CN108218436B - 一种降低ZrB2-SiC陶瓷材料烧结温度的方法 - Google Patents
一种降低ZrB2-SiC陶瓷材料烧结温度的方法 Download PDFInfo
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Abstract
本发明属于无机复合材料制备技术领域,涉及一种降低ZrB2‑SiC陶瓷材料烧结温度的方法。本发明添加Cr3C2可以克服在较低温度下烧结不致密和材料性能较差的问题,制备得到的ZrB2‑SiC‑Cr3C2超高温复合陶瓷致密度高、力学性能和抗氧化性能优异。在烧结ZrB2‑SiC陶瓷时添加Cr3C2,可以显著降低烧结温度。在放电等离子烧结过程中,Cr3C2与基体相发生反应,填补了陶瓷内部孔隙,增强了相间结合力,从而提高了陶瓷的致密度和力学性能。由于引入陶瓷中的Cr的氧化物在低氧压下稳定不挥发,避免了氧化时因氧化物挥发造成的氧化层疏松进而抗氧化性能差的问题,有效提高了陶瓷的抗氧化性能。
Description
技术领域
本发明属于无机复合材料制备技术领域,涉及一种降低ZrB2-SiC陶瓷材料烧结温度的方法。
背景技术
ZrB2基超高温陶瓷是高超声速空天飞行器热防护结构和防隔热功能的主导材料,是未来航空航天材料技术发展的重点方向。除此之外,ZrB2基超高温陶瓷还是熔融金属坩埚、炉电极、切削工具、裂变反应堆控制棒等方面理想的材料。因此,ZrB2基超高温陶瓷材料及其制备技术的研究对我国的航空航天事业和社会经济发展都具有非常重要的战略意义。其中, ZrB2-SiC复合陶瓷由于具有优良的烧结性能和优异的综合性能而受到了极大的关注,但是仍存在烧结致密化困难,烧结温度通常需要1900℃及以上;高温下抗氧化性能差,1200℃以上易被氧化等问题。
目前,ZrB2-SiC复合陶瓷常用的烧结方法主要有热压烧结、无压烧结、放电等离子烧结等。传统的热压烧结方法面临,材料几何形状单一、尺寸较小、运行成本高、耗时长、平行热压方向与垂直热压方向的材料性能差异大等问题。无压烧结方法面临烧结温度过高,易造成致陶瓷晶粒异常长大从而降低陶瓷的力学性能等问题。放电等离子烧结具有在较低温度下实现快速烧结致密材料的特点,不仅可以节约能源、节约时间、提高设备效率,而且所得烧结样品晶粒均匀、致密度高、力学性能好,是近些年来研究热点技术。虽然放电等离子烧结法具有诸多优势,但仍需要在超高温度下(1900-2000℃)才能达到ZrB2-SiC复合陶瓷的烧结致密化。因此,较低温度下烧结得到综合性能优异的ZrB2-SiC复合陶瓷仍是该领域研究发展的重要方向。
发明内容
本发明的目的是针对现有技术中存在的不足,克服在较低温度下烧结不致密和材料性能较差的问题,提供一种能够降低ZrB2-SiC陶瓷材料烧结温度的方法。
本发明采用的技术解决方案如下:以ZrB2、SiCt和Cr3C2为原料,采用放电等离子烧结法制备复合陶瓷,原料以体积份计,取ZrB2粉末0.7-0.8份、SiC粉末0.14-0..3份、Cr3C2粉末0.05-0.10份,粉末粒度要求为0.3~1μm,采用球磨法使原料混合均匀,球磨时以丙酮和ZrO2球为研磨介质,球磨速度为150-200rpm,球磨4-12h后干燥,过筛;采用放电等离子烧结法,在真空氛围下以100℃/min升温至烧结温度1600-1800℃,烧结压力30-40MPa,保压时间5-10min。
所述的原料以体积份计,取ZrB2粉末0.7-0.8份、SiC粉末0.14-0.23份、Cr3C2粉末0.05-0.10 份,粉末粒度要求为0.3~1μm,
所述球磨时以丙酮和ZrO2球为研磨介质,ZrO2球与原料的质量比为1-1.5:1,球磨速度为150-200rpm,球磨4-12h后干燥,过筛。
所述的放电等离子烧结是在真空氛围下以100℃/min升温至烧结温度1650-1750℃,烧结压力30-40MPa,保压时间5-10min。
本发明具有的优点和有益效果
本发明提供了一种能够降低ZrB2-SiC陶瓷材料烧结温度的方法。添加Cr3C2可以克服在较低温度下烧结不致密和材料性能较差的问题,制备得到的ZrB2-SiC-Cr3C2超高温复合陶瓷致密度高、力学性能和抗氧化性能优异。
Cr3C2是一种良好的耐磨、耐腐蚀、抗氧化的高熔点无机材料,在烧结ZrB2-SiC陶瓷时添加Cr3C2(0.05-0.10份),可以显著降低烧结温度(1600-1800℃)。使用高能球磨仪对三种粉料进行充分研磨可以达到三相分散均匀的目的。在放电等离子烧结过程中,Cr3C2与基体相发生反应,填补了陶瓷内部孔隙,增强了相间结合力,从而提高了陶瓷的致密度和力学性能。由于引入陶瓷中的Cr的氧化物在低氧压下稳定不挥发,避免了氧化时因氧化物挥发造成的氧化层疏松进而抗氧化性能差的问题,有效提高了陶瓷的抗氧化性能。
采用此技术在1600℃-1800℃下放电等离子烧结制得的ZrB2-SiC-Cr3C2陶瓷综合性能优异:致密度可达96%,室温弯曲强度可达700MPa,1500℃空气中氧化10h的氧化增重小于 10mg/cm2。本发明的应用可显著降低ZrB2-SiC陶瓷的烧结温度,提高ZrB2-SiC陶瓷的力学性能和抗氧化性能,对推动ZrB2-SiC超高温陶瓷的应用发展具有显著的社会效益和经济效益。
附图说明
图1为实施例1中烧结的ZrB2-SiC-Cr3C2陶瓷微观组织SEM图
图2为实施例2中烧结的ZrB2-SiC-Cr3C2陶瓷的XRD谱图
图3为实施例3中烧结的ZrB2-SiC-Cr3C2陶瓷的断面SEM图
具体实施方式
以下以具体实施例来说明本发明的技术方案,但本发明的保护范围不限于此。其他的任何未背离本发明所作的改变均应为等效的置换方式,都包含在本发明的保护范围之内。
一种ZrB2-SiC陶瓷材料的烧结方法,以ZrB2、SiC、Cr3C2为原料,采用放电等离子烧结法制备复合陶瓷。
以体积份计,取ZrB2粉末0.7-0.8份、SiC粉末0.14-0.3份、Cr3C2粉末0.05-0.10份,粉末粒度要求为0.3~1μm。
采用球磨法使原料混合均匀,球磨时以丙酮和ZrO2球为研磨介质,ZrO2球与原料的质量比为1-1.5:1,球磨速度为150-200rpm,球磨4-12h后干燥,过筛。
采用放电等离子烧结法,在真空氛围下以100℃/min升温至烧结温度1600-1800℃,烧结压力30-40MPa,保压时间5-10min。
实施例1
以体积份记,取ZrB2粉末0.8份、SiC粉末0.15份、Cr3C2粉末0.05份,三种粉末粒度均为0.5μm。将上述三种粉末放入球磨罐中,加入200ml丙酮和200g二氧化锆球,以200 rpm转速球磨8h,将磨好的粉料置于烘箱中干燥,随后过筛2遍。称取50g上述干燥的粉料,置于直径40mm的石墨模具中,在真空气氛下进行放电等离子烧结,以100℃/min的速度升温至1800℃,在烧结压力40MPa下保压10min。自然冷却后脱模得到ZrB2-SiC-Cr3C2陶瓷。
实施例2
以体积份记,取ZrB2粉末0.75份、SiC粉末0.15份、Cr3C2粉末0.10份,三种粉末粒度均为0.5μm。将上述三种粉末放入球磨罐中,加入200ml丙酮和200g二氧化锆球,以 200rpm转速球磨6h,将磨好的粉料置于烘箱中干燥,随后过筛2遍。称取50g上述干燥的粉料,置于直径40mm的石墨模具中,在真空气氛下进行放电等离子烧结,以100℃/min 的速度升温至1650℃,在烧结压力40MPa下保压10min。自然冷却后脱模得到 ZrB2-SiC-Cr3C2陶瓷。
实施例3
以体积份记,取ZrB2粉末0.7份、SiC粉末0.23份、Cr3C2粉末0.07份,三种粉末粒度均为0.5μm。将上述三种粉末放入球磨罐中,加入200ml丙酮和200g二氧化锆球,以200 rpm转速球磨6h,将磨好的粉料置于烘箱中干燥,随后过筛2遍。称取50g上述干燥的粉料,置于直径40mm的石墨模具中,在真空气氛下进行放电等离子烧结,以100℃/min的速度升温至1700℃,在烧结压力40MPa下保压10min。自然冷却后脱模得到ZrB2-SiC-Cr3C2陶瓷。
实施例4
以体积份记,取ZrB2粉末0.77份、SiC粉末0.15份、Cr3C2粉末0.08/份,三种粉末粒度均为0.5μm。将上述三种粉末放入球磨罐中,加入200ml丙酮和200g二氧化锆球,以200rpm转速球磨10h,将磨好的粉料置于烘箱中干燥,随后过筛2遍。称取50g上述干燥的粉料,置于直径40mm的石墨模具中,在真空气氛下进行放电等离子烧结,以100℃/min 的速度升温至1650℃,在烧结压力40MPa下保压10min。自然冷却后脱模得到 ZrB2-SiC-Cr3C2陶瓷。
实施例5
以体积份记,取ZrB2粉末0.75份、SiC粉末0.19份、Cr3C2粉末0.06份,三种粉末粒度均为0.5μm。将上述三种粉末放入球磨罐中,加入200ml丙酮和200g二氧化锆球,以 200rpm转速球磨8h,将磨好的粉料置于烘箱中干燥,随后过筛2遍。称取50g上述干燥的粉料,置于直径40mm的石墨模具中,在真空气氛下进行放电等离子烧结,以100℃/min 的速度升温至1750℃,在烧结压力40MPa下保压10min。自然冷却后脱模得到 ZrB2-SiC-Cr3C2陶瓷。
Claims (2)
1.一种ZrB2-SiC陶瓷材料的烧结方法,其特征在于:以ZrB2、SiC和Cr3C2为原料,采用放电等离子烧结法制备复合陶瓷,原料以体积份计,取ZrB2粉末0.75份、SiC粉末0.15份、Cr3C2粉末0.10份,粉末粒度要求为0.3~1μm,采用球磨法使原料混合均匀,球磨时以丙酮和ZrO2球为研磨介质,球磨速度为150-200 rpm,球磨4-12 h后干燥,过筛;采用放电等离子烧结法,在真空氛围下以100℃/min升温至烧结温度1650℃,烧结压力30-40MPa,保压时间5-10min;处理后,ZrB2-SiC陶瓷材料的室温弯曲强度可达700MPa,1500℃空气中氧化10 h的氧化增重小于10 mg/cm2。
2.根据权利要求1所述的一种ZrB2-SiC陶瓷材料的烧结方法,其特征在于:所述球磨时以丙酮和ZrO2球为研磨介质,ZrO2球与原料的质量比为1-1.5:1,球磨速度为150-200 rpm,球磨4-12 h后干燥,过筛。
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