Study of the nitrided layer obtained by different nitriding methods

Elisangela Aparecida Dos Santos De Almeida,Júlio César Giubilei Milan,César Edil Da Costa

doi:10.1590/s1517-707620150002.0046

Elisangela Aparecida Dos Santos De Almeida, Júlio César Giubilei Milan + Show 1 more

Open Access

https://doi.org/10.1590/s1517-707620150002.0046

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Abstract

In this study, plasma nitriding, gas nitriding and solid nitriding were performed in AISI H13, AISI P20 and N-8550 tool steels. The aim of the study was compare the acquired properties after the thermochemical treatments and evaluate the efficiency of the solid nitriding treatment. The samples were analyzed using a microhardness tester and a scanning electron microscope. The typical nitriding layers were observed - white layer and diffusion layer. The phases Fe4N - γ´ and Fe2,3N - e were identified using an X- Ray diffractometer. The microhardness values of the nitrided layers obtained by the solid nitriding treatment were compatible with the other values of microhardness obtained by plasma and gas nitriding. The thickness of the nitrided layer obtained by the solid nitriding treatment was irregular.

Highlights

Nitriding is a thermochemical treatment that consists in the introduction of nitrogen into metallic material
Gas nitriding is promoted by holding the metal at a suitable temperature, submitting the samples to a gas atmosphere that contains nitrogen, normally ammonia [3]
Ion/plasma nitriding uses a glow discharge to introduce nitrogen into the metallic material. For this process it is important that the samples are in a vacuum environment, so that the nitrogen ions can be accelerated and impinge the steel surface diffusing into it [4, 5]

Summary

INTRODUCTION

Nitriding is a thermochemical treatment that consists in the introduction of nitrogen into metallic material. Ion/plasma nitriding uses a glow discharge to introduce nitrogen into the metallic material. For this process it is important that the samples are in a vacuum environment, so that the nitrogen ions can be accelerated and impinge the steel surface diffusing into it [4, 5]. Plasma nitriding treatment promotes greater control of different treatment parameters and this enables a higher reproducibility of results and allows the control of the microstructure of the nitrided layer [18]. Solid nitriding consists in promote the diffusion of nitrogen into the metallic material using a Fe4KCN granulated (Turbonit k20®), and the process needs only a muffle oven to promote the heating. An X-ray diffractometer identified the phases formed in the three treatments

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS

AKNOWLEDGEMENTS