

Electrochemical study of nanocrystalline plasma electrolytic carbonitriding of CP‐Ti

PurposeThe aim of this paper is to obtain optimal corrosion resistance of certain differently treated samples by investigation of their electrochemical properties.Design/methodology/approachNanocrystalline plasma electrolytic carbonitriding (PEC/N) treatments were applied on the surface of commercially pure titanium in a glycerol bath with different additives. The carbonitriding process was performed in a glycerol bath with different additives such as carbamide, natrium nitrate and triethanolamine. The effects of electrolyte composition on chemical composition and corrosion resistance of the PEC/N films were examined by means of X‐ray diffraction, scanning electron microscopy, potentiodynamic polarization and electrochemical impedance spectroscopy in a Ringer solution.FindingsThe results showed that the PEC/N films obtained in solutions with triethanolamine (T‐film) had better corrosion resistance. All coated samples had a better electrochemical behaviour compared with the untreated substrate. Different nano‐structures and morphologies were obtained by different additives in electrolyte.Practical implicationsThe results obtained in this research into nanocrystalline PEC/N can be used wherever good corrosion and wear resistance with the highest efficiency is required.Originality/valueThe speed of treatment by this technique makes this method very suitable for the industrial surface treatment of different components.

Study of nanocrystalline plasma electrolytic carbonitriding for CP-Ti

Commercially pure titanium is subjected to carbonitriding according to a new procedure called plasma electrolytic carbonitriding. The influence of voltage and time on the thickness of carbonitrided layers is investigated. The kinetics of growth of the layers is analyzed according to their thickness and microhardness. The coatings formed on the titanium substrate are multilayer. They are formed by a combination of TiN, TiO2, and the α-phase in the form of inclusions of high concentrations of nitrogen and carbon in a close-packed hexagonal crystal lattice of titanium. All layers are very hard with hardnesses varying from 1100 (Vickers-Knoop hardness) for the TiN layer and 900 for the α-phase to 250 for the nonmodified surface. There exist strong metallic bonds between the layers of the coating. The time dependence of the form t 1/2 is established for the diffusion of nitrogen and carbon in the outer layers. The results of wear tests reveal that the mass losses of carbonitrided samples become 4–17 times lower than for the intact samples. Thus, the procedure of plasma electrolytic carbonitriding enables one to get highly efficient stable coatings on titanium.

Investigation of nanocrystalline pulsed plasma electrolytic carbonitriding as novel method for wear protection of 316L austenitic stainless steel

Very few studies have focused on the optimisation of the nanocrystalline pulsed plasma electrolytic carbonitriding process parameters. A design of experiment technique, the Taguchi method, has been used to optimise the nanocrystalline pulsed plasma electrolytic carbonitriding. The experimental design consisted of four factors (triethanolamine concentration, electrical conductivity of electrolyte, applied voltage and duration of process), each containing three levels. All experiments were carried out under optimum constant frequency and duty cycle of rectangular shape pulse current method. Abrasive wear measurements were carried out to determine the wear resistance of the coated samples. The optimised coating parameters for wear resistance are 1020 g L–1 for triethanolamine concentration, 360 ms cm–1 for electrical conductivity of electrolyte, 400 V for applied voltage, 30 min for treatment time. The results showed that the applied voltage is the most significant factor affecting the wear resistance of the coatings. The wear property of the optimal coating was also investigated.

Characterization and blood compatibility of TiC xN 1 − x hard coating prepared by plasma electrolytic carbonitriding

A novel technique to form Ti(C, N) on titanium, named as plasma electrolytic carbonitriding (PEC/N) on cathode was successful used to prepare TiC x N 1 − x coating. The structure, composition and morphology of the coating were characterized by XRD, XPS and SEM, respectively. The results indicated that TiC 0.3N 0.7 as a new species appears on the surface of the titanium plate, and the thickness of the coating with porous surface morphology increases with the treated time. The blood compatibility of the TiC 0.3N 0.7 coating was evaluated by haemolysis ratios, dynamic blood clotting test, plasma recalcification time and platelet adhesion. The results indicated that the blood compatibility of the plasma-treated titanium with TiC x N 1 − x coating is significantly improved as compared to the original titanium. Additionally, the results derived from measurements of hardness and corrosion indicated that the coating has excellent mechanical and corrosion-resistant properties.

Synthesis of nanocrystallineTi (C xN 1− x) thick films on titanium by plasma electrolytic carbonitriding

A novel technique to form Ti(C,N) on titanium, named as plasma electrolytic carbonitriding (PEC/N), is proposed in this paper. The processing is performed by discharge treatments of titanium in an electrolytic solution containing triethanolamine and formamide at 600 V for 0.5–2.5 h using a pulse power supply. XRD, EDAX, and FESEM were employed to characterize the phase component, chemical composition, morphology and grain size of the PEC/N formed films. The results show that the films are composed of Ti(C x N 1− x ), appearing nanocrystalline and porous, and bond tightly to the titanium substrates. The thickness, ratios of C/N and pores sizes of the films tend to increase with discharge time. When treated for 2.5 h, the film is about 15 μm thick and its hardness is Hv 2083 at the load of 0.2 N.

Porous nanocrystalline Ti(CxN1−x) thick films by plasma electrolytic carbonitriding

Abstract Nanocrystalline Ti(CxN1 − x) films on titanium were prepared by plasma electrolytic carbonitriding (PEC/N) at 600 V in an electrolytic solution containing triethanolamine and formamide using a pulse power supply. XRD, EDAX, FESEM and TEM were employed to characterize the phase components, element composition, and microstructure of the films. Rockwell C indenter and Vicker’s indentation test were used to evaluate the adhesion and hardness of the films. The obtained results show that the films are porous and composed of Ti(CxN1 − x), without apparent discontinuity in the interfaces adjacent to the titanium substrate. The thickness, ratios of C/N and pores sizes of the films tend to increase with the discharge time. When discharge-treated for 2.5 h, the film is about 15 μm thick and exhibits nanocrystalline characterization with grain size of 40–60 nm. Its hardness is Hv 2083 at the load of 0.2 N and the adhesion, Pc value, is more than 500 N. The formation process and mechanism of the Ti(CxN1 − x) films are discussed.

The use of molybdenum in TiC-base cermets : Reader Service Dept., Climax Molybdenum Co., 1270 Avenue of the Americas, New York, N.Y. 10020, U.S.A.

Porous nanocrystalline Ti(C0.7N0.3) film on Ti6Al4V substrate was prepared by plasma electrolytic carbonitriding (PECN). The film was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM, EDX, TEM, FESEM, Rockwell C indenter, scratch tester, Vickers microhardness tester and ring-on-block tribometer. The results showed that the film was about 15 μm thick and its hardness was Hv 2369 at a load of 0.2 N. The adhesion of the film was characterized by Lc and Pc value, and was found to be about 42 N and more than 800 N, respectively. The friction coefficients and wear volume loss of the PECN-treated samples sliding against a steel counterpart were much less than those of the untreated Ti6Al4V. The film possessed a good wear-resistance and antifriction under oil-lubricated condition due to its high hardness, adhesion and fracture toughness. Also, the porous surface morphology of the Ti(C0.7N0.3) film contributed to the enhanced tribological resistance by promoting the formation of lubricant film and entrapping wear debris.

Sealing corrosive materials with hard carbon alloys : T. J. Wasil and G. P. McCleary, Lubrication Eng., 23 (6) (1967) 234–240; 6 figs., 2 tables, 10 refs.

Porous nanocrystalline Ti(C0.7N0.3) film on Ti6Al4V substrate was prepared by plasma electrolytic carbonitriding (PECN). The film was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM, EDX, TEM, FESEM, Rockwell C indenter, scratch tester, Vickers microhardness tester and ring-on-block tribometer. The results showed that the film was about 15 μm thick and its hardness was Hv 2369 at a load of 0.2 N. The adhesion of the film was characterized by Lc and Pc value, and was found to be about 42 N and more than 800 N, respectively. The friction coefficients and wear volume loss of the PECN-treated samples sliding against a steel counterpart were much less than those of the untreated Ti6Al4V. The film possessed a good wear-resistance and antifriction under oil-lubricated condition due to its high hardness, adhesion and fracture toughness. Also, the porous surface morphology of the Ti(C0.7N0.3) film contributed to the enhanced tribological resistance by promoting the formation of lubricant film and entrapping wear debris.