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1.
在90℃含Cl-碱性溶液中所研究钢种的电化学行为表明:00Cr18Ni5Mo3Si2(18-5)双相不锈钢耐一般腐蚀和孔蚀性能较0Cr18Ni9Ti(18-STi)奥氏体不锈钢更佳.碱液中的游离NH3、CO32-和HCO3-有缓蚀作用,S2-促使材料活化.EDAX、XPS及TEM分析结果表明:两种不锈钢的表面膜均为多价的复杂氧化物膜,以CrOOH、Cr2O3为主要成分.18-5钢表面膜中Cr富集程度较18-8Ti钢高,膜的致密度及稳定性亦高,膜中的MoO3能有效提高钢的耐孔蚀性能.  相似文献   

2.
化学镀Ni—Cr—P合金镀层在NaCli溶液中的耐蚀性   总被引:6,自引:0,他引:6  
用电化学方法研究了化学镀Ni-Cr-P合金镀层在3.5%NaCl溶液中的耐蚀性,结果表明Ni-Cr-P镀层与Ni-P镀层的阳极极化曲线形状相似,自腐蚀电位正移150mV以上,自腐蚀电流降低近3倍,在钝化区的阳极是约1个数量级,镀层的耐蚀性提高。  相似文献   

3.
一种化学复合镀层的研制及其耐腐蚀性研究   总被引:18,自引:0,他引:18  
研究了以纳米材料CeO2作为分散微粒的化学复合镀Ni-P-CeO2,复合镀层制备工艺,研究分析了镀层的表面形貌,对镀层的耐腐蚀性能进行了试验,结果控制温度在88~95℃,CeO2添加量为5~15g/L在适量稳定剂和表面活性剂共存的条件下,采用间歇搅拌方式能够镀覆表面质量良好的Ni-P-CeO2复合镀层,镀层表面光洁度高,对10%NaCl溶液和1%H2S气体腐蚀能力较强。  相似文献   

4.
利用XPS法研究了化学镀Ni-Cu-P非晶态合金在140℃、PH=5.0、CO2饮和Na2SO4溶液中片于不同电位下的表面膜组成。结果表明,处于不同电位下的Ni-Cu-P合金表面膜中皆有富P和富Cu现象发生,是膜中Ni选择性溶解的结果。H2PO2^-和HPO3^2-吸附层的存在是合金发生钝化的原因。  相似文献   

5.
电镀防护性锌基合金镀层钝化膜的耐蚀性   总被引:6,自引:0,他引:6  
防护性锌基合金镀层钝化膜的耐蚀性比锌镀层钝化膜提高2-4倍。XPS及AES分析表明,合金镀层钝化膜与锌镀层钝化膜均由CrO3、Cr2O3、Zn(OH)2、ZnO及H2O等组成,并且CrO3/Cr2O3的相对含量和Zn(OH)2/ZnO相对含量也基本相同,它们的区别在于,合金镀层钝化膜中总铬量较高,膜层完整、致密,镀层/钝化膜界面存在铁系金属的富集层,这是锌基合金镀层钝化膜具有高耐蚀性的主要原因。  相似文献   

6.
化学复合镀制备高活性节能NiCo2O4电极   总被引:1,自引:0,他引:1  
在贱金属铁基表面化学镀Ni-Co-P,然后通过化学复合镀制得Ni-Co-P-A12O3底层,复合镀层用NaOH溶液浸出,可制得新型Ni-Co-P微孔活性中间导参中间导地涂覆匹配性较好的NiCo2O4表面活性层,该表面活性层由一定浓度配比的Ni(NO3)2和Co(NO3)2通过高温热解而成。 射结果表明表面活性层是由NiCo2O4组成,不存在NiO和Co3O4的独立相。这种新型表面活性层用于碱性水电  相似文献   

7.
研究了发动机活塞环表面化学沉积Ni-P非晶镀层及其热处理工艺。结果表明,整个工艺过程控制稳定,化学镀Ni-P活塞环可以取代镀Cr环。  相似文献   

8.
研究了铬含量相当,镍含量分别为18wt%和39wt%的两种Fe-Ni-Cr合金在H2S/H2/CO2混合气氛中于600℃的腐蚀动力学产物层结构。镍含量不同使腐蚀产物结构上有差异;18wt%Ni合金的外腐蚀层为FeS,其下是FeCr2S4和Cr3S4;而39wt%Ni合金的腐蚀产物外层是疏松多孔,呈黑色粉状的(Ni,Fe)S,其下也是FeCr2S4与Cr3S4;而39wt%Ni合金的腐蚀产物外层是疏  相似文献   

9.
ZL104合金表面化学镀镍磷合金层的研究   总被引:5,自引:1,他引:4  
在ZL104合金表面上进行Ni-P与Ni-Cu-P化学镀,以提高ZL104合金材料的耐蚀性与耐磨性。结果表明:化学镀可以显著提高ZL104合金表面的硬度,并改善其在5%NaCl溶液中的耐蚀性;在200~520℃温度下热处理后,镀层的硬度显著提高,但耐蚀性略有降低,这可能与镀层中的析出物Ni3P析出有关。  相似文献   

10.
化学镀Ni-P合金中无机盐加速剂的影响   总被引:5,自引:1,他引:4  
研究了在化学镀NiP合金镀层时,采用无机盐复合加速剂降低镀液温度、提高沉积速度的方法。结果表明,在普通化学镀NiP合金镀液中添加无机盐复合加速剂HN3(3份(NH4)2SO4与2份K2CO3的混合物)30g/L,在80℃下施镀,其沉积速度可达15μm/h,比不含该加速剂时提高40%左右,镀液寿命可达5个周期以上,镀层外观光亮,结晶细致。  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

13.
吴玉梅  熊晓云  靳蓉  孙敬民  杨林  罗晓星 《金属学报》2005,10(10):1100-1103
目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。  相似文献   

14.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

15.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

16.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

17.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

18.
An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.  相似文献   

19.
A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.  相似文献   

20.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.  相似文献   

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