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目的：研究基于缝式喷嘴的SiCl4和N2混合气体的喷射工艺参数对CVD法制备6.5%Si钢渗硅速率的影响。方法采用不同的反应温度、SiCl4气体体积分数、混合气体流量进行渗硅实验,通过扫描电镜、能谱分析、失重比研究这3个参数对渗硅速率的影响,并对比分析喷嘴喷射反应气体和均匀气氛对渗硅速率的影响。结果缝式喷嘴喷射反应气体能极大提升渗硅速率。随着温度的升高,渗硅速率不断升高,达到1100℃后,渗硅速率趋于饱和不再有明显变化。随着SiCl4气体体积分数和混合气体流量的升高,渗硅速率均先升高,再逐渐降低,当SiCl4气体体积分数为15%时,渗硅速率达到最大；当混合气体流量为1 L/min时,渗硅速率达到峰值。结论 CVD法制备6.5%Si钢时,采用缝式喷嘴喷射反应气体具有明显的优势,最佳工艺参数为：反应温度1170℃,SiCl4气体体积分数15%,混合气体流量1 L/min。

Objective To investigate the influence of the SiCl4 and N2 mixture ejection parameter by using a slot nozzle on the siliconizing rate during the preparation of 6. 5%Si steel by CVD method. Methods The siliconizing experiment was conducted at different reaction temperatures, volume fractions of SiCl4 gas, and mixture gas flows. The impact of these factors on the siliconizing rate was analyzed by scanning electron microscope, energy spectrum analysis and weightlessness ratio analysis. And the comparison of siliconizing rates under ejection by slot nozzle and uniform atmosphere was conducted. Results The siliconizing rate was signifi-cantly improved by the application of slot nozzle. The siliconizing rate continuously increased with increasing temperature. After the temperature reached 1100 ℃, the siliconizing rate tended to saturate and did not show obvious change with further increase of the temperature. And the siliconizing rate increased firstly and then gradually decreased with the increase of SiCl4 concentrations and mixture gas flows, when the concentration of SiCl4 was 15%, the siliconizing rate reached the maximum; when the gas flow rate was 1 L/min, the siliconizing rate reached the peak value. Conclusions There was a great advantage by using slot nozzle to inject reaction gas in the preparation of 6. 5%Si steel with CVD method. Moreover, the siliconizing rate was the highest when the reaction temperature was 1170 ℃, SiCl4 gas volume fraction was 15%, and gas mixture flow was 1 L/min.