Structural Investigations of Iron-Based Sintered Alloys after Plasma Nitriding

Various nitriding methods are applicable, viz.: gas nitriding, nitriding in powders and plasma nitriding which is one the latest nitriding technologies applicable for parts made of constructional and tool steels. A large of motor car products made from iron-based alloying powders has been subjected to plasma nitriding process in order to enhance their surface properties like: hardness and abrasive wear. One of the main problems of chemical heat treatment alloys produced by powder metallurgy technology is their porosity degree. In the experiments Fe-Ni-Cu-Mo and Fe-Mo sintered structural parts modified by boron were made. Boron activates the sintering process which results in their considerable consolidation in the sintering at 1473 K for 60 minutes in the atmosphere of hydrogen. The experiments are related to the production of sintered structural elements based on iron powder - NC 100.24 as well as Astaloy Mo (Fe-Mo) and Distaloy SA (Fe-Ni-Cu-Mo) modified by 0.2 wt%, 0.4 wt% and 0.6 wt% B. Sintered parts were obtained by mixing powders said above, followed by compacting at 600 MPa pressure and sintered at 1473 K during 60 minutes time in hydrogen atmosphere. Selected sintered parts were plasma nitrided at 883 K during 4 hours time. After plasma nitriding microstructure morphology using light microscopy and phase identification by Xray diffraction technique have been made. The influence of structure and phase composition on the surface properties of examined sintered parts modified by boron, after plasma nitriding have been analyzed.

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(Ti,Al)O2 Whiskers Grown during Glow Discharge Nitriding of Ti-6Al-7Nb Alloy

Materials ◽

10.3390/ma14102658 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2658

Author(s):

Krzysztof Szymkiewicz ◽

Jerzy Morgiel ◽

Łukasz Maj ◽

Małgorzata Pomorska

Keyword(s):

Surface Hardening ◽

Surface Defects ◽

Plasma Nitriding ◽

Surface Roughening ◽

Effective Surface ◽

Plan View ◽

Gas Nitriding ◽

Transmission Electron ◽

Temperature Window ◽

20 Nm

Plasma nitriding of titanium alloys is capable of effective surface hardening at temperatures significantly lower than gas nitriding, but at a cost of much stronger surface roughening. Especially interesting are treatments performed at the lower end of the temperature window used in such cases, as they are least damaging to highly polished parts. Therefore identifying the most characteristic defects is of high importance. The present work was aimed at identifying the nature of pin-point bumps formed at the glow discharged plasma nitrided Ti-6Al-7Nb alloy using plan-view scanning and cross-section transmission electron microscopy methods. It helped to establish that these main surface defects developed at the treated surface are (Ti,Al)O2 nano-whiskers of diameter from 20 nm to 40 nm, and length up to several hundreds of nanometers. The performed investigation confirmed that the surface imperfection introduced by plasma nitriding at the specified range should be of minor consequences to the mechanical properties of the treated material.

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RF plasma nitriding of severely deformed iron-based alloys

Materials Science and Engineering A ◽

10.1016/s0921-5093(02)00687-1 ◽

2003 ◽

Vol 348 (1-2) ◽

pp. 100-110 ◽

Cited By ~ 37

Author(s):

H Ferkel ◽

M Glatzer ◽

Y Estrin ◽

R.Z Valiev ◽

C Blawert ◽

...

Keyword(s):

Plasma Nitriding ◽

Rf Plasma ◽

Iron Based

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Effect of Low-Temperature Plasma Nitriding on Corrosion and Surface Properties of Duplex Stainless Steel UNS S32205

Journal of Materials Engineering and Performance ◽

10.1007/s11665-020-04753-6 ◽

2020 ◽

Vol 29 (4) ◽

pp. 2612-2622

Author(s):

Yamid E. Núñez de la Rosa ◽

Oriana Palma Calabokis ◽

Paulo César Borges ◽

Vladimir Ballesteros Ballesteros

Keyword(s):

Stainless Steel ◽

Low Temperature ◽

Duplex Stainless Steel ◽

Surface Properties ◽

Plasma Nitriding ◽

Low Temperature Plasma ◽

Temperature Plasma

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Influence of the Gas Pressure of Plasma Nitriding on the Structural, Mechanical and Tribological Surface Properties of AISI 316L

Materials Research ◽

10.1590/1980-5373-mr-2019-0302 ◽

2019 ◽

Vol 22 (4) ◽

Cited By ~ 1

Author(s):

Marcelo Campos ◽

Solange de Souza ◽

João Paulo Davim ◽

Sylvio Dionysio de Souza ◽

Maristela Olzon-Dionysio

Keyword(s):

Surface Properties ◽

Plasma Nitriding ◽

Gas Pressure ◽

Aisi 316L

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Corrosion Behaviour of Steel Nitrided and Nitrocarburized in Gas, Respectively

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.365.278 ◽

2015 ◽

Vol 365 ◽

pp. 278-284

Author(s):

Hisao Fujikawa ◽

H. Iwamura ◽

M. Uramoto

Keyword(s):

Corrosion Test ◽

Corrosion Behaviour ◽

Plasma Nitriding ◽

Salt Spray ◽

Salt Bath ◽

Carbon Steels ◽

Test Method ◽

Oxidation Treatment ◽

Gas Nitriding ◽

Nitride Layers

Nitriding treatment is well known as one of the corrosion protection methods for steels as well as a way to prevent wear and fatigue. Initially, salt bath nitrocarburizing was popular, but recently, gas nitriding, gas nitrocarburizing, plasma nitriding and so on have come to be used more often because of their superior nitriding ability. In the case of nitriding, only nitrogen (N) diffuses into the steel, but in the case of nitrocarburizing, both nitrogen and carbon (C) diffuse into the steel. General speaking, nitriding includes all the treatments mentioned above. The corrosion behavior of nitride carbon steels has been understood mainly by salt bath or gas nitrocarburizing treatments1)-4).However, recently, nitriding is mainly applied to parts for things such as automobiles which need protection from wear and fatigue, and is seldom used for parts which need corrosion resistance. The present paper is to remind researchers again that nitrided steels show good corrosion resistance.Therefore, the comparison of various thicknesses of nitride layers as well as the comparison between nitride layers on steel has been carried out in this examination, using the salt spray corrosion test method. The effect of oxidation treatment after nitriding was also investigated.

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A Review on Surface Engineering of Ti6Al4V Titanium Alloy Using Gas and Laser Nitriding Techniques

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.766-767.618 ◽

2015 ◽

Vol 766-767 ◽

pp. 618-625 ◽

Cited By ~ 2

Author(s):

J.R Deepak

Keyword(s):

Titanium Alloy ◽

Surface Properties ◽

Surface Engineering ◽

Surface Hardness ◽

Aircraft Engine ◽

Ti6al4v Alloy ◽

Surface Stability ◽

Laser Nitriding ◽

Gas Nitriding ◽

Grade 5

Nitriding is the most common surface engineering technique that is being used in Titanium alloys for improving their surface properties, viz hardness, wear resistance, etc. Ti6Al4V (Grade 5) Titanium Alloy is a super alloy that exhibits excellent mechanical strength; it is highly resistance to creep at very high temperatures which maintains good surface stability. It is resistant to corrosion and oxidation. The main objective of this review paper is to study the recent research works carried on Nitriding of Ti6Al4V alloy by using, viz gas Nitriding and laser Nitriding. This process is used in the surface hardening of machine parts such as aircraft engine parts, crank pins, valve seats, gears, bush, aero engine cylinders, aero crank shafts. Gas Nitriding is a diffusional technique in which the nitrogen atoms are diffused into the surface of the metal to obtain hard surface. By Laser Nitriding is a diffusional technique by which the surface properties of the titanium alloy is enhanced. Laser nitriding process comprises of various stages, viz, transport of heat, melting effect, diffusion and convection effect. By Nitriding technique the surface hardness of super alloys like Titanium Alloy Ti6Al4V Grade 5 can be increased by increasing the hardness on the surface there by its scope of application is widened. In this paper a literature survey is carried out and the recent research works on surface engineering of Ti6Al4V alloy using gas and laser Nitriding technique is summarized.

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The character of the structure formation of model alloys of the Fe-Cr-(Zr, Zr-B) system synthesized by powder metallurgy

Journal of Achievements of Materials and Manufacturing Engineering ◽

10.5604/01.3001.0014.3344 ◽

2020 ◽

Vol 2 (100) ◽

pp. 49-57

Author(s):

Z.A. Duriagina ◽

M.R. Romanyshyn ◽

V.V. Kulyk ◽

T.M. Kovbasiuk ◽

A.M. Trostianchyn ◽

...

Keyword(s):

Phase Composition ◽

Powder Metallurgy ◽

Chemical Composition ◽

Structure Formation ◽

Xrd Analysis ◽

Model Alloy ◽

Phase Identification ◽

Laves Phases ◽

Cr System ◽

Sintered Alloys

Purpose: The purpose of the work is to synthesize and investigate the character of structure formation, phase composition and properties of model alloys Fe75Cr25, Fe70Cr25Zr5, and Fe69Cr25Zr5B1. Design/methodology/approach: Model alloys are created using traditional powder metallurgy approaches. The sintering process was carried out in an electric arc furnace with a tungsten cathode in a purified argon atmosphere under a pressure of 6·104 Pa on a water cooled copper anode. Annealing of sintered alloys was carried out at a temperature of 800°C for 3 h in an electrocorundum tube. The XRD analysis was performed on diffractometers DRON-3.0M and DRON-4.0M. Microstructure study and phase identification were performed on a REMMA-102-02 scanning electron microscope. The microhardness was measured on a PMT-3M microhardness meter. Findings: When alloying a model alloy of the Fe-Cr system with zirconium in an amount of up to 5%, it is possible to obtain a microstructure of a composite type consisting of a mechanical mixture of a basic Fe2(Cr) solid solution, solid solutions based on Laves phases and dispersive precipitates of these phases of Fe2Zr and FeCrZr compositions. In alloys of such systems or in coatings formed based on such systems, an increase in hardness and wear resistance and creep resistance at a temperature about 800°C will be reached. Research limitations/implications: The obtained results were verified during laser doping with powder mixtures of appropriate composition on stainless steels of ferrite and ferrite-martensitic classes. Practical implications: The character of the structure formation of model alloys and the determined phase transformations in the Fe-Cr, Fe-Cr-Zr, and Fe-Cr-B-Zr systems can be used to improve the chemical composition of alloying plasters during the formation of ferrite and ferrite-martensitic stainless steel coatings. Originality/value: The model alloys were synthesized and their phase composition and microstructure were studied; also, their microhardness was measured. The influence of the chemical composition of the studied materials on the character of structure formation and their properties was analysed.

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Characterization and Oxidation Behavior of Iron-Based Coatings Prepared by Supersonic Arc Spraying at 800°C

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.697.90 ◽

2014 ◽

Vol 697 ◽

pp. 90-94 ◽

Cited By ~ 1

Author(s):

Tian Quan Liang ◽

Xian Fang Yang ◽

Yi Li Wang ◽

Cui Hua Zhao

Keyword(s):

Oxidation Resistance ◽

Oxidation Behavior ◽

Intermetallic Phase ◽

Thermal Exposure ◽

Mass Gain ◽

Arc Spraying ◽

Compact Structure ◽

Microstructure Morphology ◽

Ferric Oxides ◽

Iron Based

The characterization in microstructure, morphology and oxidation behavior of three iron-based coatings by Supersonic Arc Spraying (HVAS), were investigated by XRD, FESEM, EDS and thermal exposure in furnace in this paper. It is indicated that the three coatings are typical layer and compact structure. The coatings are composed of Fe (s.s) phase and kinds of ferric oxides, chrome carbides and/ or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements can alternate the diameter and morphologies of the holes, resulting from the formation of oxides, carbides and intermetallic phase. The results indicate that SXTiAlC coating shows the most excellent oxidation resistance with 2.70 mg·cm-2 in mass gain, while that are 88.08 mg·cm-2 and 16.64 mg·cm-2 after 100 h thermal exposure at 800°C for LX88A and SXHCrA coatings, respectively. The oxidation behavior is discussed.

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