Nitriding and Sintering Mechanisms of 12%Cr Ferritic Stainless Steel Powder Compacts in Nitrogen Atmosphere
Nitriding and Sintering Mechanisms of 12%Cr Ferritic Stainless Steel Powder Compacts in Nitrogen Atmosphere
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氮化%20and%20烧结%20机制%20of%2012%Cr%20铁素体%20不锈钢%20钢%20粉末%20压坯%20in%20氮%20大气
DOI：
10.2355/tetsutohagane1955.79.10_1204
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Y. Tokunaga
中科院分区：
文献类型：
--
作者：
N. Nakamura;S. Takaki;M. Kamada;Y. Tokunaga
摘要：用光学显微镜和化学分析方法研究了12质量%铬铁素体不锈钢(SUS410L)粉末压坯在氮气气氛中的烧结和氮化行为。从氮气在奥氏体晶内和晶界扩散的角度讨论了渗氮奥氏体化的动力学。结果表明：(1)在氮气气氛中，在1473K的烧结温度下，钢粉在加热到烧结温度时，约有0.26%的氮通过气孔被吸收，铁素体相因氮的吸附而转变为奥氏体。因此，在1473K时，烧结是以奥氏体态进行的，经过烧结处理后，奥氏体相变为马氏体，冷却到室温。(2)粉末颗粒内的晶界起到了氮气扩散的自由通道作用，因此铁氧体粉末颗粒的渗氮奥氏体化不仅从颗粒表面开始，而且从每个粉末颗粒内的晶界开始。(3)氮化速度很大程度上取决于粉末颗粒内部的颗粒尺寸，但当颗粒为单晶时，氮化速率取决于颗粒本身的尺寸。随着粉末颗粒内颗粒尺寸的减小，渗氮速率增大。
Synopsis : Sintering and nitriding behaviors of 12mass%Cr ferritic stainless steel (SUS410L) powder compacts in nitrogen gas atmosphere were investigated by means of optical microscopy and chemical analysis. Kinetics of the austenitization by nitriding was also discussed in terms of nitrogen diffusion within austenite grain and along grain boundaries. The results obtained are as follows : ( 1 ) At sintering temperature of 1473K in nitrogen gas atmosphere, about 0.26mass% of nitrogen is absorbed into the steel powders through open pores during heating to the sintering temperature, and ferritic phase changes to austenite owing to nitrogen absorption. Therefore, sintering proceeds in the state of austenitic structure at 1473K and then austenite transforms to martensite on cooling to room temperature after the sintering treatment. ( 2 ) Grain boundaries within powder particles play a role of free path for nitrogen diffusion, so that the austenitization by nitriding in ferrite powder particles proceeds not only from the particle surface but also from grain boundaries within each powder particle. ( 3 ) Nitriding rate greatly depends on the grain size within powder particles, although it is dependent on particle size itself when particles are of single crystal. As the grain size within powder particles becomes smaller , nitriding rate is increased.