| Full text | |
| Author(s): |
Ranalli, G. A.
;
Pallone, A. S. N.
;
Pereira, V. F.
;
Oliveira, R. G.
;
Mariano, N. A.
[5]
Total Authors: 5
|
| Document type: | Journal article |
| Source: | MATERIA-RIO DE JANEIRO; v. 14, n. 2, p. 814-823, 2009. |
| Field of knowledge: | Engineering - Materials and Metallurgical Engineering |
| Abstract | |
Nitriding consists of a surface hardening treatment under a nitrogen atmosphere during a certain time and temperature that may be performed by a conventional procedure (liquid or gaseous) or using plasma. The material uses in the present work was a modified type AISI H10 toll stell that has been nitrided by plasma and salt bath procedures with the objective to produce a layer with high toughness and corrosion resistant. The microstructure of the nitrided layer was characterized by scanning electron microscopy and X-ray diffraction. The layer effective depth was determined by micro-hardness profiling and the corrosion resistance was evaluated by dynamic polarization tests in an aqueous solution of sodium chloride 0,5 mol L-1 and also by testing in a salty spray camera. The microstructure obtained after the previous heat treatment of quenching and tempering consisted of a tempered martensite matrix containing a homogeneous dispersion of spherodized carbides. The nitrided layer produced by the salt bath treatment presented a diffusion layer with a depth of 150µm and an embrittled compound layer with a thickness of about 10µm. The nitrided layer created by the plasma treatment with post-oxidation presented a homogeneous compound layer with thickness of up to 7µm and a diffusion layer with a network of nitride precipitates the surfaces that were plasma nitrided with post-oxidation presented a better resistance to corrosion in aqueous 0,5 mol L-1 NaCl solution. (AU) | |