Nitriding of AISI 304 stainless steel by PIII in DC and RF toroidal discharges

Valencia, R.; López-Callejas, Régulo; Muñoz-Castro, A.E.; Barocio, S. R.; Godoy‐Cabrera, O. G.

doi:10.1590/s0103-97332004000800016

Cited by 14 publications

(6 citation statements)

References 11 publications

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“…X ray diffractions patterns for samples of AISI 304 (a) and AISI 316, (b) both untreated and nitrided at 300, 400 and 500 °C. (2) 111-200-220-311 ε-Fe 2+x N (0 < x < 1) study, the expanded austenite was considered a cubic structure since this yielded the best fitting, in agreement with literature data [14][15] . The refinement indicates an expansion on the order of 10% in unit cell volume of the austenitic structure to accommodate the N. Some authors [25][26] classified the nitrogen-expanded austenite in two types: γ N1 (paramagnetic phase with N contents 20-26 at.% N in the surface layer) and γ N2 (magnetic phase with N contents 4-10 at.% in the subsurface layer).…”

Section: Resultssupporting

confidence: 75%

“…The crystalline planes of phases γ '-Fe 4 N, ε-Fe 2+x N and CrN were indexed using Joint Committee on Powder Diffraction Standards (JCPDS) cards and the Inorganic Crystal Structure Database (ICSD). In particular the γ N -nitrogen expanded austenite was identified using literature data [14][15][16][17][18][19][20][21] . The structural characterization was performed using the Rietveld method 22 and the crystal structure of each phase was obtained using FullProf-suite software 23 .…”

Section: Introductionmentioning

confidence: 99%

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A comparative study of mechanical and tribological properties of AISI-304 and AISI-316 submitted to glow discharge nitriding

Nascimento¹,

Foerster²,

Silva³

et al. 2009

Mat. Res.

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cannot be applied. The mechanical response for external loads is then better simulated by instrumented indentation performed on ion beam modified surfaces rather than on cross-sections.In the present work we report a comparative study about structural, mechanical and tribological properties of AISI 304 and AISI 316 stainless steels submitted to nitrogen glow discharge at different substrate temperatures from 300 to 500 °C. Structural characterization was evaluated by X ray diffraction (Bragg-Brentano geometry) using Rietveld refinement. Hardness, elastic modulus profiles and surface topography were obtained by instrumented indentation. Conventional Vickers measurements were also employed in order to obtain deeper hardness profiles. Tribological and wear behavior were studied by reciprocating sliding tests. Experimental ProcedureCommercial sheets of AISI 304 (Ni 8.63%, Cr 16.04%, C 0.047%, Si 0.48%, Mn 1.37%, S 0.005%, Mo 0.09%, P 0.029% weight, with Fe being the balance) and commercial rods of AISI 316 (Ni 11.64%, Cr 15.68%, C 0.10%, Si 0.34%, Mn 1.73%, S 0.031%, Mo 1.86%, P 0.029% weight with Fe being the balance) were cut in 1.5 x 1.5 x 0.5 cm and φ = 3 cm and 0.5 cm thick pieces, respectively. The samples were mechanically polished up to ¼ µm diamond paste in order to obtain a final mirror finish.DC glow discharge was performed in N 2 :H 2 -20:80 atmosphere at 600 Pa with prior H 2 sputtering at 100 °C during 2 hours. The plasma current ranged from 200 to 300 mA, resulting in sample ensembles with substrate temperatures of 300, 400 and 500 °C. The temperature was controlled by monitoring a backside thermocouple and adjusting the plasma current as needed. All samples were nitrided during four hours. Mechanical and tribological properties of AISI 304 and AISI 316 stainless steels submitted to glow discharge ion nitriding are reported. The atmosphere was 20:80 -N 2 :H 2 with substrate temperatures ranging from 300 to 500 °C. Treatment at 300 °C produced expanded austenite (γ N ) in both steels. Increasing the temperature, the phases γ′-Fe 4 N and ε-Fe 2+x N were present and the latter is the major phase for AISI 304. At 500 °C, the CrN phase was also identified in both steels. Hardnesses of about 13-14 GPa at near surface regions were obtained in both steels. Moreover, AISI 316 nitrided at 500 °C has the deepest hard layer. Tribological tests showed that wear can be reduced by up to a factor of six after the nitriding processes, even for a working temperature of 300 °C. The profiles during and after nanoscratch tests did not reveal significant differences after nitriding processes in both steels.

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Section: Resultssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

A comparative study of mechanical and tribological properties of AISI-304 and AISI-316 submitted to glow discharge nitriding

Nascimento¹,

Foerster²,

Silva³

et al. 2009

Mat. Res.

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“…However, the high temperature used in conventional nitriding process is not adequate to treat stainless steel (SS), due to the deleterious effect to its corrosion behavior [2,3]. Temperatures in excess of 480 0 C during nitriding in SS cause precipitation of chromium nitride [4], albeit they are mandatory in this case to the achievement of enhanced mechanical and tribological properties.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of austenitic stainless steel nitrided in a hybrid glow discharge plasma

Oliveira¹,

Ueda²,

Silva³

et al. 2009

Braz. J. Phys.

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A nitriding process based on two distinct nitrogen glow discharge modes, with sample temperatures ranging from 380 0 C to 480 0 C, was employed to treat the surface of austenitic stainless steel (SS 304). The temperature is controlled exclusively by switching the operation conditions of the discharges. First mode of operation is the conventional one, named cathodic, which runs at higher pressure values (1 mbar) in comparison to the second mode, named anodic, which runs at the pressure range of 10 −3 − 10 −2 mbar. Cathodic mode is used to quickly heat the sample holder, by the high ion flux. On the other hand, in the anodic mode, due to the lower operation pressure, higher effective ion acceleration takes place, which allows deeper ion implantation into the sample surface. This hybrid process was thoroughly explored regarding the duty cycle and conditions of operation, to achieve optimal performance of the treatments, which led to the attainment of surface hardness for samples of AISI SS 304 as high as 20 GPa and improvements including higher elastic modulus and resistance against corrosion. Detailed comparison among samples treated by this process with others treated by conventional method was done using nanoindentation, Auger Electron Spectroscopy (AES) and corrosion resistance testing.

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“…Electric discharges in gases carried out for several processes, such as those related with surface modification, demand plasma particle densities as high as possible as these are determinant to improve the treatment life time [1] and the general process efficiency [2].…”

Section: Introductionmentioning

confidence: 99%

V-I curves and plasma parameters in a high density DC glow discharge generated by a current-source

Granda‐Gutiérrez

López-Callejas

Peña‐Eguiluz

et al. 2008

J. Phys.: Conf. Ser.

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Nitriding of AISI 304 stainless steel by PIII in DC and RF toroidal discharges

Cited by 14 publications

References 11 publications

A comparative study of mechanical and tribological properties of AISI-304 and AISI-316 submitted to glow discharge nitriding

A comparative study of mechanical and tribological properties of AISI-304 and AISI-316 submitted to glow discharge nitriding

Characteristics of austenitic stainless steel nitrided in a hybrid glow discharge plasma

V-I curves and plasma parameters in a high density DC glow discharge generated by a current-source

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