化学成分及退火温度对连续退火再结晶织构的影响

在MULTIPAS平台上模拟了不同化学成分的IF钢的两种连续退火生产方案。通过X衍射仪和全自动拉伸试验机对样品进行了检测,结合织构分布及力学性能分析了化学成分及退火温度等对IF钢再结晶织构的影响。研究发现当退火温度大于800℃时,退火温度对〈111〉//ND织构强度无显著影响,得到了C、N、Ti元素含量与样品织构的关系。     

退火温度对BZT薄膜微结构的影响研究

采用Sol-gel法在Pt/Ti/SiO2/Si衬底上制备了Ba(Zr0.2Ti0.8)O3(BZT)薄膜.X射线衍射分析表明,该BZT薄膜为钙钛矿结构而无其他物相存在.光学显微镜分析结果表明,退火温度为900℃时,BZT薄膜表面光滑平整,无裂纹产生.     

烧结温度对不锈钢（316L)致密性及强度的影响

以不锈钢粉为原料,经１００ＭＰａ冷成型于空气中以不同温度烧结,通过测定其相对密度,线收缩率和抗弯强度、研究温度对材料致密化和强度的影响,结果表明：烧结温度升谪,相对密度和抗弯强度增加,温度超过１２００℃时两者的增加趋于平缓。     

退火温度对MgB2超导薄膜的影响

本实验是研究退火温度对MgB2超导薄膜的影响。在多晶Al2O3衬底上,以B2H6作为硼源,化学气相沉积先驱硼薄膜,采用Mg扩散方法,在不同退火温度条件下制备了MgB2超导薄膜;还采用了测量电阻-温度曲线、X射线衍射分析和扫描电子显微镜形貌观测方法。结果表明,退火温度对MgB2薄膜的超导特性、晶体结构和相纯、表面形貌有影响。退火温度高,生成的MgB2晶粒较大,晶形好,正常态电阻也增大,杂相越少。     

退火温度对球墨铸铁的组织与力学性能的影响

利用某铸造企业单铸的圆柱形试棒进行不同温度下的退火实验,检测分析了退火温度对球墨铸铁的组织和力学性能的影响。结果表明:退火温度越高,渗碳体溶解越快,粒状渗碳体越多。在710～750℃范围内,随着退火温度的升高,试样的抗拉强度会降低,延伸率会升高。与铸态试样相比,在退火温度相对较低的710℃时,因微量碳原子固溶强化作用,碳原子在石墨上的沉积以及石墨化过程中体积膨胀,增强了石墨与基体的结合强度,退火态试样的抗拉强度增加了6%,而渗碳体的球化使得其延伸率也略有增加。在退火温度为710℃时,试样可获得相对最佳的力学性能。     

退火温度对ZnO薄膜结构及光学性能影响

以二水醋酸锌为原料,使用溶胶凝胶法在玻璃基体上旋涂氧化锌薄膜.用X射线衍射、室温光致发光、可见分光光度计等方法对薄膜的结构、光学特性进行了研究,同时结合AFM和分光光度计,讨论了不同退火温度对氧化锌薄膜结构,透光率的影响.结果表明随着退火温度的升高,ZnO薄膜衍射峰增强,其中在500 ℃时,(002)峰最强,即沿C轴的取向性最好,晶粒尺寸依次增大,其中500-550 ℃时,晶粒尺寸比较小且分布均匀,平均粒径40 nm,表面粗糙度最小,小于8 nm;退火温度为550 ℃时,ZnO薄膜的透光率最高,达96%以上.并在380 nm附近有很强的紫外发射峰.     

退火工艺对低碳齿轮钢球化退火组织影响

通过对低碳20CrMnTiH齿轮钢在不同保温温度及保温时间进行直接淬火和球化退火试验,分析了退火温度及时间对齿轮钢球化退火组织及硬度的影响。     

低温退火温度对硅晶圆内V-O2对介观演变影响的仿真

为了揭示低温退火温度对硅晶圆内V-O2对介观演变的影响,基于所建相场模型及其应用程序,对2个不同温度下退火的硅晶圆中V-O2对演变过程进行了仿真.结果表明:当低温退火温度降低时,V-O2对变化速率减慢、数量减少,这与相应的空位相对浓度演变及其均匀化过程有关.     

退火温度对碳化硅涂层微观结构与形貌的影响

采用射频磁控溅射技术,在锆合金基体上制备厚度约为1.8 μm的SiC涂层,对其在不同温度下进行退火处理。利用SEM和AFM对微观形貌进行分析,讨论不同温度对SiC涂层表面形貌的影响,利用XRD对涂层的结构进行研究。结果表明:随着退火温度从400 ℃升高到800 ℃,涂层表面粗糙度呈现先减小后增大的趋势,其中在600 ℃时表面粗糙度最小,为0.122 μm;退火温度低于600 ℃时,SiC涂层不会出现晶态转变,当温度高于700 ℃时涂层开始出现非晶态向晶态的转变,XRD衍射图谱中开始出现SiC对应的衍射峰,且随着退火温度的升高,涂层的晶化程度进一步增大。     

退火温度对MoS2 薄膜光学性能的影响

在大气条件下采用激光剥离技术制备了MoS₂ 薄膜, 研究了MoS₂ 薄膜在不同退火温度条件下的形貌结构及其光学性能。实验研究发现, 退火温度对MoS₂ 薄膜表面的作用显著, 并且退火温度的不同会使得MoS₂ 薄膜XRD 图谱中衍射峰的位置产生明显的偏移。随着退火温度的升高, 薄膜生长质量及其吸光度都得到明显的提升。进一步对比分析了不同退火温度下MoS₂ 薄膜光学性能的差异, 结果显示退火温度为850 ℃ 时MoS₂ 薄膜的光学性能最佳。     

Ag/SiO_2和Ag-Cu/SiO_2纳米催化剂的制备与表征

以SiO2为载体在离子液体环境下合成了Ag/SiO2和复合纳米粒子Ag-Cu/SiO2催化剂,讨论了还原剂水合肼的浓度、离子液体用量对纳米粒子生成的影响,通过SEM、XRD、N2吸附-解析对其进行了表征。结果表明,制备时加入离子液体后纳米颗粒较小,形状较为均一,当水合肼浓度为0.1mol/L时,易于生成纳米粒子尺寸较小的纳米银。将Ag/SiO2与Ag-Cu/SiO2纳米粒子催化性能进行了比较发现,在甲烷氧化的性能测试中,Ag/SiO2优于Ag-Cu/SiO2的催化性。     

Fabrication and characterization of SiO2（f）/Si3N4 composites

A silicon dioxide fiber-reinforced silicon nitride matrix (SiO2/Si3N4) composite used for radomes was prepared by chemi- cal vapor infiltration (CVI) process using the SiCl4-NH3-H2 system. The effects of the process conditions, including infiltration tem- perature, infiltration time, and gas flux were investigated. The energy dispersion spectra (EDS) result showed that the main elements of this composite contained Si, N, and O. The X-ray diffraction (XRD) results indicated that phases of the composite before and after treatment at 1350°C were all amorphous. A little fiber pull-out was observed on the cross section of the composite by scan electron microscope (SEM). As a result, the composite exhibited good thermal stability, but an appropriate interface was necessary between the fiber and the matrix.     

二氧化硅和高岭土杂质对硫铁矿分解磷石膏的影响

:针对磷石膏资源化利用存在问题,提出了一种用硫铁矿分解磷石膏的方法. 为了实现该工艺的工业化利用,探究了磷石膏内二氧化硅和高岭土杂质对分解过程的影响. 利用Factsage7.0热力学软件,计算了FeS-CaSO₄体系在加入二氧化硅或高岭土后的平衡相图,探讨了加入杂质后可能发生的副反应. 进行了杂质对分解过程影响的实验,并对产品进行SO₃分析及XRD表征. 研究结果表明,SiO₂或高岭土的加入使得FeS和CaSO₄在低温区就能发生反应,提高了反应体系的脱硫率,促进了硫酸钙的分解,并且杂质含量越高,硫酸钙分解率越高. 该研究结果有利于硫铁矿还原分解磷石膏制备硫酸工艺的推广应用.     

Preparation of BN／SiO2 ceramics by PIP method

The precursor infiltration and pyrolysis(PIP) method for preparation of BN/SiO2 composites was used to improve mechanical properties, dielectric properties and feasibility of high temperature dielectric parts with large dimensions and complex shapes. In the processing procedure, the porous BN ceramic matrix was first successfully prepared by compacting the mixed powders of B and BN and then sintering them at a certain temperature under normal pressure of N2. The polycarbosilane(PCS) solution was vacuum infiltrated into porous BN ceramics at the room temperature and then at 800℃ in the air to depolimerize out amorphous SiO2, and sintered further at 1 300℃ in N2 to get BN/SiO2 composites. The microstructure of materials was studied by means of X-ray diffraction and electron probe micro analysis. The thermo-decomposition mechanism of PCS was investigated by a TG-DTA and infrared (IR) spectrum analysis. The flexural strengths were measured by the three-point bending method. The dielectric constant and the loss tangent were measured by the wave-guide method. The results show BN/SiO2 composites were fabricated. The obtained composites posses a flexural strength of 61.96 - 93.31 MPa, the dielectric constant in the range of 3.50 - 3.78 and the order of magnitude of the loss tangent at 10^-3 , which are good for the high tempera turedielectric parts with large size and complex shapes.     

Effects of oxidation treatment on properties of SiO2f/SiO2-BN composites

The silica fiber reinforced silica and boron nitride-based composites (SiO_2f/SiO₂-BN) were prepared firstly via the sol-gel method and then the urea route, and the effects of oxidation treatment on the component, structure, mechanical and dielectric properties of the composites were investigated. The results show that the oxidation treatment at 450 °C will not impair the structure of boron nitride, and carbon is the main impurity with the excessive urea. The density of SiO_2f/SiO₂-BN composites is 1.81 g/cm³, and the flexural strength and elastic modulus are 113.9 MPa and 36.5 GPa, respectively. After oxidation treatment, the density varies to 1.80 g/cm³, and the flexural strength and elastic modulus are decreased to 58.9 MPa and 9.4 GPa, respectively. The mechanical properties of the composites are severely damaged, but they still exhibit a good toughness. The composites show excellent dielectric properties with the dielectric constant and loss tangent being 3.22 and 0.003 9, respectively, which indicates that the oxidation treatment is ineffective to improve the dielectric properties of SiO_2f/SiO₂-BN composites.     

茂金属SiO2的载体化研究(Ⅲ) ——茂金属载体催化剂用于乙烯均聚

用3种茂金属载体催化剂SiO     

Densification and sintering dynamics of 10NiO-NiFe2O4 composites doped with CaO

The effects of CaO content in the range from 0 to 4.0%, and sintering temperature on the phase composition, relative density and electrical conductivity of 10NiO-NiFe2O4 composites doped with CaO were studied. The results show that there is no change of structure for NiO or NiFe2O4; there is apparent oxygen absorbing and releasing behavior during the heating process in air for 10NiO-NiFe2O4 composites. Introduction of CaO can accelerate the densification of 10NiO-NiFe2O4 composites. The maximum value of relative density is 98.75% for composite doped with 2.0% CaO and sintered at 1 200 ℃, which is beyond about 20% for the undoped composites. The sintering activated energy of sample containing 2% CaO decreases by 15.87 kJ/mol, compared with that of the undoped sample.     

Effect of nucleating agents on microstructure and mechanical properties of SiO2-Al2O3-ZrO2 glass-ceramics

SiO2-Al2O3-ZrO2 glasses with different nucleating agents were crystallized under special processing schedule. The microstructure and mechanical properties of the glass-ceramics in SiO2-Al2O3-ZrO2 system were investigated by differential scanning calorimetry, scanning electron microscopy, X-ray diffraction and three-point bending method. The results show that ZrO2 is not an effective nucleating agent in SiO2-Al2O3-ZrO2 system, while TiO2 is effective for the separation of spinel, and P2O5 facilitates solubility of ZrO2 in glass and crystallization. The main crystalline phases of the glass-ceramics are spinel, anorthite and tetragonal zirconia. With the increase of ZrO2 content in the glass, glass-ceramics show higher bending strength （120 MPa） than others.