The effect of pulse width on the microstructure of d.c.-plasma-nitrided layers

[摘要] Modern ion nitriding equipment are powered by pulsed sources in order to prevent arcing and overheating. In industrial applications, the pulse frequency is usually adjusted to set the working temperature. However, frequency variations may drastically affect the plasma species population, and consequently, the microstructure of the final nitrided layer. In this study, AISI-409 steel was nitrided in a mixture of 20% N-2-80% H-2 using a d.c power source. The depth and microstructure of the nitrided layer were assessed as a function of the time that the voltage was off, t(off), in the range of 1-4 ms during a 10 ms pulse cycle. The results suggested that both the microstructure and mechanical behavior of the nitrided layer were affected by t(off). Long t(off) values imply a deleterious effect on the mechanical properties of the nitrided layers. (C) 1999 Elsevier Science S.A. All rights reserved.

[发布日期] 1999-12-15

[关键词] ion bombardment;plasma nitriding;pulsed plasma