Cojocaru Mihai Ovidiu, Branzei Mihai, Ghinea Andrei Mihai, Druga Leontin Nicolae
Department of Metallic Materials Science, Physical Metallurgy, Faculty of Materials Science and Engineering, University POLITEHNICA of Bucharest, 060042 Bucharest, Romania.
Section IX-Materials Science and Engineering, Technical Sciences Academy of Romania, 030167 Bucharest, Romania.
Materials (Basel). 2021 May 7;14(9):2432. doi: 10.3390/ma14092432.
This paper discusses the issue of the effects of modifying the activity of nitriding media by diluting ammonia with nitrogen and the concomitant variation in the degree of ammonia dissociation on the layer's growth kinetics and their phase composition. To understand and quantify the effects of the variation in the main parameters that influence the layer growth kinetics, the experimental programming method was used and mathematical models of interactions between influence and kinetics parameters were obtained for two metallic materials: Fe-ARMCO and 34CrAlMo5 nitralloy steel. It was concluded that the nitriding operating temperature and the degree of nitrogen dilution of the ammonia have statistically significant influences on the kinetics of the nitrided layer. In the same context, it was analytically proved and experimentally confirmed that the ammonia degree dissociation from the gaseous ammonia-nitrogen mixture, along with the dilution degree of the medium with nitrogen, significantly influences the nitrogen potential of the gaseous mixture used for nitriding and thus the concentration of nitrogen in balance at the medium thermochemically processed metal product interface.
本文讨论了用氮气稀释氨气来改变渗氮介质活性以及随之而来的氨解离度变化对渗层生长动力学及其相组成的影响问题。为了理解和量化影响渗层生长动力学的主要参数变化的影响，采用了实验编程方法，并针对两种金属材料（Fe-ARMCO和34CrAlMo5氮化合金钢）获得了影响参数与动力学参数之间相互作用的数学模型。得出的结论是，渗氮操作温度和氨气的氮稀释度对渗氮层的动力学有统计学上的显著影响。在同样的情况下，经分析证明并通过实验证实，气态氨-氮混合物中的氨解离度以及介质的氮稀释度，会显著影响用于渗氮的气态混合物的氮势，从而影响在经过热化学处理的金属产品界面处介质中处于平衡状态的氮浓度。
