结合剂种类对刚玉-尖晶石浇注料抗镍基高温合金侵蚀性能的影响

Effect of binder type on corrosion resistance to nickel-based superalloy of corundum-spinel castables

为扩展刚玉-尖晶石材料在高温合金冶炼方面的应用,以电熔白刚玉(粒度为5~3、3~1、≤1和≤0.074 mm)和烧结尖晶石(粒度≤1、≤0.044 mm)为主要原料,活性α-Al_(2)O_(3)微粉为烧结助剂,分别以Secar 71水泥、ρ-Al_(2)O_(3)微粉和磷酸镁水泥作为结合剂,制备了刚玉-尖晶石条形试样和坩埚试样,探究了不同结合剂对刚玉-尖晶石质浇注料常规性能和抗镍基高温合金侵蚀性能的影响。结果表明:1)3种结合剂中,采用Secar 71水泥作为结合剂的条形试样常规性能较好,1600℃烧后线收缩率最低,抗侵蚀试验后坩埚试样宏观侵蚀渗透面积最小,微观渗透深度最浅,抗镍基高温合金侵蚀性能最好。2)镍基高温合金中的Cr渗透进入坩埚内部较浅,Nb、Ti渗透明显比Cr更深,而主成分Ni、Fe几乎没有渗透进入坩埚试样内部。

In order to expand the application of corundum-spinel materials in superalloy smelting,corundum-spinel strip specimens and crucible specimens were prepared using white fused corundum with particle sizes of 5-3,3-1,≤1 and≤0.074 mm and sintered spinel with particle sizes of≤1 and≤0.044 mm as the main raw materials,activeα-Al_(2)O_(3)micropowder as the sintering aid,Secar 71 cement,ρ-Al_(2)O_(3)micropowder or magnesium phosphate cement as the binder.The effects of different binders on the conventional properties and corrosion resistance to nickel-based superalloy of the specimens were researched.Among the three kinds of binders,the strip specimen with Secar 71 cement as the binder has optimal conventional performance and the lowest linear shrinkage rate after firing at 1600℃.After the corrosion resistance test,the crucible specimen with Secar 71 cement as binder has the smallest macroscopic corrosion penetration area,the shallowest microscopic penetration depth,and the best corrosion resistance to nickel-based superalloy.The penetration of Cr into the crucible is shallow,and the penetration of Nb and Ti is obviously deeper than that of Cr,while the main components Ni and Fe hardly penetrate into the crucible specimens.