掺钙的铬酸镧粉末制备工艺及烧结性能研究

采用固相法在不同工艺条件下烧结合成了掺钙的铬酸镧(La1-xCaxCrO3)粉末。对粉末进行了X射线衍射分析，用扫描电镜对烧结后试样的微观形貌进行观察，分析了钙含量及合成条件对试样晶体结构及烧结性能的影响。研究发现，微量钙的加入对晶体结构影响较小，但明显促进烧结致密化；随着粉体合成温度升高，烧结试样断面收缩率略有增大。合成温度决定粉体相结构，合成反应在1h内基本完成，延长合成时间对品体结构的影响不大。     

CuSn20粉末烧结体的微观分析及力学性能研究

为了研究CuSn20粉末经不同温度热压烧结后,其烧结体的微观相组成及其宏观力学性能与微观组织之间的关系,将两种不同的CuSn20粉末分别在三种烧结温度下热压烧结.借助扫描电镜、X射线衍射仪、显微硬度计等分析手段对烧结样品进行微观分析,运用硬度计和万能材料实验机测得样品的硬度和抗弯强度.结果显示:两种粉末的烧结体都主要包含富铜相α固溶体和α+δ共析体两种相,其中δ共析体是一种硬脆相,其质量分数随温度的升高先增大后减小.两种烧结体的硬度也随温度的升高先增大后减小,而抗弯强度随温度的升高是不断减小的.     

新型纳米磷酸铝致密陶瓷薄膜的制备与表征

在有机调整剂CTAB的作用下，将磷酸二氢铝溶液用氨水调节pH值在一定温度下合成纳米磷酸铝粉体，然后经高温烧结制得致密陶瓷薄膜。利用场发射扫描电镜（FESEM）表征了纳米磷酸铝的形貌特征和烧结后的陶瓷薄膜结构，热重（TG／DTA）分析了磷酸铝粉体烧结过程的失重和相转变吸放热过程，X射线衍射（XRD）分析跟踪了不同温度段烧结体系的组成变化趋势。结果表明，温度和pH值对磷酸铝纳米粉体的颗粒形貌和尺寸有较大的影响，纳米磷酸铝粉体在800℃左右即开始发生烧结，与普通磷酸铝陶瓷相比，烧结难度大大降低，同时烧结软化温度段相对较宽，利于针对不同应用体系进行烧结选择。FESEM表明，经1200℃烧结后形成的陶瓷薄膜与普通磷酸铝陶瓷膜相比具有很好的致密性，有利于发挥其在高温防护方面的作用。     

(Ti_2SnC+TiB_2)颗粒增强铜基复合材料的研究

在一定的Ti2SnC体积分数下,研究了添加不同体积分数TiB2对铜基复合材料组织和性能的影响。用X射线衍射(XRD)对不同烧结温度下的试样进行检测,分析其物相成分,确定了最佳烧结温度为850℃,观察不同配比试样的金相组织,对试样进行硬度、强度及电导率的测定。结果表明,当Ti2SnC含量为5%时,添加4%TiB2时,得到的铜基复合材料具有最佳的综合性能。     

MgB2烧结相变的研究

对自蔓延高温合成法制备的MgB2进行氩气保护下的烧结实验。通过X射线衍射、扫描电镜和EDX成分分析等方法，发现MgB2在流动氩气保护下于1050℃烧结后部分转化为MgB4。随着烧结温度提高，MgB4生成量增多。生成的MgB4晶粒形貌与MgB2的明显不同。     

烧结温度对La0.9Sr0.1 MnO3/Fe2O3体系结构和磁性的影响

采用软化学方法制备了纳米材料La0.9Sr0.1MnO3和软磁材料γ-Fe2O3,并将两者按不同比例进行复合,而后在不同温度下对其进行烧结,分别用扫描电子显微镜和X射线技术观察了样品的形貌特征和相结构,并用振动样品磁强计对烧结后的样品磁性进行测量.结果表明,经高温烧结后的复合体系,组成物质间没有发生反应,仍以各自相独立存在;复合体系剩磁Br及饱和磁化强度随烧结温度的升高而增加.烧结温度对样品晶粒和尺寸的影响是导致矫顽力Hc的变化的直接原因.     

烧结温度对ZrB2-SiC超高温陶瓷致密化的影响

利用放电等离子烧结技术（SPS）在不同的烧结温度下对ZrB2-SiC超高温陶瓷进行烧结，研究了烧结温度对烧结体致密化的影响。结果表明，在烧结温度分别为1650℃、1750℃、1850℃和1950℃，升温速度为200℃／min，保温时间为1min，压力为50MPa时，随着烧结温度的提高，烧结体的致密度呈上升趋势。当烧结温度高于1850℃时，烧结体的致密化过程明显加剧；通过对不同烧结温度下制得的试样的XRD谱图分析发现，当温度高于1850℃时ZrB2-SiC陶瓷中的SiC相会发生3C相到4H相的转变，这可能就是当烧结温度高于1850℃时烧结体致密度会急剧上升的原因。     

钌粉在不同温度下双向真空热压后的显微结构和晶体学演变（英文）

在温度为1050℃至1450℃、时间为2 h的条件下对钌粉进行了双向真空热压烧结。采用扫描电子显微镜(SEM)和X射线衍射(XRD)对烧结样品进行了分析。在1250℃烧结时,真空热压样品的相对密度达到理论密度的99.7%;当温度进一步升高,密度出现下降。在不同的烧结温度可以看到不同的晶粒和孔洞形貌。XRD数据表明在烧结过程中获得了(002)择优取向。随着烧结温度的增加残余应力有所减小。     

新型纳米磷酸铝致密陶瓷薄膜的制备与表征

在有机调整剂CTAB的作用下,将磷酸二氢铝溶液用氨水调节pH值在一定温度下合成纳米磷酸铝粉体,然后经高温烧结制得致密陶瓷薄膜.利用场发射扫描电镜(FESEM)表征了纳米磷酸铝的形貌特征和烧结后的陶瓷薄膜结构,热重(TG/DTA)分析了磷酸铝粉体烧结过程的失重和相转变吸放热过程,X射线衍射(XRD)分析跟踪了不同温度段烧结体系的组成变化趋势.结果表明,温度和pH值对磷酸铝纳米粉体的颗粒形貌和尺寸有较大的影响,纳米磷酸铝粉体在800℃左右即开始发生烧结,与普通磷酸铝陶瓷相比,烧结难度大大降低,同时烧结软化温度段相对较宽,利于针对不同应用体系进行烧结选择.FESEM表明,经1200℃烧结后形成的陶瓷薄膜与普通磷酸铝陶瓷膜相比具有很好的致密性,有利于发挥其在高温防护方面的作用.     

钌粉在不同温度下双向真空热压后的显微结构和晶体学演变

在温度为1050°C至1450°C、时间为2 h的条件下对钌粉进行了双向真空热压烧结。采用扫描电子显微镜(SEM)和X射线衍射(XRD)对烧结样品进行了分析。在1250°C烧结时,真空热压样品的相对密度达到理论密度的99.7%;当温度进一步升高,密度出现下降。在不同的烧结温度可以看到不同的晶粒和孔洞形貌。XRD数据表明在烧结过程中获得了(002)择优取向。随着烧结温度的增加残余应力有所减小。     

合金元素P,Cu含量对铸铁短纤维结合剂组织和性能的影响

本文研究了合金元素磷和铜对铸铁短纤维烧结体显微组织和性能的影响。结果表明，合金元素磷可显著提高铸铁短纤维烧结体的密度、致密化系数和压强度。磷与铜的共同加入可进一步提高烧结体的压溃强度和硬度，同时，铜的加入可抑制由磷引起的烧结体的急剧。烧结机理随磷、铜含量的增加逐渐由固相烧结＋瞬态液烧结转变为液相烧结。     

TiN对Ti(C,N)基金属陶瓷组织和性能的影响

研究了含Ni量很高的Ti（C，N）基金属陶瓷中TiN在烧结时的变化，及不同的TiN添加量对最终烧结体的N含量、组织和性能的影响。为Ti（C，N）基金属陶瓷的成分设计、烧结工艺的制定提供了一定的依据。     

Porous FeAl intermetallics fabricated by elemental powder reactive synthesis

Fabrication of porous FeAl intermetallics has been realized through the Fe and Al elemental powder reactive synthesis. The swelling behavior, synthesis process and microstructure of the porous FeAl intermetallics fabricated by reactive synthesis have been systematically studied. The pore structural parameters as a function of the sintering temperature have also been systematically investigated. It has been confirmed that the pore evolution in the porous FeAl intermetallics is attributed to the following four steps: the inter-particle pores formed during the pressing procedure, the Kirkendall pores formed during the solid-state sintering, pore formed through the liquid Al reaction, and the phase transformation during the high temperature sintering.     

CaCu3Ti4O12 ceramics from basic co-precipitation (BCP) method: Fabrication and properties

High dielectric CaCu₃Ti₄O₁₂ (CCTO) ceramics have been successfully prepared by a novel basic co-precipitation (BCP) method. Compared with the conventional solid-state and/or soft chemistry methods, the BCP method has many advantages such as relatively lower sintering temperature, shorter sintering time and lower costs. The XRD patterns confirm the formation of CCTO crystal phase in the as-prepared samples. Influences of initial ingredients and sintering condition on phase composition, microstructure and dielectric property have been investigated through series of trials. The correlation between the process of the grain growth and dielectric properties of final products has been explored. The final products exhibit the dielectric constants higher than 10,000 and the dielectric losses lower than 0.15 at 1 KHz.     

铁粉和铜粉的电火花放电烧结

对羰基铁粉、铜粉、铁铜混合粉以及B01粉（Fe、Co、Cu、Ni合金）进行了电火花烧结实验，研究了轻压放电阶段的烧结行为。讨论了保温时间对烧结体孔隙度、硬度（HRB）的影响。借助于液相在电火花烧结和热压烧结中的不同形态，分析了粉末体的两种烧结机制，结果表明电火花烧结工艺易在短时间内获得均匀的烧结体。     

Vacuum sintering of WC-8 wt.% Co hardmetals from WC powders with different dispersity

The effect of sintering temperature and particle size of tungsten carbide WC on phase composition, density and microstructure of hardmetals WC-8 wt.% Co has been studied using X-ray diffraction, scanning electron microscopy and density measurements. The sintering temperature has been varied in the range from 800 to 1600 °C. The coarse-grained WC powder with an average particle size of 6 μm, submicrocrystalline WC powder with an average particle size of 150 nm and two nanocrystalline WC powders with average sizes of particles 60 and 20 nm produced by a plasma-chemical synthesis and high-energy ball milling, respectively, have been used for synthesis of hardmetals. It is established that ternary Co₆W₆C carbide phase is the first to form as a result of sintering of the starting powder mixture. At sintering temperature of 1100-1300 °C, this phase reacts with carbon to form Co₃W₃C phase. A cubic solid solution of tungsten carbide in cobalt, β-Co(WC), is formed along with ternary carbide phases at sintering temperature above 1000 °C. Dependences of density and microhardness of sintering hardmetals on sintering temperature are found. The use of nanocrystalline WC powders is shown to reduce the optimal sintering temperature of the WC-Co hardmetals by about 100 °C.     

Critical current enhancement in Bi-2223/Ag superconducting tapes by controlling its first sintering process

Microstructural evolution of the Bi-2223 phase, liquid phase and secondary phase in the first sintering process has been studied by means of XRD and SEM/EDS. Experiments show that the first sintering temperature and time have a great influence on the Bi-2223 phase formation. The cooling rate after the first sintering process determines the type and grain size of the secondary phases, which in turn decides the critical current of the fully reacted tapes. The fast cooled sample contains a few secondary phase particles with very small size, whereas the slow cooled sample produces large CuO particles. The (Ca,Sr)₂CuO₃ and (Ca,Sr)₁₄Cu₂₄O₄₁ phases are easy to deform, while CuO phase particle has a high hardness and is difficult to deform during uniaxial press. The critical current is largely improved by controlling the cooling rate of the first sintering process.     

Fabrication of W–Ni–Fe alloys with gradient structures

A sintering couple of green compacts with compositions of 88W–5Mo–4.9–2.1Fe and 93W–4.9Ni–2.1Fe respectively, were processed by liquid phase sintering. The microstructure and content of binding phase at different regions along the direction perpendicular to the original interface were investigated by scanning electron microscopy (SEM). The distribution of Mo content in composite was determined by energy dispersive analysis (EDS) and the micro hardness in different regions were measured by Vickers micro hardness tester. Results show that the grain size, volume fraction of binding phase and micro hardness vary gradually due to the graded distribution of molybdenum, which also introduces a solid/liquid interfacial tension gradient and the unbalanced liquid phase pressure serving as the driving force for liquid phase migration during liquid phase sintering.     

Influences of Contents and Reaction of Carbon and Oxygen on Microstructure and Mechanical Properties of Sintered 93W-4.6Ni-1.9Fe-0.5Co Alloys

采用具有不同碳氧含量的初始粉末,利用真空液相烧结制备93W-4.6Ni-1.9Fe-0.5Co合金试样,研究碳氧含量的变化及其平衡反应对合金力学性能与组织的影响。结果表明,压坯在真空高温烧结过程中,原料自身含有的碳具有较强的脱氧能力,通过碳氧反应可减少合金中的氧、碳含量,阻止氧化物、碳化物夹杂的生成,在钨颗粒与粘接相之间形成牢固的界面。当合金总氧含量低于500μg/g时,合金的力学性能显著提高。     

Fabrication of single crystalline diamond reinforced aluminum matrix composite by powder metallurgy route

We have successfully fabricated highly densified aluminum (Al)-diamond composite materials by a simple hot press method. The thermal conductivity of the Al-diamond composite materials was measured. These materials had different types, sizes and fractions of diamond. These obtained values were discussed based on theoretically calculated values. The thermal conductivity of the composite materials, measured by Laser-Flash method, was found to have slightly increased compared to that of pure bulk Al. The obtained microstructures of the composite materials showed a lot of cleavage existing in the interface between the Al matrix and the diamond particles, which led to the low increment of the thermal conductivity. Moreover, Al-diamond bulk materials with different sintering temperatures in solid state, liquid phase, and transient region between solid and liquid of Al, have been synthesized.