摘要
采用熔盐电解法对TC4钛合金表面渗硼以提高其表面硬度。选用硼砂和碳酸钠的混合盐作电解质,施加1.49 V电压进行渗硼实验,研究熔盐温度对渗层微观形貌及物相的影响,并对熔盐电解渗硼的反应机理进行了探讨。对不同组分的混合熔盐进行示差扫描热量(DSC)-热重(TG)分析,利用X射线衍射(XRD)仪对渗层表面及熔盐进行物相分析,利用扫描电镜(SEM)和能谱(EDS)仪分析渗层断面的形貌和元素成分。结果表明:在900℃时渗硼110 min,可获得均匀密实的渗层,主要物相是TiB_2和TiB;渗硼后试样的表面硬度为7.1 GPa;渗硼后熔盐中的主要产物是NaBO_2;渗层中先有TiB_2相生成,TiB在TiB_2相的下层形成。
A method of boriding by molten salt electrolysis was applied for TC4 titanium alloy to improve the surface hardness.The experiment was carried out with the voltage of 1.49 V,using a mixture of sodium tetraborate and sodium carbonate as the base ingredients of molten electrolyte.The effects of boriding temperature on the microstructure of the boriding layer and the reaction mechanism were studied.The mixture of sodium tetraborate and sodium carbonate with different composition was analyzed by DSC-TG.In addition,XRD was used to characterize the chemical phase of the molten salt and the borides coating;SEM and EDS were applied to observe microstructure and analyze the element content of the borides coating,respectively.Results show that a dense and uniform boriding layer is obtained on the TC4 titanium alloy with the main composition of TiB2 and TiB when the boriding temperature is 900 ℃with process duration of 110 min.The surface micro hardness of the boriding sample reaches to 7.1 GPa.Besides,NaBO2 is detected in the electrolyte after electrolysis;TiB2 is firstly produced in the boriding layer and then TiB is formed beneath it.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2016年第3期709-714,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金项目(51404186)
陕西省教育厅科研计划项目(13JS060)
