Decarburization during plasma nitriding

Egert, Paola; Maliska, A.M.; Silva, H.R.T.; Speller, C. V.

doi:10.1016/s0257-8972(99)00407-7

Cited by 14 publications

(8 citation statements)

References 4 publications

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“…Therefore, as the microstructures presented show good sintering of titanium at the temperatures at which the samples were processed, it is believed that the residual oxygen in the mix is consumed in the plasma, with no increase in the formation of oxides on the surface of the particles. This effect was confirmed by Egert 17 in his study on the nitriding of iron samples by plasma. In his work, Egert investigated the influence of O 2 in the process with the mass spectrometry technique.…”

Section: Analysis Of the Sintered Samplesmentioning

confidence: 53%

Sintering unalloyed titanium in DC electrical abnormal glow discharge

et al. 2010

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Powder metallurgy is widely used in the manufacture of components that have complex geometry. The good dimensional control, reduction in manufacturing steps and operating costs which has favored the use of this technique for manufacturing of titanium alloys components. However, the high affinity of this material with oxygen hinders strongly the sintering process. For this, the sintering associated with plasma technology can be considered an alternative technique for the processing of this material. The strict control of sintering atmosphere performed at low pressures and the reactive species present in the plasma environment can help to improve the sintering of this material. The results presented in this paper show a good correlation between the parameters used for the compaction of the samples and the microstructure develop during the plasma sintering of samples. The microstructure of the plasma assisted samples is also affected by the particular configuration used in the plasma reactor.

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Section: Analysis Of the Sintered Samplesmentioning

confidence: 53%

Sintering unalloyed titanium in DC electrical abnormal glow discharge

et al. 2010

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“…Alguns estudos (18,20,21) sobre a nitretação a plasma de aços indicam a ocorrência da descarbonetação como resultado da interação da superfície do material com o plasma. Na superfície da amostra, o carbono é arrancado e reage com os íons positivos de hidrogênio formando hidrocarbonetos.…”

Section: Espectroscopia óPtica Em Descarga Incandescente (Gdos)unclassified

“…Contudo, diversos estudos (18,20,21) apresentam resultados consistentes indicando que, durante a nitretação a plasma de aços, o carbono difunde-se à frente da interface nitretada, conduzindo à formação de uma zona rica em carbono.…”

Section: Espectroscopia óPtica Em Descarga Incandescente (Gdos)unclassified

Estudo Do Perfil De Carbono Na Camada Nitretada Do Aço Aisi M2

Tier

Kieckow

Strohaecker

et al. 2007

TMM

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ResumoO principal objetivo deste trabalho é investigar a redistribuição do carbono que normalmente se observa após a nitretação a plasma de aços. Amostras do aço AISI M2 foram nitretadas em um reator a plasma com 60 kW, variando-se temperatura, tempo e composição do gás de tratamento. Foram realizadas análises de difração de raios X, espectroscopia de emissão óptica em descarga incandescente -GDOS e microscopia óptica e eletrônica de varredura. De acordo com as análises GDOS, as amostras nitretadas apresentaram descarbonetação na superfície da camada nitretada, e enriquecimento de carbono na região de interface da camada com o substrato. Para algumas condições de tratamento, foi observada a existência de um pequeno pico de carbono na interface entre a camada de compostos e a zona de difusão. Os resultados obtidos sugerem que a camada de compostos atue como uma barreira para a descarbonetação. Observa-se que, em amostras com camada de compostos bem definidas, o nível de descar bonetação foi baixo resultando em uma significativa precipitação de carbetos em contornos de grão. Palavras-chave: Nitretação a plasma; Camada nitretada; Descarbonetação. A STUDY OF CARBON PROFILE IN THE NITRIDED LAYER OF AISI M2 STEEL AbstractThe aim of this work is to investigate the redistribution of carbon normally observed after plasma nitriding of steels. Samples of AISI M2 steel were plasma nitrided in a 60 kW reactor varying temperature, time, and treatment gas composition. X-ray diffraction, glow discharge optical spectroscopy -GDOS, optical and scanning electron microscopy analysis were performed. According to GDOS analysis, the samples presented decarburization on the surface of the nitrided layer and a carbon enrichment zone in the interface layer-substrate. For some conditions of treatment, it was observed the presence of a small peak of carbon in the interface between the compound layer and the diffusion zone. The results suggest that the compound layer works as a barrier for the decarburization process. It was observed that for samples with a compact compound layer, the level of decarburization was low which resulted in a high level of carbides precipitation in the grain boundaries.

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“…(1) takes into account the onset time of the nitriding process, and t is the treatment time. The temperature dependence of the effective diffusion coefficient (Dk) can be approximately expressed in an Arrhenius form [14][15][16]:…”

Section: Introductionmentioning

confidence: 99%

Diffusion Layer Growth Mechanism in ASPN Method Using an Iron Cage for St52 Steel

Salavat¹,

Soltanieh²,

Niasari³

2016

World Congress on Mechanical, Chemical, and Material Engineering

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The mechanism of diffusion layer growth in plasma nitrided coatings applied on a St52 steel using an active screen is investigated. The nitriding was performed at 450, 500 and 550 •C temperature nitriding times of 5, 10 and 15 h, in a gas mixture containing 20 vol. % H2: 80 vol. % N2 and DC-pulsed plasma nitriding unit. The surface, cross section and the thickness of diffusion of specimens was studied in terms of optical and scanning electron microscopy. According to the measurements of diffusion layer thickness, values of Q and Do for nitrogen diffusion in substrate were calculated as 50585 (J/mol) and 4.11×10-10 (m 2 /s), respectively. The variations of hardness depth during nitriding period were determined.

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Decarburization during plasma nitriding

Cited by 14 publications

References 4 publications

Sintering unalloyed titanium in DC electrical abnormal glow discharge

Sintering unalloyed titanium in DC electrical abnormal glow discharge

Estudo Do Perfil De Carbono Na Camada Nitretada Do Aço Aisi M2

Diffusion Layer Growth Mechanism in ASPN Method Using an Iron Cage for St52 Steel

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