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Laser Cladded TiCN Coatings on the Surface of Titanium

Y.L. Yang , D. Zhang , H.S. Kou , C.S. Liu , null , null , null , null , null , null , null , null , null , null , null , null , null

金属学报(英文版)

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.

关键词: laser cladding , null , null

Ba在C2S-C3S矿物相中固溶机理探讨

陈树东 , 项建明 , 王晓翠 , 洪笑

硅酸盐通报

以Ca(OH)2、SiO2、Fe2O3、Al2O3化学纯为原料,分别掺入不同质量分数的Ba(OH)2制备不同矿物相组成的熟料相,运用化学分析、XRD、SEM、水化热测试方法,研究掺Ba(OH)2后熟料相中硅酸三钙-硅酸二钙(C3S-C2S)混合相组成、晶型、新相生成的变化规律.结果表明:Ba(OH)2一定程度上削弱C3S形成,且稳定β-C2S形成效应明显,矿物相体系中α'-C2S、α-C2S量减少并转换为β-C2S,掺量大于2.5％后有新相Ba0.48 Ca1.52SiO4形成;Ba(OH)2掺入促使矿物相中C2S相明显增多,晶粒整体尺寸变小,边界变圆润;随Ba(OH)2掺量递增,熟料样的水化速率呈持续减小的趋势变化.

关键词: C3S相 , β-C2S , 水化速率 , 水化

P2O5对C6A4MS-C2S-C4AF系中β-C2S稳定作用研究

马德伟 , 杨利群 , 徐先宇

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2001.02.020

本文研究了C6A4MS-C2S-C4AF系中R2O5对β-C2S的稳定性问题.结果表明:P2O5的掺入能有效抑制β-C2S转变为γ-C2S,稳定β-C2S;少量P2O5对C6A4MS的形成无抑制作用.

关键词: P2O5 , C6A4MS-C2S-C4AF系统 , β-C2S稳定

C-S-H 凝胶及其研究方法

杨南如

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2003.02.011

在分析C-S-H凝胶的复杂性和特征的基础上,就测定它的化学组成、C-S-H凝胶中[SiO4]4-四面体的聚合度及其结构的化学和物理的方法作了简要介绍.现代各种测试方法的出现和使用,对C-S-H凝胶的组成和集中[SiO4]4-四面体的聚合结构有了较为完整的概念.

关键词: C-S-H凝胶 , 化学组成 , 凝胶结构 , 测定方法

Q相-C2S-C4AF-C12A7系列水泥形成的研究

姜奉华 , 徐德龙

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2004.06.006

通过研究Q相与C2S和Q相与C4AF的共存条件,构造Q相-C2S-C4AF水泥系统,对此系统水泥形成条件进行研究.研究表明:Q相与C2S和Q相与C4AF能够共存,可以组成Q相-C2S-C4AF-C12A7水泥系统.在Q相-C2S-C4AF-C12A7水泥系统中,Q相在1270℃开始生成,随着温度的升高,Q相的生成量逐渐增大;采用V2O5对β-C2S具有较好的稳定作用.随着C4AF量的增加,Q相的量也在增加,同时,烧成温度降低.

关键词: Q相 , Q相-C2S-C4AF水泥 , 形成条件 , 抗压强度

C2S前导物对C3S形成及活化能的影响

管宗甫

硅酸盐通报

用工业原料在不同温度预合成C2S(2CaOSiO2)为主要矿物的前导物,并以该前导物为基础,补入适量的钙,在不同温度下二次烧成水泥熟料.结果显示:采用1250℃、1300℃和1350℃预合成的C2S前导物配料二次烧方法,有利于熟料在低温下烧成,在1350℃左右实验熟料样品中游离氧化钙即可小于1.0％.相应C3S在熟料体系中的表观形成活化能相比不同配料烧成的对比组明显降低,而不同温度制备的前导物配料,C3S在熟料体系中的形成活化能相差无几.

关键词: C2S前导物 , 二次烧成 , 水泥熟料 , 硅酸三钙 , 活化能

Molecular Electrical Conductor Ni(C_3S_5)_2

Hong LEI (Dept. of Electronic Engineering , Shandong University , Jinan 250100 , China)Qi FANG and Minhua JIANG (Institute of Crystal Materials , Shandong University , Jinan 250100 , China)Yueming SUN (Dept. of Chemistry Southeast University Nanjing 210093 , Chi

材料科学技术（英文）

The molecular based electrical conductor Ni(C3S5)2 has been prepared and its conductivity has been measured from room temperature down to 60 K. Above 167 K Ni(C3S5)2 exhibits a semiconductive behaviour, below this temperature it turns to exhibit metallic conductivity. Based on a tight-binding energy band calculation, an expression for the number of conducting electrons has been deduced. The calculated conducting activation energy is quite well in accordance with the measuring value.

关键词:

Q相-C2S系统中V2O5对β-C2S稳定性的研究

杨利群 , 祝名伟 , 封汉昌 , 徐先宇

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2000.03.016

本文研究了Q相-C2S配合料中V2O5对β-C2S的稳定性问题.结果表明,微量V2O5可以稳定β-C2S,使Q相与β-C2S可在常温下共存;Q相-C2S配合料中V2O5/C2S在0.8～1.0%的范围内V2O5稳定β-C2S的效果最好.

关键词: Q相 , C2S , V2O5 , CaO-MgO-Al2O3-SiO2系统

Q相-C2S-C4AF-C12A7水泥作为膨胀剂的研究

姜奉华 , 徐德龙

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2005.04.026

采用普通硅酸盐水泥作为基体、Q相-C2S-C4AF-C12A7水泥作为膨胀剂、加入少量石膏的条件下进行试验研究.研究表明:Q相-C2S-C4AF-C12A7水泥能够作为膨胀组分,调节Q相-C2S-C4AF-C12A7水泥和SO3的量,能够得到所要求的膨胀水泥.从DTA和XRD得知,其膨胀源主要是钙矾石(AFt),它形成的速度及数量,可以通过控制Q相-C2S-C4AF-C12A7水泥和SO3的量来实现.

关键词: 膨胀水泥 , 膨胀剂 , 微观分析 , 钙矾石

B2O3和CaF2对C3S-C2.75B1.25A3S-C2S-C3A水泥熟料矿物体系力学性能影响

芦令超 , 常钧 , 沈业青 , 程新 , 刘韩星 , 袁润章

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2005.02.023

研究了B2O3和CaF2对C3S-C2.75B1.25A3S-C2S-C3A熟料矿物体系的组成、结构与力学性能的影响.研究结果表明:在该熟料体系中C3S,C2.75B1.25A3S,C2S和C3A的适宜含量分别为50%,10%,25%和15%,B2O3和CaF2的适宜掺量为2%和1.5%.在最佳组成和制备工艺条件下,合成的阿利特-硫铝酸钡钙水泥的1d,3d和28d抗压强度分别达到18MPa,48MPa和95MPa以上,展现了良好的早期力学性能.同时,掺加CaF2能有效降低熟料中游离氧化钙的含量,促进阿利特在低温条件下形成.利用SEM-EDS,XRD等测试手段对熟料的组成、结构及性能进行了分析.

关键词: 阿利特硫铝酸钡钙 B2O3 CaF2

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