碳钢浸镀扩散渗铝复合渗硼及其表面性能研究  

Hot-dip Aluminizing and Subsequent Boronizing for the Plain Carbon Steels and Performances of the Aluminoboronized Layers

作　　者：罗新民[1] 李殿凯[1] 王兰[1] 陈康敏[1] 

机构地区：[1]江苏大学材料科学与工程学院,镇江212013

出　　处：《热处理》2005年第2期20-25,共6页Heat Treatment

摘　　要：对Q235、45、GCr15钢在720℃±5℃的条件下进行了热浸渗铝,分别扩散1h、2.5h和5h后再进行950℃×6h高温渗硼。利用光学显微镜、扫描电镜、X射线等手段研究了Q235、45钢的热浸渗铝和热浸渗铝复合渗硼层的组织结构。探讨了热浸扩散渗铝复合渗硼中的硼化物的形成机理及硼的迁移机制。采用高温氧化试验和耐热腐蚀试验考察了这两种渗层在高温下的氧化机制,并比较了它们的耐高温氧化性能和耐热腐蚀性能,以及它们在干摩擦条件下的耐磨性。试验结果表明,热浸渗铝经扩散处理后,渗层明显,渗层组织由表及里出现了η相(Fe2Al5)、β1相(Fe3Al)和α相固溶体等组织。热浸渗铝复合渗硼所形成渗层具有与单一渗硼相类似的齿状形态。X射线衍射分析表明,渗层主要由Fe2B、Fe2AlB2及Fe2Al5组成。Q235钢热浸镀铝复合渗硼处理在950℃高温下不具有明显的抗氧化的作用。而热浸渗铝的Q235钢950℃氧化后仍然为扩散处理后的灰色外观。而650℃循环氧化中,这两种渗层的抗氧化能力相当。800℃熔盐腐蚀试验中热浸渗铝与热浸渗铝复合渗硼处理均具有较高的耐蚀胜,比未经处理的试样高10倍左右。在干摩擦条件下,热浸渗铝复合渗硼试样比渗铝扩散处理具有更高的耐磨性。Q235, 45 and GCr15 steels were dipped in molten aluminum bath at 725±5℃ and diffused for 1, 2.5 and 6h respectively and then boronized at 950℃ for 6h. The structures of surface layer of Q 235 and 45 steels hot-dip aluminized and hot-dip aluminized and subsequently boronized were investigated by means of optical microscope, SEM and XRD. The mechanism of both forming boride and transferring of boron in the aluminized and then boromized layer were discussed. The mechanism of oxidation at high temperature, resistance to elevated temperature oxidation and to thermal erosion as well as wear resistance under dry friction for the two type of surface layers were investigated. The tested results show that the hot-dip aluminized layer is composed of the η-phase (Fe 2 Al 5 ), β 1 -phase (F 3 Al) and α-phse from surface to matrix. The microstructure of the aluminized and Subsequently boronized Layer is similar to that of simply boronized Layer and is tooth-like. The XRD spectrum shows that the aluminized and subsequently boronized layer consists of chiefly Fe 2 B, Fe 2 AlB 2 and Fe 2 Al 5 . The oxidation resistance at 950℃ of the aluminized and subsequently boronized Q235 steel is not obvious. Q235 steel hot-dip aluminized and oxidated at 950℃ appears as grey, being similar to as -aluminized colour. The two tye of surface Layers are about the same in the oxidation resistaence during the circle oxidating at 650℃. The both hot-dip aluminized and aluminized and subsequently boronized layers have all better corrosion resistance during corrosion test in fused salt at 800℃, and are ten times over that of untreated surface. Under dry friction condition, the wear resistance of the aluminized and subsequently boronized sample is better than that of aluminized sample.

关 键 词：热浸渗铝 复合渗硼 氧化 热腐蚀 磨损 

分 类 号：TG156.8[金属学及工艺—热处理] 6[金属学及工艺—金属学] TG156.87