添加BaCu(B2O5)和ZnO的CaO-Li2O-Sm2O3-TiO2陶瓷低温烧结研究

采用固相反应法制备了添加复合助烧剂BaCu(B<,2>O<,5>)-ZnO的16CaO-9Li<,2>O-12Sm<,2>O<,3>-63TiO<,2>(CLST)陶瓷研究了所制CLST陶瓷的烧结特性、微观结构及介电性能.结果表明:低熔点的BaCu(B<,2>O<,5>)-ZnO复合助烧剂的加入,使CLST陶瓷的烧结温...     

复合烧结助剂对 ZnNb2O6陶瓷的低温烧结与性能的影响

采用传统固相反应法制备了 ZnNb2O6陶瓷,研究了复合添加 BaO-CuO-V2O5(BCV)烧结助剂对 ZnNb2O6陶瓷的烧结特性、物相组成、微观组织形貌及微波介电性能的影响。结果表明：掺杂少量 BCV 的 ZnNb2O6陶瓷物相组成并未改变,仍为 ZnNb2O6单相。添加质量分数 2%的 BCV 可使 ZnNb2O6陶瓷的烧结温度降至 950 ℃,并且在 950 ℃烧结 3 h 具有较佳的微波介电性能：εr=24.7,Q·f=75 248 GHz,τf= –50.4×10–6/℃。     

低温常压烧成工艺制备Al2O3-SiC复相材料

将6H-SiC和α-Al2O3以质量比7:3混合,添加质量分数0~10%的MgO-CaO作为烧结助剂,球磨后的粉体压制成生坯,在1 200℃预氧化1 h后在氢气氛下常压烧结1 h制备Al2O3-SiC复相材料。研究了烧成温度和MgO-CaO含量对该复相材料烧结性能和相组成的影响。结果表明:1 500℃下,随着烧结助剂含量的增加,烧结致密性明显提高,当烧结助剂质量分数为10%时,显气孔率降至0.1%。预氧化时,添加烧结助剂MgO-CaO,方石英和α-Al2O3与之反应,生成CaAl2Si2O8和Mg2Al4Si5O18,促进6H-SiC的进一步氧化。烧成过程中,CaAl2Si2O8和MgAl2O4溶解生成玻璃相促进烧结,同时α-Al2O3从玻璃相中析出,1 500℃烧结试样所含物相为6H-SiC和α-Al2O3。     

纳米Al2O3激光烧结快速成型试验初探

将快速成型技术引入纳米材料成型领域,在Al2O3纳米粉末的选择性激光烧结试验基础上,系统分析了纳米陶瓷材料激光烧结工艺的影响因素,初选了烧结参数,得到了较为合理的纳米Al2O3粉末激光烧结工艺。通过多层烧结试验对其进行了验证,对烧结制件进行了成分、微观组织等检测分析。试验表明,采用得到的选择性激光烧结工艺,可以实现纳米Al2O3的自由成型,烧结制件内部组织保持纳米结构,材料晶粒尺寸基本不长大。     

无铅银浆烧结工艺与导电性能研究

制备了无铅低温玻璃粉,将其与银粉和有机载体混合配制成无铅导电银浆并烧结。通过SEM和EDX观察浆料烧结银膜的形貌并进行成分分析,用四探针测试仪测量烧结银膜的电阻率,讨论了浆料成分配比、烧结时间、烧结温度等方面对银膜导电性能的影响。确定了无铅导电银浆的最佳配比为:质量分数w(银粉)72%,w(玻璃粉)3%和w(有机载体)25%,最佳烧结温度为580℃,最佳保温时间为5min。     

Reactive sintering of Bi2Sr2CaCu2Ox superconductors

Three phase assemblages were used to produce Bi₂Sr₂CaCu₂O_x (2212) during sintering: a mixture of 20% Ca-rich 2212+80%2212, partially synthesized 2212, and Bi₂Sr₂CuO_x (2201)+(1/2 Ca₂ CuO₃+1/2 CuO) (denoted 0011). The mixture of 2201+0011 produced highly pure 2212 within 50 h of heating in air at ≈850°C. Ag tubes were filled with a mixture of 2201+0011 and worked into tapes by a powder-in-tube process. Heat treatments produced microstructures consisting of small, highly textured 2212 grains. T_c values were ≈70K. Transport J_c values at 4.2K were ≈10⁴ A/cm².     

助烧剂Bi_2O_3对叠层片式电感器性能及外观的影响

采用EDX、SEM等分析方法并结合实际生产,研究了助烧剂Bi2O3添加量对低温共烧叠层片式铁氧体电感器(MLCI)性能和外观的影响。结果表明:w(Bi2O3)为3%时,MLCI的质量最好。w(Bi2O3)为1%时,MLCI的烧结收缩率偏大,电感量和品质因数偏低;w(Bi2O3)为5%时,MLCI的品质因数偏低,直流电阻偏高,内电极银严重扩散,且表面出现金属斑点。     

The influence of minor titanium addition on thermal properties of diamond/copper composites via in situ reactive sintering

A minor amount of titanium addition is proposed to improve interfacial bonding between diamond particles and copper matrix for diamond/copper composites. The volume fractions of diamond and minor titanium in the sintering process are optimized. The microstructures, thermal properties, interface reaction production, and the effects of minor amount of titanium on the properties of the composites are investigated. The results show that the interfacial bonding of the composites could be strengthened by changing the volume fraction of titanium and diamond. The 45 vol%-diamond/copper composites with 3 vol% titanium at 945 °C for 5 min exhibits thermal conductivity as high as 670 W/(m K), which is 90% of the theoretical prediction value. High thermal conductivity is achieved by forming the titanium carbide (TiC) and intermetallic compounds (Cu₃Ti₂) at the diamond/copper interface to obtain a good interface.     

Effect of bismuth addition on sintering behavior and microwave dielectric properties of zinc titanate ceramics

The influences of Bi₂O₃ addition on the sintering behavior and microwave dielectric properties of ZnO-TiO₂ ceramics were investigated. ZnO-TiO₂ ceramics were prepared with conventional solid-state method and sintered at temperatures from 950°C to 1,100°C. The sintering temperature of ZnO-TiO₂ ceramics with Bi₂O₃ addition could be effectively reduced to 1,000°C due to the liquidphase effects resulting from the additives. A proper amount of Bi₂O₃ addition could effectively improve the densification and dielectric properties of ZnO-TiO₂ ceramics. The temperature coefficient of resonant frequency could be controlled by varying the sintering temperature and lead to a zero τ_f value. At 1,000°C, 1ZnO-1TiO₂ ceramics with 1 wt.% addition gave better microwave dielectric properties ɛ_r of 29.3, a Q × f value of 22,000 GHz at 8.36 GHz, and a τ_f value of +17.4 ppm/ °C.     

0.92MgAl_2O_4-0.08(Ca_(0.8)Sr_(0.2))TiO_3介质陶瓷微波烧结的研究

采用微波烧结法和常规烧结法制备0.92MgAl2O4-0.08(Ca0.8Sr0.2)TiO3微波介质陶瓷,研究了两种烧结方式对陶瓷烧结性能、微观结构、相组成和介电性能的影响。结果表明:与传统烧结方式相比,微波烧结0.92Mg Al2O4-0.08(Ca0.8Sr0.2)TiO3陶瓷缩短了烧结周期,其物相组成无变化,微波烧结后的样品致密度高,晶粒细小,分布均匀,介电性能更加优异。在1 440℃下采用微波烧结20 min制备的0.92MgAl2O4-0.08(Ca0.8Sr0.2)TiO3陶瓷获得最佳的介电性能,εr=11.20,Q×f=56 217 GHz,τf=–3.4×10–6/℃。     

Bi2O3掺入对CLST微波介质陶瓷性能的影响

研究了Bi2O3掺入对CaO-Li2O-Sm2O3-TiO2(简写为CLST)系微波介质陶瓷介电性能的影响。用XRD和SEM研究其晶体结构及微观形貌。结果表明:Bi2O3掺入能显著降低CLST陶瓷的烧结温度,由1300℃降至1200℃,1200℃烧结2h后,仍形成了斜方钙钛矿结构,但原有金红石相消失。掺入5%(质量分数)Bi2O3的CLST陶瓷取得了较好的介电性能:εr为93,tanδ为0.0078,τf为–29×10–6℃–1。     

激光烧结Al2O3/Ti系FGM的温度场与热应力场

用有限元法对激光烧结Al2O3/Ti系FGM的温度场和残余热应力场进行了模拟计算,并对烧结过程试样中的温度分布进行了实时测量.结果表明:激光照射面(Al2O3层)和背光面(Ti层)的温度落差为325℃.陶瓷侧温度梯度大于金属侧,成分梯度指数p值愈大,陶瓷侧温度梯度愈大.试样内残余热应力分布受p值控制,依据残余热应力最小且陶瓷层为压应力的设计准则,确定了激光烧结Al2O3/Ti系FGM的最佳成分梯度指数p=0.5.     

微波烧结法制备ITO陶瓷

采用微波烧结,在常压、纯氧气氛条件下制备了ITO陶瓷.通过XRD、SEM和金相分析等方法研究了烧结温度和保温时间对ITO陶瓷相对密度的影响.结果表明,微波烧结具有升温速度快、保温时间短的优点,大幅缩短了ITO陶瓷的烧结周期.1550℃微波烧结并保温20 min的ITO陶瓷相对密度达到了99.5%,晶粒大小均匀,结构紧密...     

添加Bi2ZnB2O7的CLST陶瓷的低温烧结

采用固相法在700℃合成单一相Bi2 ZnB2 O7 (BZB).添加BZB使16CaO-9Li2 O-12Sm2 O3-63TiO2(CLST)陶瓷的烧结温度降至1 050℃.随着烧结温度的升高,样品的体积密度先升高后趋于稳定.介电常数(εr)随着BZB添加量的增大先增大后略有减小,介电损耗(tan δ)则一直降低....     

CaO-SiO2-B2O3基板材料制备的研究

研究高温熔融法制备的CaO-B2O3-SiO2与溶胶凝胶法(sol-gel)法制备的CaO-B2O3-SiO2按不同比例制备的复相陶瓷,在850℃烧结温度下的晶相组成、微观结构、烧结性能、介电性能与导电浆料的匹配性.结果表明高温熔融法制备的CaO-B2O3-SiO2晶相含有大量的CaSiO3与少量的CaB2O4.添加sol-gel法制备的CaO-B2O3-SiO2后晶相无明显变化,但经SEM分析CaSiO3晶相长大,改善了体系的烧结性能与介电性能.当添加量为15.5%,在1 MHz下,可获得εr=5.80,tgδ=0.46× 10-4.     

Y_2O_3-MgO-Al_2O_3烧结助剂对SiC陶瓷烧结和导热性能的影响

对SiC粉体进行热处理,采用Y2O3-MgO-Al2O3烧结助剂,在1 750~1 950℃下30 MPa热压烧结1 h,制备SiC陶瓷。TG分析SiC的氧化特性,测定Zeta-电位研究SiC粉体的分散特性,测定其高温浸润性研究烧结助剂与SiC之间的亲和性。结果表明:SiC粉体热处理和提高SiC浆体的pH值,有利于提高Zeta-电位,进而提高分散均匀性;Y2O3-MgO-Al2O3烧结助剂高温下与SiC具有良好的浸润性;SiC粉体热处理明显降低了烧结温度。尽管Y2O3-MgO-Al2O3烧结助剂在高温下有一定的挥发,但是当其含量大于等于9%(质量分数)时,1 800~1 950℃下热压烧结可获得显气孔率小于等于0.19%的致密SiC陶瓷,其热导率大于190 W.m–1.K–1。     

低温烧结ZnO压敏陶瓷研究进展

ZnO压敏陶瓷具有优异的非线性特性,广泛应用于电子仪器和电力装置领域.为了满足电子元器件低压化、小型化和集成化的要求,必须开发出烧结温度低且能与Cu、Zn、Al等贱金属实现共烧兼容的ZnO压敏陶瓷体系.总结了当前ZnO压敏陶瓷低温烧结的研究现状,讨论了ZnO压敏陶瓷低温烧结方法的优缺点,同时分析了ZnO压敏陶瓷低温烧结...     

Laser sintering of thick-film PTC thermistor paste deposited by micro-pen direct-write technology

In this paper, laser sintering has been used to process thermal sensitive material deposited by micro-pen direct-write technology. Lines of thick-film PTC thermistor paste were deposited by micro-pen direct-write technology and irradiated by a continuous-wave laser with varied power density and scanning speed. Line widths, sheet resistivities and temperature coefficients of resistivity were measured as a function of laser power density, scanning speed, coating thickness and overlapped value. The mechanism of laser sintering thermistor paste was discussed. Laser sintering enabled finer thermistor lines to overcome the resolution limitation of micro-pen deposition without the use of any high temperature post processing. The thermistors exhibited excellent electrical performance and resistance tolerance equivalent to traditional oven-fired electronic paste.     

B2O3-Li2O低温助烧ZMSZT陶瓷的微波介电性能

为了研究了B2O3与Li2O添加剂对(Zn0.8Mg0.2)2SiO4-ZrO2-TiO2(ZMSZT)基微波介质陶瓷的性能影响,分别采用排水法、XRD、SEM以及网络分析仪表征单独添加及复合添加B2O3与Li2O的ZMSZT微波介质陶瓷的致密性、微观结构及介电性能。结果显示在ZMSZT陶瓷中同时添加1wt%B2O3和4wt%Li2O可有效提高其烧结性能,在930℃/3 h烧结条件下可以获得较高的致密性及微波介电性:ρ=3.83 g/cm3,εr=9.36,Qf≈30 120 GHz(f=10.3 GHz),τf=-5.71×10-6/℃。这种B2O3与Li2O复合添加的ZMSZT陶瓷可以应用到LTCC(低温共烧陶瓷)领域。     

Modification of cellulose acetate nanofibers with PVP/Ag addition

In this work cellulose acetate (CA) nanostructures were synthesized using electrospinning process. Silver nanoparticles (Ag NPs) were synthesized using silver nitrate as the starting precursor, ethanol as solvent and polyvinyl pyrolydone (PVP) as capping agent. The Ag NPs were added to the cellulose acetate (CA) nanostructures before and after CA electrospinning. The obtained CA and Ag-CA composite were characterized by various techniques such as, Fourier Transform Infrared (FTIR) spectroscopy, Raman Spectroscopy, Scanning electron microscopy (SEM) and Differential Scanning Calorimetry (DSC). It was found that Ag NPs can be effectively coated on or embedded into the electrospun CA and the PVP can lead to noticeable change in morphology and structure.