Wyniki wyszukiwania - BazTech

1

The influence of plasma nitriding process conditions on the microstructure of coatings obtained on the substrate of selected tool steels

Mokrzycka Magdalena, Przybyło Adrianna, Góral Marek, Kościelniak Barbara, Drajewicz Marcin, Kubaszek Tadeusz, Gancarczyk Kamil, Gradzik Andrzej, Dychtoń Kamil, Poręba Marek, Jopek Jakub, Pytel Maciej

Advances in Mechanical and Materials Engineering

|

2024

|

Vol. 41, nr 1

5-16

EN

This study presents the results of research into the influence of the time of the plasma nitriding process on the microstructure of the coatings obtained. Cold-work tool steels (60WCrV8, 90MnCrV8, 145Cr6), hot-work tool steel (X37CrMoV5-1) and high-speed tool steel (HS6-5-2) were selected as substrate material. The processes were carried out under industrial conditions using an Ionit device from Oerlikon Metaplas with variable process times of 2, 4 and 6 hours. According to literature data, a nitriding mixture consisting of 5% nitrogen and 95% hydrogen was chosen, which allowed the expected diffusion layer to be obtained without a white layer (composed of iron nitrides). Analysis of elemental mapping indicates that the presence and content of nitride-forming elements influences the formation of alloy additive nitrides in the microstructure of the diffusion layer. It was also found that an increase in the duration of plasma nitriding, results in an increase in the depth of the nitrided layers formed on the substrate of high-alloy steels: X37CrMoV5-1 and HS6-5-2. Nitrides of alloying additives, present in the diffusion layer, are formed in the high-alloyed the hot-work steel X37CrMoV5-1, indicating that these steels are the most suitable for plasma nitriding of the entire tool steels analysed.

PL

W pracy przedstawiono wyniki badań wpływu czasu procesu azotowania plazmowego na mikrostrukturę otrzymanych powłok. Jako materiał podłoża wybrano stale narzędziowe do pracy na zimno (60WCrV8, 90MnCrV8, 145Cr6), stale narzędziowe do pracy na gorąco (X37CrMoV5-1) oraz szybkotnące (HS6-5-2). Procesy prowadzono w warunkach przemysłowych z wykorzystaniem urządzenia Ionit firmy Oerlikon Metaplas ze zmiennymi czasami procesu 2, 4 i 6 godzin. Zgodnie z danymi literaturowymi wybrano mieszaninę azotującą składającą się z 5% azotu i 95% wodoru, co pozwoliło na uzyskanie oczekiwanej warstwy dyfuzyjnej bez warstwy białej (złożonej z azotków żelaza). Analiza mapowania pierwiastkowego wskazuje, że obecność i zawartość pierwiastków azototwórczych w pływa na powstawanie azotków dodatku stopowego w mikrostrukturze warstwy dyfuzyjnej. Stwierdzono również, że wydłużenie czasu azotowania plazmowego powoduje zwiększenie głębokości warstw azotowanych powstających na podłożu ze stali wysokostopowych: X37CrMoV5-1 i HS6-5-2. Azotki dodatków stopowych, obecne w warstwie dyfuzyjnej, powstają w wysoko-stopowej stali do pracy na gorąco X37CrMoV5-1, co wskazuje, że stale te są najbardziej odpowiednie do azotowania plazmowego spośród wszystkich analizowanych stali narzędziowych.

2

Influence of plasma glow discharge on nitriding process of technical titanium

Pilarska M., Frączek T.

Journal of Achievements in Materials and Manufacturing Engineering

|

2017

|

Vol. 85, nr 1

21--25

EN

Purpose: This article compares selected properties of surface layers produced by plasma nitriding. Additionally, the temperature at the onset of the production of surface layers with uniform characteristics over the entire sample surface was determined. Design/methodology/approach: The selected properties of the surface layers were compared using the following test methods: microhardness measurement by the Knoop method, GDEOS profile analysis, XRD analysis, topography analysis. Findings: It was found that nitriding in plasma glow discharge at 700°C results in obtaining homogeneous surface layers over the entire surface of the sample Research limitations/implications: The ion nitride processes did not allow a complete reduction in the oxygen content. Practical implications: The adopted plasma nitriding parameters will allow homogeneous properties of the surface layers over the entire surface of the sample to be obtained. Originality/value: The effect of plasma glow discharge on the properties of surface layers was determined.

3

Direct current and pulsed direct current plasma nitriding of ferrous materials a critical review

Łępicka M., Grądzka-Dahlka M.

Acta Mechanica et Automatica

|

2016

|

Vol. 10, no. 2

150--158

EN

Nowadays, the improvement of ferrous materials performance is a problem of high interest. One of well-known wear- and corrosion properties improving technique is plasma nitriding, in which elemental nitrogen is introduced to the surface of a metal part for subsequent diffusion into the material. As a result, a compound, “white” layer and a diffusion zone are formed at the detail’s surface. Most of the authors positively describe the effects of surface ion nitiding. On the other hand, there are also reports on adverse effects of direct current and pulsed direct current plasma nitriding on ferrous materials performance. Therefore, an attempt to provide comprehensive summary on direct current and pulsed direct current ion nitriding and its influence on ferrous materials’ mechanical and corrosion properties has been made. According to the results, some of the technique drawbacks are hard to avoid in mass production.

4

Effect of plasma nitriding process conditions on corrosion resistance of 440B martensitic stainless steel

Łępicka M., Dahlke M.

Acta Mechanica et Automatica

|

2014

|

Vol. 8, no. 3

156--159

EN

Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18) stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively) in two different temperature ranges (380 or 450°C) specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

5

Optimized plasma nitriding processes for efficient wear reduction of forging dies

Paschke H., Weber M., Braeuer G., Yilkiran T., Behrens B. A., Brand H.

Archives of Civil and Mechanical Engineering

|

2012

|

Vol. 12, no. 4

407--412

EN

Plasma nitriding treatments are approved to reduce wear occurring in the field of hot forging applications. But there are demands for a further optimization of the processes in order to achieve adapted properties for differently loaded forging tools. This work presents the influence of main process parameters on the wear behavior of dies. The focused steel material of this work is DIN-X38CrMoV5-1 (1.2343), a standard hot forming tool steel. The influence of nitriding parameters like temperature, nitrogen flow and time on the nitriding depth, hardness and crack sensitivity has been investigated. Comparative application tests show the influence of different surface treatments on the wear behavior and lifetime of forging tools in an industrial environment.

6

Behaviour of nitrided layers subjected to influence of hydrogen

Ćwiek J., Baczyńska M.

Archives of Materials Science and Engineering

|

2010

|

Vol. 43, nr 1

30-41

EN

Purpose: of this paper is evaluation of behaviour of plasma nitrided layers subjected to influence of internal and external hydrogen. Properties of nitrided layers like: hydrogen permeation and trapping, fracture mode, and plasticity were examined. Design/methodology/approach: Structural low-alloy steel was nitrided at glow discharge in the gas mixture of various N2, H2, and Ar content. Samples with nitrided layers were subjected to cathodic hydrogen charging in acid solution simulating the aged engine oil hydrogenating environment. The effect of the nitrided layers on the hydrogen transport and on the irreversible trapping was evaluated by the measurements of the hydrogen permeation rate and by the vacuum extraction, respectively. Surfaces with modified layers were examined with the use of a scanning electron microscope (SEM) before and after hydrogen permeation tests. Slow strain rate test (SSRT) on samples with and without nitrided layers was carried out in hydrogen generating environment. After SSRT fracture mode and plasticity of nitrided layers were examined with SEM. Findings: In the presence of the not defected compact nitride layer, no hydrogen permeation through the steel has been stated under the experimental conditions. Influence of hydrogen content in working atmosphere, i.e. internal hydrogen, was found. Absorbed hydrogen, i.e. external hydrogen, was accumulated within this layer. Research limitations/implications: There is no possibility to perform direct observations of exact mechanism of hydrogen-assisted cracking so far. Further research should be taken to reveal the exact mechanism of increased plasticity of nitrided layer with absorbed hydrogen. Practical implications: Plasma nitrided layers are effective barriers to hydrogen entry into structural steel utilised in aggressive environments, which is especially important in the case of possible hydrogen charging of exploited steel. Originality/value: Using the atmosphere of the higher nitrogen to hydrogen ratio at plasma assisted nitriding provides the formation of thin compact nitride zone, highly protective against corrosion and hydrogen degradation. Evidences of a likely increased plasticity of nitrided layers with absorbed hydrogen was observed.

7

Plasma nitriding as a prevention method against hydrogen degradation of steel

Ćwiek J.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 36, nr 1

25-32

EN

Purpose: of this paper is evaluation of susceptibility to hydrogen degradation of structural low-alloy steel, plasma nitrided in the atmosphere with various contents of N2 and H2. Design/methodology/approach: Susceptibility of 34CrAlNi7-10 steel and samples with various plasma nitrided layers have been evaluated under monotonically increasing load in 0.005 M H2SO4 solution. The nitrided layers were investigated with the use of an X-ray Photoelectron Spectroscopy (XPS) and Auger Electrons Spectroscopy (AES). Slow-Strain Rate Tensile (SSRT) test was carried out under cathodic polarisation. Elongation, reduction in area, fracture energy and tensile strength were chosen as measures of susceptibility to hydrogen embrittlement. Fracture modes of failed samples were examined with the use of Scanning Electron Microscope (SEM). Findings: All tested samples revealed susceptibility to hydrogen degradation under hydrogenation. Samples with nitrided layer have lower lost of reduction in area than base metal samples. The nitrided layer established in standard atmosphere 30% H2 and 70% N2 has the highest resistance to hydrogen degradation. Research limitations/implications: Further research should be taken to reveal the exact mechanism of increased plasticity of nitrided layer with absorbed hydrogen. Practical implications: Plasma nitriding may prevent hydrogen charging of machines and vehicles parts in hydrogen generating environments, and thus decreasing susceptibility to hydrogen embrittlement. Originality/value: Under the increasing load and hydrogen generating environments plasma nitrided layers are effective barriers to hydrogen entry into a bulk of steel, and additionally increased plasticity of nitrided layers with absorbed hydrogen has been observed.

8

Investigation of surface properties of high temperature nitrided titanium alloys

Koyuncu E., Kahraman F., Karadeniz Ö.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 37, nr 2

434-441

EN

Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys. Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, X-Ray diffraction and Vickers hardness. Findings: Two layers were determined by optic inspection on the samples that were called the compound and diffusion layers. Compound layer contain TiN and Ti2N nitrides, XRD results support in this formations. Maximum hardness was obtained at 10h treatment time and 1000°C treatment temperature. Micro hardness tests showed that hardness properties of the nitrided samples depend on treatment time and temperature. Practical implications: Titanium and its alloys have very attractive properties for many industries. But using of titanium and its alloys is of very low in mechanical engineering applications because of poor tribological properties. Originality/value: The nitriding of titanium alloy surfaces using plasma processes has already reached the industrial application stage in the biomedical field.

9

Comparison of the PVD coatings

Polok-Rubiniec M., Dobrzański L., Adamiak M.

Archives of Materials Science and Engineering

|

2009

|

Vol. 38, nr 2

118-125

EN

Purpose: of the paper was comparison of the structure, adhesion and wear resistance of the monolayers CrN and TiN PVD coatings deposited onto plasma nitrited X37CrMoV5-1 type hot work tool steel. Design/methodology/approach: Diffraction and thin film structue were tested with the use of the transmision electron microscopy. The surfaces’ thopography and the structure of the PVD coatings were observed on the scanning electron microscopy.The evaluation of the adhesion of coatings to the substrate was made using the scratch test. The wear and friction tests were performed on a pin-on-disc device at the room temperature and at the temperature of 500°C. Findings: The best wear resistance in both conditions (20°C, 500°C temperature) demonstrate the TiN coating. These test results correspond with the very good adhesion of the coating to the substrate material and its high hardness. The critical load Lc5 (coating total delamination) lies within the range 86-92 N, depending on the coating type. It was revealed that the coating damage mechanism in the scrtch test commences in all cases with the widespread coating at the edge of the scratch being made and next develops depending on the coating type and location of the originated defects. Practical implications: The good properties of the plasma nitriding and the PVD coatings make them suitable in various engineering and industrial applications. Originality/value: The duplex surfaces treatment of the hot work tool steel for tools made for work at the elevated temperature improves their abrasion wear resistance significantly, compared to coatings developed with the PVD process.

10

Efektywne wykorzystanie energii elektrycznej w piecach jarzeniowych

Niedbała R.

Przegląd Elektrotechniczny

|

2008

|

R. 84, nr 5

71-74

PL

Zadawalające rezultaty uzyskiwane w technologiach z udziałem wyładowania jarzeniowego spychały na dalszy plan całościowe rozwiązania urządzeń i planowanie procesów energetycznych. W referacie przedstawiono cechy wyładowania jarzeniowego anormalnego w aspekcie procesów azotowania detali o różnorodnej geometrii. Podano dostrzeżone związki pomiędzy charakterystykami energetycznymi wyładowania jarzeniowego a stratami cieplnymi. Na podstawie zebranych doświadczeń określono wzajemne współdziałanie układów zasilających z odpowiednimi konstrukcjami pieców, które mogą przyczynić się do oszczędnego gospodarowanie energią elektryczną podczas długotrwałych procesów technologicznych.

EN

Satisfying results obtained in technologies using the glow discharge processes, played down the globar constructional solutions of installations and planning of processes from the point of view of rational use of energy. In the paper the features of abnormal glow discharge, applied to nitriding parts of various shapes, are presented. The observed relations between energy characteristics of glow discharge and heat losses were given. On the ground of experiments was determined the cooperation of supply units with different constructions of furnaces, that could make possible the saving of electric energy used at longlasting technological processes.

11

Efektywne wykorzystanie energii elektrycznej w piecach jarzeniowych

Niedbała R.

Przegląd Elektrotechniczny

|

2008

|

R. 84, nr 7

56-59

PL

Zadawalające rezultaty uzyskiwane w technologiach z udziałem wyładowania jarzeniowego spychały na dalszy plan całościowe rozwiązania urządzeń i planowanie procesów energetycznych. W referacie przedstawiono cechy wyładowania jarzeniowego anormalnego w aspekcie procesów azotowania detali o różnorodnej geometrii. Podano dostrzeżone związki pomiędzy charakterystykami energetycznymi wyładowania jarzeniowego a stratami cieplnymi. Na podstawie zebranych doświadczeń określono wzajemne współdziałanie układów zasilających z odpowiednimi konstrukcjami pieców, które mogą przyczynić się do oszczędnego gospodarowanie energią elektryczną podczas długotrwałych procesów technologicznych.

EN

Satisfying results obtained in technologies using the glow discharge processes, played down the globar constructional solutions of installations and planning of processes from the point of view of rational use of energy. In the paper the features of abnormal glow discharge, applied to nitriding parts of various shapes, are presented. The observed relations between energy characteristics of glow discharge and heat losses were given. On the ground of experiments was determined the cooperation of supply units with different constructions of furnaces, that could make possible the saving of electric energy used at longlasting technological processes.

12

Investigation of surface properties of high temperature nitrided titanium alloys

Koyuncu E., Kahraman F., Karadeniz O.

Archives of Materials Science

|

2008

|

Vol. 29, nr 1-2

50-62

EN

Titanium and its alloys have very attractive properties for many industries. But using of titanium and its alloys are very low in mechanical engineering applications because of poor tribological properties. In this study, surface modification of Ti6Al4V titanium alloy has been made with various temperatures by plasma nitriding process. Plasma nitriding treatment has been performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000 degree C. Surface properties of plasma nitrided Ti6Al4V alloy was examined by metalographic inspection, X-Ray difraction and vichers hardness. Two layers were determined by optic inspection on the samples that called compound and diffusion layers. Compound layer contain TiN and Ti2N nitrides, XRD results support in this formations. Maximum hardness has been obtained at 10h treatment time and 1000 degree C treatment temperature. Micro hardness tests showed that hardness properties of the nitrided samples depend on treatmant time and temperature.

13

Wyładowanie jarzeniowe w urządzeniach do obróbek powierzchniowych metali

Niedbała R.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Techniczne

|

2007

|

Z. 5

11-20

PL

Zadawalające rezultaty uzyskiwane w technologiach z udziałem wyładowania jarzeniowego spychały na dalszy plan całościowe rozwiązania urządzeń i planowanie procesów energetycznych. W referacie przedstawiono cechy wyładowania jarzeniowego anormalnego w aspekcie procesów azotowania detali o różnorodnej geometrii. Podano dostrzeżone związki pomiędzy charakterystykami energetycznymi wyładowania jarzeniowego a stratami cieplnymi. Na podstawie zebranych doświadczeń określono wzajemne współdziałanie układów zasilających z odpowiednimi konstrukcjami pieców, które mogą przyczynić się do oszczędnego gospodarowanie energią elektryczną podczas długotrwałych procesów technologicznych.

EN

Satisfying results obtained in technologies using the glow discharge processes, played down the globar constructional solutions of installations and planning of processes from the point of view of rational use of energy. In the paper the features of abnormal glow discharge, applied to nitriding parts of various shapes, are presented. The observed relations between energy characteristics of glow discharge and heat losses were given. On the ground of experiments was determined the cooperation of supply units with different constructions of furnaces, that could make possible the saving of electric energy used at longlasting technological processes.

14

Comparison of the adhesion and wear resistance of the PVD coatings

Polok-Rubiniec M., Dobrzański L. A., Adamiak M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 20, nr 1-2

279-282

EN

Purpose: of the paper was comparison of the adhesion and antiwear properties of the multilayer TiN/(Ti,Al)N PVD coatings deposited onto heat treated and plasma nitrided X37CrMoV5-1 type hot work tool steel. Design/methodology/approach: Hardness test of the investigated specimens from hot work steel in the heat treated state has been made using Rockwell method. The distribution of microhardness in the nitriding layer measured using Vickers micro-hardness testing method. The evaluation of the adhesion of coatings to the substrate was made using the scratch test. Wear resistance tests with the pin-on-disc method were carried out on the CSEM THT (High Temperature Tribometer) device at the room temperature and at the temperature of 500 degrees centigrade. The friction coefficient between the ball and disc was measured during the test. Findings: In case of the TiN(Ti,Al)N coating deposited onto the X37CrMoV5-1 nitrided hot work steel show a very good adhesion which has been revealed to the substrate material is comparison to the TiN/(Ti,Al)N coating deposited onto heat treated hot work steel. Taking into account the results of measurements, one can state that the lowest wear at certain conditions in both room and elevated temperatures show TiN(Ti,Al)N deposited onto plasma nitrided X37CrMo V5-1 hot work steel type. Practical implications: The investigation results will provide useful information to applying of the TiN/(Ti,Al)N PVD coating for the improvement of wear resistance of tools made from hot work steels. Originality/value: The paper contributes to better understanding the wear resistance at the elevated temperature to 500 degrees centigrade of the multilayer TiN/(Ti,Al)N PVD coating deposited onto heat treated and plasma nitrided hot work tool steel.

15

Hydrogen charging of plasma nitrided steel in acid solution

Sobieszczyk S., Łunarska E., Ćwiek J., Zieliński A., Nikiforow K.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

205--208

EN

Purpose: Purpose of this paper is evaluation of susceptibility of plasma nitrided structural steel to hydrogen absorption. Design/methodology/approach: Structural steel, nitrided at glow discharge in the gas mixture of various N2, H2, Ar content was subjected to cathodic hydrogen charging in acid solution simulating the aged engine oil. The effect of the nitrided layers on the hydrogen transport and on the irreversible trapping was evaluated by the measurements of the hydrogen permeation rate and by the vacuum extraction, respectively. Findings: In the presence of the not defected compact nitride layer, no hydrogen permeation through the steel has been stated under the experimental conditions. Absorbed hydrogen was accumulated within this layer. Research limitations/implications: Further research should be taken to evaluate the influence of compact nitride zone on hydrogen degradation under tensile stress. Practical implications: Plasma nitriding treatment could improve the properties of the low-alloy high-strength structural steels exploited in aggressive environments, which is especially important in the case of possible hydrogen charging of exploited steel. Originality/value: Using the atmosphere of the higher nitrogen to hydrogen ratio at plasma assisted nitriding provides the formation of thin compact nitride zone, highly protective against corrosion and hydrogen degradation.

16

Effect of plasma nitrided layers on low-alloy steel on its hydrogen degradation

Zieliński A., Ćwiek J., Błaszkiewicz B.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 17, nr 1-2

213--216

EN

Purpose: Purpose of this paper is evaluation of susceptibility to hydrogen degradation of structural low-alloy steel, plasma nitrided in the atmosphere with various contents of N2 and H2. Design/methodology/approach: Susceptibility of 34CrAlNi7-10 steel and samples with various plasma nitrided layers have been evaluated under monotonically increasing load in 0.005 M H2SO4 solution. Slow-strain rate tensile test (SSRT) test was carried out under cathodic polarisation. Elongation, reduction in area, fracture energy and tensile strength were chosen as measures of susceptibility to hydrogen embrittlement. Fracture modes of failed samples were examined with the use of scanning electron microscope (SEM). Findings: All tested samples revealed susceptibility to hydrogen degradation under hydrogenation. Samples with nitrided layer have lower lost of reduction in are than base metal samples. The nitrided layer established in standard atmosphere 30% H2 and 70% N2 has the highest resistance to hydrogen degradation. Research limitations/implications: Further research should be taken to reveal the exact mechanism of increased plasticity of nitided layer with absorbed hydrogen. Practical implications: Plasma nitriding may prevent hydrogen charging of machines and vehicles parts in hydrogen generating environments, and thus decreasing susceptibility to hydrogen embrittlement. Originality/value: Under the increasing load and hydrogen generating environments plasma nitrided layers are effective barriers to hydrogen entry into a bulk of steel, and additionally increased plasticity of nitrided layers with absorbed hydrogen was observed.

17

Jakość i precyzja – przekładnie planetarne Apex Dynamics

Szumiec G.

Napędy i Sterowanie

|

2005

|

R. 7, nr 6

22--23

PL

Przekładnie planetarne są wśród konstruktorów maszyn urządzeniami znanymi i wykorzystywanymi od wielu lat. Ich charakterystyczne cechy, takie jak zwarta konstrukcja w połączeniu z dużymi przełożeniami oraz wysoka sztywność, zostały wykorzystane w wielu aplikacjach. Zasada działania przekładni planetarnych nie zmieniła się, natomiast zwiększyły się wymagania względem żywotności przekładni, wartości przenoszonych momentów obrotowych, a także głośności pracy i luzów.

18

Wpływ parametrów azotowania plazmowego na korozyjne zachowanie austenitycznej stali nierdzewnej

Mańkowski J.

Ochrona przed Korozją

|

2004

|

nr 12

327-332

PL

Badano wpływ warunków azotowania plazmowego austenitycznej stali nierdzewnej Cr18Ni9Ti na jej korozyjne zachowanie. Azotowanie plazmowe prowadzono w niskoazotowej atmosferze (25%N2 + 75%H2) albo w wysokoazotowej atmosferze (80%N2+20%H2) w temperaturze 585oC w ciągu 6 godzin lub 16 godzin. Krzywe polaryzacji mierzono w 25oC w roztworach 0,05 M Na2SO4 i 0,05 M Na2SO4 + 0,1 M NaCl, zakwaszonych do pH 3,0, na wyjściowych powierzchniach azotowanych oraz po ich zeszlifowaniu do różnych głębokości w obrębie warstwy azotowanej. Azotowanie w niskoazotowej atmosferze prowadziło do utworzenia warstw azotowanych o obniżonej odporności korozyjnej w obrębie strefy związków i podwarstwy dyfuzyjnej, zwłaszcza w przypadku stali azotowanej przez 6 godzin. Warstwy te ulegały korozji wżerowej przy potencjale -0,30 VNEK , który był o ok. 0,9 V niższy od potencjału korozji wżerowej stali nieazotowanej. Azotowanie plazmowe w wysokoazotowej atmosferze przez 6 godzin lub 16 godzin pozwalało otrzymać warstwy o dobrej odporności korozyjnej w roztworze siarczanowym w zakresie głębokości do ok. 40 mm. W roztworze chlorkowo-siarczanowym stal azotowana przez 6 godzin ulegała korozji wżerowej przy potencjałach znacznie niższych niż stal nieazotowana, natomiast na stali azotowanej przez 16 godzin korozja wżerowa pojawiała się przy potencjałach bliskich potencjałowi korozji wżerowej stali nieazotowanej.

EN

The influence of plasma nitriding conditions on the corrosion resistance of Cr18Ni9Ti austenitic stainless steel was investigated. Plasma nitriding was performed in a low nitrogen atmosphere (25 vol.-% N2+75%-vol. H2) and in a high nitrogen atmosphere (80 vol.-% N2+20%-vol. H2) for 6h and for 16h at 585°C. Anodic polarization curves were measured at 25° C in 0.05 M Na2SO4 and in 0.05 M Na2SO4 + 0.1M NaCl solutions of pH 3.0 on the as-nitrided surfaces and after their abrasion to various depths within the nitrided layer. Nitriding in the low nitrogen atmosphere resulted in the formation of nitrided layers of decreased corrosion resistance in the region of compound zones and diffusion sublayers, especially in the case of the steel nitrided for 6 h. These layers underwent pitting corrosion at a potential of -0.30 VSCE, being about 0.9 V lower than that for unnitrided steel (+0.60 VSCE). Plasma nitriding in the high nitrogen atmosphere for 6 h and 16 h produced layers with good corrosion resistance down to a depth of about 40 mm in a sulphate solution. In a chloride - sulphate solution the steel nitrided for 6 h underwent pitting corrosion at potentials much lower than in the case of unnitrided steel, however, for the steel nitrided for 16 h the pitting potentials were close to the value measured for the unnitrided steel.

19

Właściwości elektrochemiczne staliwa austeniczno-ferrytycznego azotowanego plazmowo

Stepuch-Galik A., Stypuła B.

Ochrona przed Korozją

|

2003

|

nr 7

196-199

PL

Przedstawiono właściwości elektrochemiczne staliwa LOOH21N7MCu, azotowanego plazmowo. Azotowanie przeprowadzono w plazmie o częstotliwości radiowej, w warunkach niskiego ciśnienia (0,7Tr) i w niskiej temperaturze (300°C). Właściwości elektrochemiczne staliwa badano w 0.1M roztworze NaCl w zakresie pH 1-7, stosując potencjodynamiczną technikę polaryzacyjną. Powierzchnię stopu, po azotowaniu a także po polaryzacji, analizowano za pomocą rentgenowskiej spektroskopii fotoelektronów, XPS. Powierzchnia azotowana posiadała lepsze parametry pasywacyjne i wyższą odporność na korozję (także lokalną) w porównaniu z powierzc-nią nieazotowaną. Wyższa odporność staliwa azotowanego związana jest z wysoką zawartością azotu w warstwie powierzchniowej (ok. 21% at.) i wzbogaceniem warstwy w pierwiastki stopowe, głównie krzem i chrom.

EN

This paper presents results from study of electrochemical behaviour of plasma nitrid-ing of cast stainless steel LOOH2JN7MCU. Rf plasma nitriding was conducted under low pressure and low temperature conditions (0,7Tr, 300°C). The electrochemical behaviour of the alloy was examined in 0.1 M NaCl solutions at 1-7pH values, using potentiodynamic method at scan rate of 10 mV Is. The analysis of the surfaces of the cast steel, after nitriding and after polarisation was performed with X-ray photoelectron spectroscopy (XPS). Nitrided surface shows better parameters of passivation and better corrosion resistance than unnitrided (also to local corrosion). High corrosion resistance of nitrided cast steel is connected with high concentration of nitrogen in the surface layer (about 21% at.) and with the segregation of alloying elements, mainly silicon and chromium.

20

Wear resistance of hard coatings on different steel substrate.

Skorič B., Kakas D.

Zagadnienia Eksploatacji Maszyn

|

1998

|

Vol. 33, nr 2

293-300

EN

Hard coatings like TiN or TiAlN, deposited by sputtering processes are widely used for the wear protection of tool and machine parts. The optimization procedure for coated parts could be more effective, knowing more about the fundamental physical and mechanical properties of a coating. Magnetron sputtering as a PVD technique has specific advantages for the deposition of complex coating materials because of making posiible to produce different type of surface layers. To enhance the adhesion of the coating a plasma nitriding, conventional and on low pressure, of substrates is used. In this case plasma nitriding, plasma nitriding at low pressure, plasma single layers (TiN or TiAlN) and combined plasma technologies (PN/TiN or PNlp/TiAlN) were used to produce different surface on steels to reach optimal quality of surface.

PL

Twarde powłoki, jak TiN oraz TiAlN osadzone w procesie rozpylania są szeroko używane jako ochrona przed zużyciem narzędzi i maszyn. Procedury optymalizacyjne dla elementów z powłokami mogą być bardziej efektywne pod warunkiem znajomości podstawowych własności fizycznych i mechanicznych powłok. Magnetronowe napylanie znane jako technika PVD ma specyficzne zalety w nakładaniu złożonych materiałów, ponieważ umożliwia wytwarzanie różnych rodzajów warstw powierzchniowych. W celu zwiększenia adhezji powłoki stosuje się plazmowe azotkowanie podkładu zarówno konwencjonalne, jak i przy niskim ciśnieniu. W tym przypadku użyto azotkowania plazmowego, azotkowania plazmowego pod obniżonym ciśnieniem, plazmowej pojedynczej warstwy (TiN lub TiAlN) i kombinowanej technologii plazmowej (PN/TiN lub PNNlp/TiAlN) w celu wytworzenia różnych powierzchni na stalach dla uzyskania optymalnej jakości powierzchni.