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1.
沈强  张联盟 《硅酸盐学报》1997,25(4):406-412
选择Ni/Ni3Al-TiC体系的FGM,对其在制备过程的残余热应力进行了计算机用限元模拟,在综合考虑热应力最小,热应力发生位置以及纯TiC侧应力状态等因素的基础上,完成了FGM的组成结构设计与优化,得到了组成分布指数P=1.6的最佳设计结果,按此设计结果,采用热压烧结工艺,制行出完整的,无宏观缺陷的Ni/Ni3Al-TiC系FGM样品。  相似文献   

2.
Ni/Ni_3Al-TiC系梯度功能材料的组成结构设计与制备   总被引:2,自引:0,他引:2  
选择Ni/Ni3AlTiC体系的FGM,对其在制备过程中的残余热应力进行了计算机有限元模拟。在综合考虑热应力最小、热应力发生位置以及纯TiC侧应力状态等因素的基础上,完成了FGM的组成结构设计与优化,得到了组成分布指数P=1.6的最佳设计结果。按此设计结果,采用热压烧结工艺,制备出完整的、无宏观缺陷的Ni/Ni3AlTiC系FGM样品。  相似文献   

3.
Ni/Ni3Al—TiC系梯度功能材料的热应力缓和特性设计   总被引:1,自引:0,他引:1  
沈强  张联盟 《硅酸盐通报》1997,16(2):34-36,40
本文选择Ni/NiAl-TiC体系的FGM,对其在制备过程中的残余絷应力进行了计算机有限元模拟。在综合考虑热应力最小,应力强度比值最小以及纯TiC侧应力状态等因素的基础上,完成了FGM体系的热应力缓和特性设计,得到组成分布指数P=1.6的最佳设计结果。  相似文献   

4.
PSZ-Mo系梯度功能材料的热应力缓和设计与制备   总被引:3,自引:0,他引:3  
对PSZ-Mo系梯度功能材料(functionallygradientmaterials简称FGM)在制备过程中的热应力缓和性能进行了优化设计,用有限元方法解析了PSZ-Mo系两层叠层材料(即非梯度功能材料)在制备过程中的热应力分布情况。同时解析了PSZ-Mo系FGM在制备过程中的热应力分布及缓和规律。揭示了PSZ-Mo系FGM在制备过程中的热应力大小与组成分布形状指数P的关系,对所研究的体系通过热应力解析,得到制备中热应力缓和最佳时的P值,同时,对FGM的制备工艺进行了研究,用粉末法分别制备出24mm×5.6mm和30mm×5mm完整的FGM试样。  相似文献   

5.
PSZ—Mo系梯度功能材料的热应力缓和设计与制备   总被引:10,自引:0,他引:10  
对PSZ-Mo系梯度功能材料在制备过程中的热应力缓和性能进行了优化设计,用有限元方法解析了PSZ-Mo系两层叠层材料(即非梯度功能材料)在制备过程中的热应力分布情况。同时解析了PSZ-Mo系FGM在制备过程中的热应力分布及缓和规律。揭示了PSZ-Mo系FGM在制备过程中的热应力大小与组成分布形状指数P的关系,对所研究的体系通过热应力缓和最佳时的P值,同时,对FGM的制备工艺进行了研究,用粉末法分别  相似文献   

6.
张联盟  涂溶 《硅酸盐学报》1996,24(4):418-422
通过实验方法,测定了TiC/Ni3Al复合材料的诸物性参数,在此基础上,对于TiC/Ni3Al系梯度材料(FGM)在稳定状态下产生的隔热应力,利用有限元方法进行了热弹性模型下的三维解析,在考虑热应力最小,比应力最小以及TiC侧应力状态等因素之后,对圆反状TiC/Ni3Al系梯度材料的组成分布进行了优化。  相似文献   

7.
朱雪梅  贺玲 《化工时刊》1998,12(12):16-18
在强碱条件下,MnCl2和Mg(MnO4)2反应,选用Ni^2+作模板剂,通过水热合成法制备新型催化材料锰氧化物八面体分子筛Ni-OMS-1,用RXD、BET、FT-IR等分析手段对所得样品进行表征。  相似文献   

8.
镍铁合金镀液故障处理郭绍湘(山东红旗机械厂,261031)1简介双层镍铁合金/装饰铬生产线,Ni-Fe槽液成份及工艺规范如下:NiSO4·7H2O300~350g/L,H3BO340~45g/L,NaCl15~18g/L,Fe总1~2.5g/L,Na...  相似文献   

9.
染料中间体废水多相催化氧化中几种催化剂的筛选研究   总被引:12,自引:0,他引:12  
对于高浓度染料中间体废水多相催化氧化处理工艺的催化剂进行了研制工作,选择了染料中间体废水中的吐氏酸废水为处理对象。结果表明,过渡金属氧化物中Ni2O3与MnO2是具有较高催化活性的组分,Cu、Fe等金属的氧化物没有明显的催化活性,但与Ni,Mn等组分相混合,却能体现较高的催化活性,而且,添加少量的K2O具有明显的助催化作用。对COD为1500mg/L左右的叶氏酸废水,在O3投加量达1g/L时,CO  相似文献   

10.
Mo—Ni/Al2O3催化剂的TPR特性与加氢脱硫性能   总被引:7,自引:0,他引:7  
程伟  周俐 《化学工业与工程》1998,15(4):30-33,43
应用TRP、XPS及XRD等技术研究了用浸渍法制备了的Ni/Al2O3、Mo/Al2O3和Mo-Ni/Al2O33种催化剂的还原性能,并将Mo-Ni/Al2O3双金属催化剂与同类型的Mo-Co/Al2O3和W-Ni/Al2O3催化剂进行了比较。结果表明:在Mo-Ni-Al2O3中,MoO3呈高度分散状态,NiO的加入减弱了Mo与载体间的强相互作用,并在催化剂表面形成了两种易还原的复合物,大大降低了  相似文献   

11.
Ni/MgO solid solution catalyst was prepared by decomposition of nickel and magnesium nitrate using dielectric barrier discharge (DBD) plasma operated at atmospheric pressure and less than 175 °C. Well-defined lattice fringes of the Ni (111) plane are clearly observed in the plasma prepared Ni/MgO catalyst. The plasma prepared catalyst possesses fewer defects, compared to the catalyst prepared by thermal decomposition at elevated temperature. It results in a better balance between the carbon formation and the carbon nanotube (CNT) growth. The crystallinity of the Ni particle from thermal decomposition is more complex. It is difficult to distinguish the Ni planes with the thermal decomposed catalyst. CNTs from CO decomposition over the plasma made catalyst show a narrow diameter distribution with a high aspect ratio. The DBD plasma decomposition is a facile, simple and effective way for the preparation of Ni catalysts to fabricate high quality CNTs.  相似文献   

12.
赵军  艾兴  李艳征 《硅酸盐学报》2006,34(11):1362-1366
推导和提出了第三类边界条件下梯度功能材料(functionally gradient materials,FGM)圆球的瞬态温度场及瞬态热应力场表达式.基于陶瓷材料的临界应力断裂判据,通过求解梯度功能陶瓷圆球表面达到其局部断裂强度的时间,建立了引起其表面临界热应力的临界温差△Tc的表达式,并以此作为梯度功能陶瓷圆球的抗热震参数.通过计算实例并与均质陶瓷圆球对比,分析了材料的热-物理性能分布规律对其抗热震性的影响,并提出了高抗热震性FGM陶瓷圆球的设计原则:线膨胀系数和热扩散率应由表及里增大,而弹性模量应由表及里减小.  相似文献   

13.
MgO-supported Mo, CoMo and NiMo sulfide hydrotreating catalysts   总被引:2,自引:0,他引:2  
The most common preparation of high surface area MgO (100–500 m2 g−1) is calcination of Mg(OH)2 obtained either by precipitation or MgO hydration or sol–gel method. Preparation of MoO3/MgO catalyst is complicated by the high reactivity of MgO to H2O and MoO3. During conventional aqueous impregnation, MgO is transformed to Mg(OH)2, and well soluble MgMoO4 is easily formed. Alternative methods, that do not impair the starting MgO so strongly, are non-aqueous slurry impregnation and thermal spreading of MoO3. Mo species of MoO3/MgO catalyst are dissolved as MgMoO4 during deposition of Co(Ni) by conventional aqueous impregnation. This can be avoided by using non-aqueous impregnation. Co(Ni)Mo/MgO catalysts must be calcined only at low temperature because Co(Ni)O and MgO easily form a solid solution. Literature data on hydrodesulfurization (HDS) activity of MgO-supported catalysts are often contradictory and do not reproduced well. However, some results suggest that very highly active HDS sites can be obtained using this support. Co(Ni)Mo/MgO catalysts prepared by non-aqueous impregnation and calcined at low temperature exhibited strong synergism in HDS activity. Co(Ni)Mo/MgO catalysts are much less deactivated by coking than their Al2O3-supported counterparts. Hydrodenitrogenation (HDN) activity of Mo/MgO catalyst is similar to the activity of Mo/Al2O3. However, the promotion effect of Co(Ni) in HDN on Co(Ni)Mo/MgO is lower than that on Co(Ni)Mo/Al2O3.  相似文献   

14.
A facile synthesis of the hierarchical Ni/MgO catalyst is reported, with extremely fine dispersion of Ni nanoparticles (NPs) and high surface oxygen mobility. The hierarchical Ni/MgO catalyst exhibits higher activity for CH4 formation than that prepared by the impregnation method. The enhanced activity and thermal stability of the hierarchical Ni/MgO catalyst is attributed to hierarchical MgO particles with a multilayer structure and high surface oxygen mobility. This induces better metal‐support interactions, high Ni dispersion to prevent Ni NPs sintering, and the high surface oxygen mobility provides a high resistance to carbon deposition. Compared to the impregnated Ni/MgO catalyst, the hierarchical Ni/MgO catalyst exhibits a better fluidization quality and a higher attrition‐resistance in a fluidized‐bed reactor. This approach to improve the catalytic activity by creation of hierarchical Ni/MgO particles is encouraging for the design of novel catalysts for synthetic natural gas production, especially from the perspective of matching catalysts with fluidized‐bed reactors. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2141–2152, 2017  相似文献   

15.
负载型氨分解催化剂的载体——高岭土的研究   总被引:1,自引:0,他引:1  
为了拓展高岭土在化工领域的应用,研究了将其作为催化剂载体应用于氨分解的可行性。通过正交实验确定了高岭土载体制备过程中最大影响因素,进而确定最佳制备条件。将其制备成负载型Ni基催化剂,进行氨分解活性评价,结果表明,与工业MgO载体比较,自制高岭土载体可以达到工业MgO载体的同等水平,在氨分解反应中可替代工业MgO载体。  相似文献   

16.
采用有限元法研究ECBC边界下中间夹FGM金属/陶瓷复合板的稳态热应力问题,检验了研究方法的正确性,给出了该材料复合板的稳态热应力场分布(Ta=500K,Tb=1800K)。结果表明,FGM层厚度的增加对ECBC复合板的稳态热应力影响不明显。当M=1时,热应力曲线平缓而光滑;当M=0.1和10时,热应力曲线出现明显的转折点;随着FGM层孔隙率的增大,三层板的衔接界面处,热应力变化增大,曲线出现钝角;与金属/陶瓷二层复合板界面处热应力出现突变相比,夹FGM金属/陶瓷复合板的热应力非常缓和。此结果为该复合板的设计和应用提供了准确的理论计算依据。  相似文献   

17.
J.I. Kim  W.-J. Kim  D.J. Choi  W.-S. Ryu 《Carbon》2005,43(8):1749-1757
To reduce the residual thermal stress between the carbon fiber-reinforced carbon (C/C) composites and the SiC coating layer, functionally graded materials (FGM) consisting of a C/SiC compositionally graded layer (C/SiC interlayer) were adopted. After designing the compositional distribution of the C/SiC interlayer which can relieve the thermal stress effectively, the deposition conditions of the entire compositional range of the C/SiC composites were determined using a thermodynamic calculation. According to the design and calculation the C/SiC interlayer and the SiC outer layer were deposited on the C/C composites by a low pressure chemical vapor deposition (LPCVD) method at deposition temperatures of 1100 and 1300 °C. The stress calculation and the experimental results suggested that the SiC-rich compositional profile in the FGM layer is the most effective for relieving the thermal stress and increasing the oxidation resistance.  相似文献   

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