共查询到20条相似文献,搜索用时 78 毫秒
1.
钛合金表面等离子喷涂制备ZrO2—Ti系功能梯度涂层 总被引:8,自引:1,他引:8
研究了等离子喷涂法制备ZrO2-Ti系功能梯度涂层。结果表明,采用等离子喷涂工艺制备功能梯度涂层是可行的,涂层与基体除以机械咬合方式结合外,还存在着少量冶金化学化学反应结合,添加Ni/Al和SiO2有助于提高涂层的结合强度。 相似文献
2.
研究了等离子喷涂法制备ZrO2Ti系功能梯度涂层。结果表明,采用等离子喷涂工艺制备功能梯度涂层是可行的,涂层与基体除以机械咬合方式结合外,还存在着少量冶金化学反应结合,添加Ni/Al和SiO2有助于提高涂层的结合强度 相似文献
3.
4.
在8%Y2O3稳定的ZrO2陶瓷涂层中添加SiO2,使陶瓷涂层的抗热震性能得到提高,这主要是SiO2的加入使涂层抗热震前后的表面形貌发生了很大的变化。由于ZrO2与SiO2热膨胀系数不同,使涂层利于产生细微的网状裂纹,增加了微裂纹密度和孔隙,从而降低了涂层的弹性模量,释放了涂层中的应力,使涂层的抗热震失效能力得到提高。其中,SiO2加入量为3%(质量分数)效果最佳,过量的加入,会使孔洞加大,促进裂纹的扩展、断裂,不利于提高涂层的抗热震性能。 相似文献
5.
采用SEM,EPMA和热震方法,研究了CeO2添加剂对等离子喷涂ZrO2i涂层抗热震性能的影响。结果表明:当CeO2由0增加到9.0%(质量分数,下同)时,涂层的抗热震起裂次数和失效次数分别由32次和46次增加到76次和105次;继续增加CeO2,涂层的抗热震性能急剧下降。ZrO2 9.0?O2涂层在热循环中形成的网状微裂纹,不仅可降低涂层中的应力,也可提高涂层开裂的临界温差,从而可改善其抗热震性能。 相似文献
6.
TiAlCr涂层对TiAl金属间化合物抗熔融硫酸盐热腐蚀的影响 总被引:2,自引:1,他引:1
研究了溅射TiAlCr 涂层对TiAl 金属间化合物抗硫酸盐热腐蚀性能的影响。结果表明,850 ℃时,90 % Na2SO4 + 10 % K2SO4 中Ti50Al 和Ti24Al14Nb3V 都遭受严重热腐蚀。TiAlCr 涂层能大大改善TiAl 金属间化合物的抗热腐蚀性能。带Ti50Al10Cr 涂层的Ti50Al 表面形成一层完整致密的Al2O3 膜, 涂层与基材之间无明显互扩散。带Ti50Al10Cr 涂层的Ti24Al14Nb3V 表面虽然也形成Al2O3 膜, 但在其上面长出一些TiO2 瘤。这可能是涂层与基材之间的互扩散导致涂层中Ti 含量增加,Al 含量减少而生成TiO2 的结果。将涂层成分调整为Ti50Al20Cr 后, 带Ti50Al20Cr 涂层的Ti24Al14Nb3V 表面生成了连续的Al2O3 膜, 其抗热腐蚀性能良好。 相似文献
7.
等离子喷涂Al2O3与Cr2O3涂层性能的研究 总被引:3,自引:1,他引:2
对等离子喷涂Al2O3、Cr2O3涂层耐蚀性和耐磨性的试验研究表明,在3.5%NaCl介质中,Al2O3涂层耐蚀性优于Cr2O3涂层;在滑动磨损条件下,Cr2O3涂层的耐磨性优于Al2O3涂层。 相似文献
8.
9.
运用微弧等离子喷涂制备了碳化硅晶须(SiCw)掺杂部分稳定ZrO2(YPSZ)复合热障涂层(CTBCs),对涂层进行了显微组织观察、EDS分析、XRD分析和抗热震性能试验.喷涂过程中,复合粉末里的部分SiCw在高温下分解产生的气体夹杂在熔融的颗粒内形成气孔,另一部分沉积在涂层中起到降低热应力和钉扎、桥联作用.结果表明,随着粉末中SiCw含量的增加,复合陶瓷层的孔隙率呈增大趋势;复合涂层的抗热震性能优于单纯氧化锆涂层,SiCw含量为20%的复合涂层的抗热震性能最优. 相似文献
10.
采用等离子喷涂设备在H13热作模具钢表面制备含有不同质量分数TiO2的Al2O3纳米陶瓷复合涂层。采用X射线衍射仪(XRD)、高温氧化试验、热震试验等手段研究等离子喷涂纳米涂层的相组成及其性能。结果表明,等离子喷涂使α-Al2O3转变为亚稳态的γ-Al2O3相,喷涂后涂层中Al2O3由α-Al2O3相和γ-Al2O3相组成,TiO2仍以金红石相存在。纳米AT20涂层比其他涂层具有更好的抗氧化性能;与其他涂层相比,纳米AT13涂层具有最佳的抗热震性能。 相似文献
11.
The new phases KFe2(SeO2OH)(SeO3)3 and SrCo2(SeO2OH)2(SeO3)2 have been synthesized under low-hydrothermal conditions and their structures were determined by single-crystal X-ray methods. Both compounds are monoclinic; KFe2(SeO2OH)(SeO3)3: space group P2, A = 9.983(4), B = 5.270(1), C = 10.614(4) Å, β = 97.42(2)°, V = 553.7 Å3, Z = 2; SrCo2(SeO2OH)2(SeO3)2: space group P2ln, A = 14.984(2), B = 5.286(1), C = 13.790(2) Å, β = 94.72(1)°, V = 1088.5 Å3 , Z = 4. The refinements converged to R-values of 2.9 and 3.6% respectively.
The atomic arrangement in KFe2(SeO2OH)(SeO3)3 and SrCo2(SeO2OH)2(SeO3)2 is based on isolated MO6 octahedra (M = Fe3+, Co2+), which are corner-linked via trigonal pyramidal selenite groups to a framework structure. Interstitials are occupied by potassium or strontium atoms in ten- or eight-coordination respectively, and by the lone-pair electrons of the Se4+ atoms. Both compounds are not isotypic but are closely related and may be interpreted as different distortions of an idealized structure type in space group P2/m, which was modelled for a theoretical compound SrFe2(SeO3)4 by distance least squares refinement (program ). 相似文献
12.
M. Hoch 《Journal of Phase Equilibria and Diffusion》1996,17(4):290-301
We applied our model to the enthalpy of mixing data of the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen
ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates.
The same applies to the CaO-SiO2, CaO-Al2O3, PbO-B2O3, PbO-SiO2, ZnO-B2O3, and ZnO-SiO2 systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure
of the liquid.
Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of
the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct
solid-solid calorimetry. 相似文献
13.
Wang Haiping Lu Tiecheng Wang Xuemin Ge Fangfang Cao Linhong Zhang Hongliang Li Chunhong Yu Xiaohan Ju Xin Wu Weidong 《Corrosion Science》2011,(3):1115-1119
LiBH4 films were prepared by pulsed laser deposition using a LiB target in a background pressure of hydrogen. The corrosion characteristics of LiBH4 films were measured by exposing them to a gas mixture of CO2/H2O/O2/N2 at ambient temperature for 1–24 h. Scanning electron microscopy images show some cracks on the surface of corrosion films, which could act as easy paths for H2O and CO2 to further react with Li+ and B3+. The X-ray photoelectron spectroscopy results and theoretical analysis show that LiBH4 tends to react with H2O and CO2 to form Li2B4O7, Li2CO3 and LiOH during the corrosion process. 相似文献
14.
Hui Zhang Liang Fang Mei-Bo Tang Hao-Hong Chen Xin-Xin Yang Xiangxin Guo Jing-Tai Zhao Yuri Grin 《Intermetallics》2010,18(1):193-198
High density polycrystalline CaCd2Sb2 and EuCd2Sb2 intermetallics are synthesized by Spark Plasma Sintering and their thermoelectric properties are investigated. X-ray diffraction measurements reveal both materials have a structure in space group, containing a small amount of CdSb as a second phase. Thermoelectric measurements indicate both are p-type conductive materials. The figure of merit value of CaCd2Sb2 is 0.04 at 600 K and that of EuCd2Sb2 is 0.60 at 617 K. Theoretical calculations show that CaCd2Sb2 is a degenerate semiconductor with a band gap of 0.63 eV, while EuCd2Sb2 is metallic with DOS of 13.02 electrons/eV. For deeper understanding of the better thermoelectric properties of EuCd2Sb2, its low temperature magnetic, transport and heat capacity properties are investigated. Its Nèel temperature is 7.22 K, convinced by heat capacity anomaly at 7.13 K. Hall effect convinced that it is a p-type conductive material. It has high Hall coefficient, high carrier concentration and high carrier mobility of +1.426 cm3/C, 4.38 × 1018/cm3 and 182.40 cm2/Vs, respectively. They are all in the magnitude of good thermoelectric materials. The Eu 4f level around Fermi energy and antiferromagnetic order may count for the better thermoelectric properties of EuCd2Sb2 than that of CaCd2Sb2. 相似文献
15.
Zhong-jia Huang 《Surface & coatings technology》2008,202(14):3208-3214
The MoS2 powders were coated with Al2O3 (5 wt.%) through controlling hydrolysis of Al (NO3)3·9H2O. MoS2 powder coated with Al2O3 was written as MoS2/Al2O3 hereinafter. MoS2/Al2O3 powders were put into Ni plating electrolyte bath. Cetyltrimethylammonium bromide (CTAB) — the surfactant was also put into the bath. The experiment proves that MoS2/Al2O3 particles were absorbed onto the Ni plate. The amount of MoS2/Al2O3 deposited on Ni plate rises with the increasing concentration of MoS2/Al2O3 in the bath. The microhardness, micro-surface, phase and the tribological property of the MoS2/Al2O3 multi-plating coating were measured and analyzed. The performances of microhardness and wear resistance of the Ni-MoS2/Al2O3 composite are better than those of Ni-MoS2 composite. 相似文献
16.
A. V. Morozkin 《Journal of Alloys and Compounds》2003,360(1-2):L7-L8
Results of a powder X-ray diffraction investigation of new ternary compounds are reported. The compounds Y6CoBi2 [a=0.8312(1) nm, c=0.4144(1) nm], Ho6CoBi2 [a=0.8246(2) nm, c=0.4095(1) nm], and Tm6CoBi2 [a=0.8155(2) nm, c=0.4066(1) nm] crystallize in the hexagonal Zr6CoAs2-type structure (space group P6b2m No. 189). The Zr6CoAs2-type structure is a superstructure of the Fe2P-type structure. 相似文献
17.
We have investigated the magnetic properties and the 155Gd Mössbauer spectra of the ThCr2Si2-type compounds GdNi2Sb2, GdCu2Sb2 and GdAl2Ga2. These three compounds were found to order antiferromagnetically, with TN=6.5 K, 15.8 K, and 42.4 K respectively. The electric field gradient V22 derived from the quadrupole splitting of the Mössbauer spectra gives rise to a sign change at the end of the T3d series in GdT2Sb2, as was observed previously also for the corresponding compounds with Si and Ge. This behaviour was explained in terms of decreasing hybridization between the Gd valence electron states and the d electron states of the T atoms. 相似文献
18.
探究了使用大气等离子喷涂设备制备适合热喷涂使用的球形CaF2/BaF2共晶粉末的可能性。68%BaF2、32%CaF2粉末(质量分数)经过1 100℃真空烧结后,形成致密的块状氟化物共晶。机械破碎后的氟化物共晶经过等离子焰流重熔后得到了球形的氟化物共晶。使用F14-1流动性和松装密度测定仪测量球化前后粉末的流动性和松装密度。采用扫描电子显微镜,XRD表征球化前后粉末的形貌和物相组成。结果表明:球化后的粉末呈现较好的球形,球化后粉末的流动性和松装密度较球化前也有较大的改善:球化后共晶粉末的流动时间为55.20s/50g,松装密度为1.89g/cm3;另外,球化后共晶粉末还表现出良好的高温润滑性能:含有10%CaF2/BaF2共晶(质量分数)的镍基涂层在600℃和800℃的平均摩擦因数都小于0.3。 相似文献
19.
Mineaki Matsumoto Hiroshi Takayama Daisaku Yokoe Kazuo Mukai Hideaki Matsubara Yukio Kagiya Yuuji Sugita 《Scripta materialia》2006,54(12):2035-2039
The effects of La2O3 addition on thermal conductivity, phase stability and thermal cycle life of Y2O3 stabilized ZrO2 plasma sprayed coatings were investigated. Although low thermal conductivity as well as high resistance to sintering was achieved by La2O3 addition, it tended to also result in lower phase stability and thermal cycle life of the coatings. Optimization of the composition and structure of the coatings improved these properties, and the optimized coatings showed prolonged thermal cycle life. 相似文献
20.
The reactions for LiNH2 under a H2 and an Ar flow were investigated, respectively. The results showed that LiNH2 can be converted into LiH and NH3 by reacting with H2 under a H2 flow condition, whereas LiNH2 is converted into Li2NH and NH3 by decomposition under an Ar flow. Moreover, the reaction between LiNH2 and H2 can be accelerated by mixing LiNH2 with LiH as well as doping LiNH2 with TiCl3. The confirmation of reaction between LiNH2 and H2 is helpful for the deeper insight in the systems of Li–N–H and Li–Mg–N–H for hydrogen storage materials. 相似文献