论文部分内容阅读
本文对两种类型(B_4C型和B-Fe型)渗硼剂采用气相色谱、原子吸收、火焰光度、氟离子电极、X射线衍射、光谱分析和元素分析等方法确定了渗硼过程中所形成的气态产物和渗硼前后渗剂中存在的各物质成分,并通过热力学计算,推导出渗硼过程的化学反应,从而对渗硼时硼化物的形成和成长提出可靠依据。我们采用常温及高温X射线衍射、电镜、电子探针等手段,研究渗硼层的相结构、形成机理与相变,得到如下结果:1.渗硼层的形成是一种成核成长过程。2.渗硼层中存在M_3(C.B)型的熔化物相(其中M为Cr、Mn或Fe),呈颗粒状弥散分布。3.具有双相渗硼层的45钢、GCr15钢经900℃、4小时、10~(-2)mmHg真空退火后,FeB区减少,总厚度增加。4.利用高温X射线衍射,测得FeB的德拜温度(?)在温度为900°～1100°K之间的平均实验值为2400°K,由准弹性结合常数γ=4π~2mk(?)~2/h说明了要使FeB转变为Fe_2B的温度是很高的,不易进行。
In this paper, two types of boronizing agents (B_4C and B-Fe) were determined by gas chromatography, atomic absorption, flame photometry, fluoride ion electrode, X-ray diffraction, spectral analysis and elemental analysis And the composition of each substance existing in the seepage agent before and after boronizing, and through the thermodynamic calculation, the chemical reaction of the boronizing process is deduced to provide a reliable basis for the formation and growth of the boride during boronizing. The phase structure, formation mechanism and phase transition of boronizing layer were studied by means of X-ray diffraction, electron microscope and electron probe at room temperature and high temperature. The results are as follows: 1. The formation of boronizing layer is a nucleation and growth process. 2. There is M_3 (C.B) -type melt phase (where M is Cr, Mn or Fe) in the boronizing layer, and there is a granular dispersion. In the 45 steel and GCr15 steel with dual-phase infiltrated layer, the FeB zone decreases and the total thickness increases after vacuum annealing at 900 ℃ for 4 hours and 10 ~ (-2) mmHg. 4. Using high-temperature X-ray diffraction, the Debye temperature (?) Of FeB measured at an average temperature of 900 ° ~ 1100 ° K of 2400 ° K, the quasi-elastic binding constant γ = 4π ~ 2mk (? ) ~ 2 / h shows that the temperature at which FeB is converted to Fe_2B is high and not easy to carry out.