With the development of terahertz frequency band, the size of the slow wave structure, which plays key roles in realizing effective interaction between electron beams and terahertz signals, has decreased by an order of magnitude from mm to hundreds of μm scale. How to produce the high aspect ratio and fine-structure in such a small μm-scale structure has become a key factor that largely restricts the performance of terahertz devices. With the help of fully utilizing the excellent tolerance of UV-LIGA technology (Ultraviolet Lithography, Galvano forming, Abforming), the influence of intrinsic material properties of copper substrates (including oxygen content, grain size and distribution) on the surface polishing accuracy and slow wave microstructure processing accuracy are firstly investigated. The results indicate that low oxygen content and fine-grained substrates are beneficial for achieving high surface quality and precision of photolithography processing channels, which can satisfy the precision design requirements of 0.34 THz or even higher frequency terahertz slow wave structures.

Impurities and their distributions in osmium targets for M-type cathodes affect the coating quality on porous tungsten and cathode emission performance.Glow discharge mass spectrometry（GDMS） and X-ray photoelectron spectroscopy（XPS） were used to analyze the impurity contents and distributions in the osmium target.The chemical states of impurity elements were analyzed and characterized.The total amount of metallic impurity in the target was lower than 0.01 wt%.

High quality osmium targets are the key influence in improving the emission performance, lifetime and reliability of M-type cathodes. In this experiment, oxidative distillation was used to prepare osmium powder with a purity greater than 99.99%. The effect of hydrogen sintering and hot pressing sintering processes on the densities and grain size of the targets was investigated. The results show that the oxidation distillation process can effectively separate Os from Si, Fe, Ni, Zn and other impurity elements, and the purity of osmium powder prepared by multiple oxidation distillation was not less than 99.99%. Both hydrogen sintering and hot pressing sintering processes can be used to obtain osmium targets with a density of not less than 95%. However, the sintering temperature and time used in the hot pressing sintering process under pressure assistance are significantly lower than those of hydrogen sintering, which is more conducive to inhibiting grain growth during the high densification sintering process. By optimizing the parameters of the hot pressing sintering process, the sintering temperature of 1500°C and the holding time of 1.5h resulted in an osmium target with a density of 99.11% and a grain size of ≤12. XPS analysis of the highly dense fine crystalline osmium targets prepared by hot pressing sintering showed that the C and O mass fractions on the surface of the targets were 0.85% and 4.43% respectively, and the C and O contents gradually decreased with increasing etching depth. The above highly dense and fine crystalline osmium targets can be used in the M-type cathode standard coating process to obtain high purity, dense and strong bonded osmium films.

锇靶是制备M型阴极常用的一类靶材,须具有纯度高、致密度高、晶粒细小等特性,然而,传统工艺烧结因烧结温度较高获得的靶材晶粒较粗大,对阴极覆膜沉积不利.本研究对锇粉模压成圆饼压坯,之后采用微波烧结压坯.微波烧结锇压坯过程中以碳化硅、氧化锆作为辅助加热材料,氧化铝作为保温材料,升温速率在20～30 min/℃之间.结果 表明,当随着压强从100增加到300MPa,微波烧结1500℃保温60 min后,样品相对密度从80.61％快速增加到93.44％.当压强继续增加到400MPa时,相对密度随着压强的增长变缓达到94.25％.当压强从400增加到500MPa,烧结后样品的相对密度增长不明显,并有裂纹出现.锇烧结体的相对密度和直径收缩率随着保温时间的延长先快速增加,然后缓慢增加,最后增加趋于平缓.在微波烧结1500℃下,随着保温时间的延长直径收缩率从11.67％快速增加到14.99％,然后缓慢增加到15.56％,相对密度从87.97％快速增加到93.78％,然后缓慢增加到94.25％,而孔隙的数量和尺寸随着保温时间的延长而减小,最终呈球形,晶粒尺寸在1 μm左右.

Os sintered body was prepared by microwave sintering process. The influences of the green compact pressure and the microwave sintering parameters (heating rate, sintering temperature, and holding time) on the microstructure and relative density of Os sintered bodies were investigated. The densification mechanism of Os microwave sintering was analyzed. The results show that, the average grain size of Os after microwave sintering at 1350 ℃ is about 0.22 μm, which is close to the average particle size of the Os powders. With the increase of the sintering temperature to 1500 ℃, the grain size grows to 0.76 μm. The relative density of the Os sintered body increases rapidly at first and then slowly after prolonging the holding time sintered at 1500 ℃. After microwave sintering at 1500 ℃ for 60 min, the relative density of the Os sintered body is 94.3%, and the average particle size is less than 1 μm. The sintering kinetics analysis shows that the densification process of Os is the result of the combined action of volume diffusion and grain boundary diffusion. With the increase of the sintering temperature, the diffusion mechanism gradually transfers from grain boundary diffusion to volume diffusion.

Al0.7Sb2Te3 ternary target was prepared by vacuum synthesis and sintering-HIP using mixed powder of Al, Sb and Se in an atomic ratio of 0.7:2:3 as raw material. Target properties were characterized by XRD, FESEM, EDS and XPS, and the state of Al in the ternary target was researched primarily by XPS. The results show that with aluminum doping, the lattice constant of main phase Sb2Te3 changes, and the aluminum dispersoids can coexist together with Al0.1Sb2Te3 matrix, which confirms the effect of aluminum doping on target organization structure; with the increase of the etching depth from 0 to 405.9 nm, the aluminum's valence is gradually transferred from the compound state of Al2O3 to simple substance state, and the area depth of aluminum dominated by Al2O3 is about 90 nm; XPS analysis with the etching depth of 405.9 nm shows the aluminum of Al0.1Sb2Te3 matrix influences target structure by effective formation of AlSb.

Al-Sb-Te相变薄膜与CMOS兼容性高,热稳定性佳,所以能很好满足相变存储器高温稳定工作的需求.以原子比Al∶Sb∶Te=0.7∶2.0∶3.0的混合粉为原料,采用真空合成法与烧结-热等静压制备Al-Sb-Te合成粉及用于溅射沉积Al0.7 Sb2Te3薄膜的三元靶材,通过X射线衍射仪(XRD),场发射扫描电镜(FESEM)及金相显微镜(OM)、能谱仪(EDS)分别表征粉体物相、靶材显微组织及元素分布等.结果 表明:Al0.7Sb2Te3合成粉的主相为Sb2Te3相,且与Sb2Te3二元合金粉相比,Al原子的掺杂使Sb2Te3主相的品格常数与晶胞体积均减小,具体表现为:品格常数a,c从Sb2Te3二元合金粉的0.4267,3.0443 nm减小到Al0.7Sb2Te3合成粉的0.4258,3.0423 nm,且晶胞体积减小0.486％;再用Al0.7 Sb2Te3合成粉为原料,制备出的三元靶材相对密度达到99.5％,且其平面与截面显微组织基本一致,均形成明显的Al0.1Sb2Te3基体相与单质Al弥散相两相组成,基体相与弥散相结合紧密,界面处存在宽度2～3 μm的过渡区域.所制备的近全致密两相Al0.7Sb2Te3合金靶材,有望改进磁控溅射法制备Al-Sb-Te系列薄膜的工艺和效果.

以原子比Al:Sb:Te=0.7:2:3的混和粉为原料,采用真空合成法与烧结-热等静压制备Al 0.7 Sb 2 Te 3 三元靶材,通过XRD、FESEM、EDS、XPS等手段表征其性能,且重点采用XPS研究Al在Al 0.7 Sb 2 Te 3 三元靶材的存在状态。结果表明:Al掺杂后,靶材主相Sb 2 Te 3 的晶格常数变化,且单质Al弥散相与Al 0.1 Sb 2 Te 3 基体相共存,表明掺杂对靶材的组织结构确有影响;刻蚀深度从0 nm增加至405.9 nm,Al价态从以Al 2 O 3 的化合态为主逐渐过渡至以单质态为主,且Al以Al 2 O 3 形态为主的区域深度约90 nm;刻蚀深度为405.9 nm的XPS分析表明,Al 0.1 Sb 2 Te 3 中的Al通过有效化合形成AlSb影响着靶材的组织结构。

According to the failure mechanism of the cathode used in space travelling wave tubes,the developments of cathode material were illustrated and factors limiting the long-lifetime of cathodes were analyzed.Effects of particle characteristics and porous performance of the substrate on evaporation rate of active material penetrating into the substrate were discussed.The work function of M-cathode would change continuously in working process because of the influence of elemental alloying on surface,barium supplying in channels and surface coverage.It was suggested that narrow size distributed powders with regular shapes and mean grain size of 4 μtm were helpful for improving porous property and reducing percentage of close pores.Mixing cathode substrate with noble metal Os or Ir,or covering cathode surface with Os or Ir film,could effectively slow down the alloying speed,reduce the evaporation,keep low work function,and so improve cathodes lifetime.

采用直接氮化法对铝粉进行氮化,分别研究了添加剂、反应温度、保温时间对合成产物的影响。运用扫描电镜（SEM）、X射线衍射物相分析（XRD）、X射线荧光光谱分析（XRF）对合成产物进行了表征,研究结果表明:提高反应温度、延长保温时间可以有效促进铝粉转化为氮化铝,提高合成产物的氮含量。同时提高反应温度可以促进添加剂的挥发,减小杂质元素的残留量。在1000℃下保温3 h后,对多孔疏松的合成产物进行球磨24 h处理,最终可以得到氮含量大于32%,Cl的残余含量低于0.3%,K的残余含量低于0.1%,平均粒度小于2μm氮化铝粉末。同时在多孔疏松状合成产物表面观察到了氮化铝晶须的存在,这说明铝粉直接氮化法也可以制备出氮化铝晶须。

Os–Ir–Al alloy was fabricated by powder metallurgy technique. IrAl and OsIr interalloys were synthesized to reduce the Al evaporation and ensure the composition of the ternary alloy. Analysis on microstructures shows that each component is distributed homogeneously, and the green density reaches 94.9 %. Ba–W cathodes with Os–Ir–Al alloy magnetic sputtered on the tips are prepared and directly current density tests are carried out on these cathodes. It is found that at 1,050 °C, the average zero field emission density of the cathode reaches up to 20 A·cm−2. The improvements of cathodic current density and stability may indicate the prosperous application of Os–Ir–Al alloy on cathode.

Diamond composites with diamond volume fraction up lo 80 % is prepared by high temperature and high pressure( HTHP) sintering method. Factors including particle size, sintering temperature and sintering time are investigated to illustrate the influence on romposition. interfacial state and thermal conductivity of the composites. The results indicates that a high thermal conductivity value of 639 W · m -1 · K -1 could he achieved when diamond particle diameter is 80 μm .A critical diameter value is determined by the volume fraction of diamond,and the thermal conductivity of the composite increases with the particle diameter increasing and then lends to decrease when it reaches tin-critical value: An optimal match of sintering temperature and sintering time is beneficial for a good cohesion at the interface and good thermal conductivity of the composites.

Diamond-Cu composites were produced by special powder metallurgy technique.Diamond/Cu interface of the composites was investigated by SEM,EDS and Raman spectrum methods in this paper.The results indicate that thermal conductivity of the composites obtained at optimal parameter is about 570W·m-1·K-1.Proper addition of Co could improve interfacial bonding between diamond and Cu during sintering process.As a result of Co diffusion in diamond and solution in Cu melts,transition layers are formed at diamond/Cu interface,which can greatly promote the compatibility between diamond and Cu.Furthermore,diamond skeleton is considered important for ultrahigh thermal properties.

Mo-Cu alloys with the higher thermal conductivity and lower coefficient of thermal expansion is widely used as electrical packaging materials and heat sink materials. The effects of mass fraction of element Ni on the density, sintering properties, theromo-conductivity, electric-conductivity, and microstructures of Mo-Cu alloys were investigated. The results indicate that addition of element Ni decreases the sintering densification temperature of the alloy. However, it is not beneficial to the theromo-conductivity and electric-conductivity and microstructures. 75Mo-20Cu-5Ni alloy is a kind of good, matchable electronic sealing material for 95%Al 2O 3 ceramics.

Mo-Cu composites with the higher thermal and electronic conductivity and lower thermal expansion coefficient is a new type material being investigated widely. Solid phase sintering and liquid phase sintering of Mo-Cu composites were investigated and sintering mechanism of Mo-Cu composites was analyzed. The results showed that microstructure of Mo-Cu composites by solid phase sintering was worse, there were a large amount of holes in body, and densification was lower while liquid phase sintering of Mo-Cu composites might be divided into three stages including rearrangement, solution reprecipitation and solid phase sintering of Mo.

Diamond-copper composites were prepared by powder metallurgy, in which the diamond particles were pre-coated by magnetic sputtering with copper alloy containing a small amount of carbide forming elements (including B, Cr, Ti, and Si). The influence of the carbide forming element additives on the microstructure and thermal conductivity of diamond composites was investigated. It is found that the composites fabricated with Cu-0.5B coated diamond particles has a relatively higher density and its thermal conductivity approaches 300 W/(m·K). Addition of 0.5%B improves the interfacial bonding and decreases thermal boundary resistance between diamond and Cu, while addition of 1%Cr makes the interfacial layer break away from diamond surface. The actual interfacial thermal conductivity of the composites with Cu-0.5B alloy coated on diamond is much higher than that of the Cu-1Cr layer, which suggests that the intrinsic thermal conductivity of the interfacial layer is an important factor for improving the thermal conductivity of the diamond composites.

讨论了采用熔渗法制备高密度钨铜和钼铜合金,综合其密度、比热容、热膨胀系数、导热系数等基本数据,比较了合金的热物理性能及其应用上的特点。结果表明：与W-Cu合金相比,Mo-Cu合金从热力学角度考虑制备更困难,采用特殊工艺方可获得高致密性;Mo-Cu合金质轻且散热速率和稳定性优良,与常用基片材料Al2O3、芯片材料GaAs的热膨胀匹配性更好。

As the higher thermal conductivity, the lower coefficient of thermal expansion and higher heat-resistance, the Mo-Cu alloy is widely used in sealing material to ceramics, electrical contact material and heat sink material. Preparation technologies and their respective characteristics were illustrated. According to the requirements in application, approaches of densification were summarized and development trends in preparing highly-densified alloys were demonstrated.

Mo-Cu alloy of high thermal conductivity and low thermal expansion coefficient is widely used as electrical packaging material and heat sink material.The properties,fabricating methods,application and development of Mo-Cu alloy are described.The process of densification is summarized.The problems in production are discussed.

Mo-Cu-Ni alloys with a density up to 99.97% of the theoretical were made by P/M technology.Microstructures and properties including physical,mechanical as well as technological properties were investigated.The results indicated that after special technical process Mo-Cu-Ni alloy was found to be entirely densified.The alloy was consisted of Mo matrix phase and Cu_(3.8)Ni binder phase which distributed around the matrix.The expansion coefficient of Mo-Cu-Ni ceramic hermetic materials was demonstrated to be close to that of 95% alumina,and the electro-conductivity and thermal-conductivity were excellent either.In addition,a good match in moderate strength and preferable elongation was presented.Later work carried out on welding subassemblies proved that air tight seal and technological performance of the alloy had achieved the rigorous applied requirements.