以渗硼为主的交流电场增强粉末法硼铝共渗工艺优化

研究750 ℃时采用不同配比渗剂的以渗硼为主的交流电场增强粉末法硼铝共渗(ACFPBA)特性。通过观测分析渗层组织、相、厚度及沿层深的显微硬度分布,发现铝粉对交流电场增强粉末法硼铝共渗具有促渗作用,促渗效果不仅与渗剂中铝含量有关,还与硼铁含量有关。施加最佳铝粉量,对较低硼铁含量渗剂的促渗效果显著优于对较高硼铁含量的;对硼铁含量较低、在交流电场单一渗硼时获得Fe₂B单相渗层的渗剂,加入≥0.5%铝粉,所得渗层由FeB和Fe₂B双相组成,近表层硬度提高;在其他条件相同时,在含6%硼铁的渗剂中加入1%铝粉,经4 h电场增强共渗,得到约70 μm渗层且硬度曲线分布平缓,而相应单一渗硼的渗层厚度仅约26 μm。

Optimization of alternating current field enhanced pack boron-aluminizing boriding-based

Alternating current field enhanced pack boron-aluminizing (ACFPBA)in which the inward diffusion of boron dominated was carried out at 750 ℃ with different pack agent. By observing and analyzing the case microstructure, phase, thickness and microhardness distribution along the depth of cases, it is found that the aluminium powder in the agent can promote the ACFPBA. The promotion extent is related not only with the Al content in the agent, but also with the ferroboron content. When the optimum aluminium powder content is employed, the promotion effect with agent containing lower ferroboron content is better than that with agent containing higher ferroboron content. An ACF enhanced boriding case with Fe₂B single-phase is obtained with agent containing lower ferroboron content. However, adding more than 0.5% aluminium powder to the agent, the obtained case is composed of duplex-phase of FeB and Fe₂B. And the hardness of the near surface region is increased. When other treating parameters are the same, adding 1% aluminium powder into the agent containing 6% ferroboron leads to an about 70 μm thick case after 4 h ACFPBA and the case's hardness curve distributes more gently. However, the case thickness by corresponding ACF enhanced boriding is only about 26 μm.