Plasma Carburizing of Sintered Pure Iron at Low Temperature

Thiago De Souza Lamim,Euclides Alexandre Bernardelli,Aloisio Nelmo Klein,Ana Maria Maliska,Cristiano Binder

doi:10.1590/1516-1439.306514

Thiago De Souza Lamim, Euclides Alexandre Bernardelli + Show 3 more

Open Access

https://doi.org/10.1590/1516-1439.306514

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Journal: Materials Research	Publication Date: Apr 1, 2015
Citations: 8	License type: cc-by

Affiliation: Universidade Federal de Santa Catarina

Abstract

In this work, plasma carburizing of sintered pure iron at low temperature was investigated. Samples were carburized under a dc abnormal glow discharge in two mixed atmospheres (5%CH4 + 95%H2 and 20%CH4 + 80%H2) at 500 °C and 700 °C for 3 and 6 hours. The influence of these parameters was investigated by Scan Electron Microscopy (SEM), X-ray Diffraction (DRX), Raman spectroscopy and microhardness measurements. There is a correlation between temperature and layer morphology, and a layer of polycrystalline cementite was obtained at 500 °C and 700 °C on a ferrite substrate. Furthermore, the carburized layer thickness increased with an increase in the treatment time and the methane percentage. The topography is very dependent on the treatment temperature.

Highlights

The use of surface treatments by plasma technology has increased substantially in recent years, and this technique is used to improve the surface properties of different materials and to optimize their applications[1,2,3,4,5].Among the diverse plasma surface treatments, carburizing has yielded good results in different applications[6,7,8,9]
This work was performed to examine the formation of a cementite layer during plasma carburizing at low temperatures (500 °C and 700 °C) in sintered unalloyed iron
Carburizing at 500 °C promotes the formation of a thin and continuous cementite layer along the entire surface, which should be associated with the low diffusivity and solubility of the carbon into α-Fe at this temperature

Summary

Introduction

The use of surface treatments by plasma technology has increased substantially in recent years, and this technique is used to improve the surface properties of different materials and to optimize their applications[1,2,3,4,5].Among the diverse plasma surface treatments, carburizing has yielded good results in different applications[6,7,8,9]. The interest in applying plasma carburizing at low temperatures is to combine the known advantages[2,10] of this technology with the possibility of achieving better dimensional control of pieces with complex geometry[11]. This technique was found to be an efficient technique in the hardening process of austenitic[12,13] and martensitic[14,15] stainless steel due to the sensitization phenomenon above 450 °C in these materials. There are some studies in the literature, which use plasma carburizing at low temperature as a useful method to produce surface layers of pure cementite[16,17,18,19]

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