不同粘结剂对立方氮化硼复合材料性能影响的研究

发布时间：2018-04-11 02:16

  本文选题：超硬材料 + 立方氮化硼　； 参考：《山东大学》2017年硕士论文

【摘要】：立方氮化硼(cBN)是一种硬度仅次于金刚石的材料,具有优异的机械、电学、光学和热学性能,在各种高新科技领域具有重要的研究和应用价值。聚晶立方氮化硼(PcBN)以cBN单晶为主要原材料,在高温高压下烧结而成,是一种应用广泛的刀具材料。在PcBN的烧结过程中,粘结剂作为一个重要的影响因素,与cBN单晶相互作用,对PcBN的性能有很大影响,具有重要的研究价值。合成PcBN的粘结剂有很多种,主要包括金属粘结剂,陶瓷粘结剂以及一些其它粘结剂。本文选取了较为常见的金属铝(Al)和陶瓷碳化钛(TiC),以及新型三元过渡族金属碳化物钛碳化硅(Ti3SiC2)和钛碳化铝(Ti3AlC2)分别作为粘结剂材料用来合成PcBN块体材料。分析研究了 PcBN的成分、抗弯强度、抗压强度、硬度以及热稳定性。研究发现,当以Al作为粘结剂时,Al会与cBN在高温高压下发生反应,生成AlN和AlB2等物质。随着Al的添加量从5 wt.%增加到10 wt.%,后增加至20 wt.%,所合成的PcBN的抗弯强度和抗压强度表现出先降低,后增大的趋势。烧结过程中所产生的AlN和AlB2对整体PcBN有粘结作用,同时也是断裂容易发生的地方。而当TiC作为粘结剂时,由于TiC惰性强,熔点高,TiC和cBN之间并未发生反应,所合成的PcBN仍然由cBN和TiC组成。添加10 wt.%的TiC可使合成的最致密的结构,同时可使烧结得到的PcBN具有较好的机械性能。当以Ti3AlC2或Ti3SiC2作为粘结剂在高温高压下烧结PcBN时,在烧结过程,Ti3AlC2或Ti3SiC2会分解并与cBN发生反应,并最终生成TiC,TiC0.7N0.3,TiB2,SiC以及AlN等物质。对于cBN-Ti3AlC2烧结组来说,当添加20 wt.%Ti3AlC2时,烧结出的PcBN具有最致密的结构,同时具有最高的抗弯强度、抗压强度以及硬度。而当以Ti3SiC2为粘结剂时,当添加10wt.%Ti3SiC2时,烧结出的PcBN具有最高的抗弯强度;添加20wt.%Ti3SiC2时,PcBN具有最高的抗压强度;而添加40 wt.%Ti3SiC2时,PcBN具有最高的硬度和最致密的结构。对于这四种粘结剂所合成的PcBN,各取一个试样进行热分析,并且分析了氧化后的表面成分。氧化过后,PcBN表面会形成Al和Ti等的氧化物层,并伴随着裂纹的出现。尽管氧化层不够致密,但能对PcBN材料内部起到一定的保护作用。
[Abstract]:Cubic boron nitride (CBN) is a kind of material whose hardness is second only to diamond. It has excellent mechanical, electrical, optical and thermal properties, and has important research and application value in various high-tech fields.Polycrystalline cubic boron nitride (PcBN) is a widely used tool material, which is sintered at high temperature and high pressure using cBN single crystal as the main raw material.In the sintering process of PcBN, the interaction between binder and cBN single crystal, as an important influence factor, has great influence on the properties of PcBN and has important research value.There are many kinds of binders for the synthesis of PcBN, including metal binders, ceramic binders and some other binders.In this paper, the more common metal Al) and the ceramic titanium carbide TiCX, as well as the new ternary transition metal carbides Ti3SiC2) and the Ti3AlC2Ti3AlC2) are used as binders to synthesize PcBN bulk materials, respectively.The composition, bending strength, compressive strength, hardness and thermal stability of PcBN were studied.It is found that when Al is used as binder, Al can react with cBN at high temperature and high pressure to form AlN and AlB2.With the increase of Al content from 5wt.% to 10wt.and then to 20wt.k., the bending strength and compressive strength of the synthesized PcBN show a tendency of first decreasing and then increasing.The AlN and AlB2 produced in the sintering process have bond effect on the whole PcBN and are also the places where the fracture is easy to occur.However, when TiC is used as binder, because of the strong inertness of TiC, there is no reaction between tic and cBN with high melting point, and the synthesized PcBN is still composed of cBN and TiC.Adding 10 wt.% TiC can make the synthesized PcBN have the densest structure and the sintered PcBN has better mechanical properties.When PcBN is sintered with Ti3AlC2 or Ti3SiC2 as binder at high temperature and high pressure, Ti3AlC2 or Ti3SiC2 will decompose and react with cBN during sintering, and finally, TiC0. 7N0. 3TIB 2 sic and AlN will be formed.For the cBN-Ti3AlC2 sintering group, the sintered PcBN has the densest structure and the highest bending strength, compressive strength and hardness when 20 wt.%Ti3AlC2 is added.When Ti3SiC2 is used as binder, PcBN sintered has the highest bending strength when 10wt.%Ti3SiC2 is added, 20wt.%Ti3SiC2 has the highest compressive strength, and PcBN with 40 wt.%Ti3SiC2 has the highest hardness and the densest structure.For the PcBNs synthesized by these four binders, one sample was taken for thermal analysis and the surface composition after oxidation was analyzed.After oxidation, oxide layers such as Al and Ti are formed on the surface of PcBN, and the cracks appear.Although the oxide layer is not compact enough, it can protect the PcBN material.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

【参考文献】

相关期刊论文 前9条

1 刘陟娜;许虹;王秋舒;陈梅;;全球金刚石资源分布现状及我国勘查开发建议[J];中国矿业;2016年07期

2 林峰;;超硬材料的研究进展[J];新型工业化;2016年03期

3 王光祖;卫凤午;;说说金刚石在功能应用方面的那些事[J];超硬材料工程;2013年06期

4 谢辉;冯飞;方海江;张迎九;;不同组分CBN-TiC-Al材料对PCBN性能的影响[J];金刚石与磨料磨具工程;2013年01期

5 刘建设;王飞山;;两面顶和六面顶压机在高温高压合成中的特点及对比分析[J];金刚石与磨料磨具工程;2012年05期

6 ;Layered Machinable and Electrically Conductive Ti_2AlC and Ti_3AlC_2 Ceramics:a Review[J];Journal of Materials Science & Technology;2010年05期

7 姜伟;吕智;王进保;李吉刚;冯吉福;李立惟;;低含量PcBN复合片在高温高压下的合成[J];超硬材料工程;2009年04期

8 王光祖;;我国第一颗人造金刚石的诞生[J];超硬材料工程;2008年04期

9 王光祖;;立方氮化硼(cBN)特性综述[J];超硬材料工程;2005年05期

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本文编号：1733987