scholarly journals ANALYSIS OF Nb - Ni AND V - Ni BASED MEMBRANE CHARACTERISTICS

Author(s):  
Римма Михайловна Белякова ◽  
Эльмира Джумшудовна Курбанова ◽  
Валерий Анатольевич Полухин

Для получения сверхчистого водорода мембранной технологией вместо дорогостоящих сплавов Pd рассмотрены более дешёвые на основе металлов Nb и V . Накапливаемый в матрицах обычных мембран водород формирует специфические полиэдрические плотноупакованные гидридные образования особенно с повышение температур от 473 до 673 К и риском разрушения мембран. Благодаря легированию титаном этих сплавов повысились рабочие характеристики мембран: диффузия и проницаемость водорода, прочность, износоустойчивость и термостабильность. В кристаллических аналогах проблема образования гидридов также была решена повышением концентрации Ti с формированием эвтектических фаз в тройных составах сплавах, например, NbTiNi и VTiNi. С формированием в указанных составах соединений NiTi и NiTi образование гидридов блокируется даже при нагреве, благодаря устойчивым процессам водородной селективности. To obtain ultrapure hydrogen by membrane technology, instead of expensive membranes made of Pd alloys, cheaper ones based on metals (Nb - Ni) and (V - Ni) are considered. Due to alloying of these Ti alloys, the performance of the membranes increased - diffusion and permeability of hydrogen, wear resistance and thermal stability, exceeding the Pd alloys. For crystalline analogs, the problem was also solved by increasing the Ti concentration with the formation of eutectic phases in ternary alloy compositions (NbTiNi and VTiNi). Hydrogen accumulated in membrane matrices forms specific polyhedral eutectic TCP hydrides up to phase transitions, and upon cooling from 673 to 303K under conditions of thermal expansion from 473 to 673K, it increases the temperature of P-hydride formation and forms NiTi and NiTi compounds, which stabilize and protect nano- and crystalline membranes from brittle destruction.

Alloy Digest ◽  
1998 ◽  
Vol 47 (4) ◽  

Abstract Deltalloy 4032 has good machinability and drilling characteristics when using single-point or multispindle screw machines and an excellent surface finish using polycrystalline or carbide tooling. The alloy demonstrates superior wear resistance and may eliminate the need for hard coat anodizing. Deltalloy 4032 is characterized by high strength and a low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion and wear resistance as well as machining and surface treatment. Filing Code: AL-347. Producer or source: ALCOA Wire, Rod & Bar Division.


Alloy Digest ◽  
1960 ◽  
Vol 9 (2) ◽  

Abstract RED X-20 is a heat treatable hypereutectic aluminum-silicon alloy with excellent wear resistance and a very low coefficient of thermal expansion. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-89. Producer or source: Apex Smelting Company.


2019 ◽  
pp. 175-181
Author(s):  
A. I. Kovtunov ◽  
T. V. Semistenova ◽  
A. M. Ostryanko

The paper offers technology of argon-arc surfacing with titanium wire in order to form heat and wear resistant coating based on the titanium cuprides. The influence of surfacing modes on the chemical compound and structure of formed coatings is determined. The wear resistance and heat resistance at 600°C and 800°C were researched for copper–titanium coating with 8–63% titanium.


2021 ◽  
Vol 11 (10) ◽  
pp. 4603
Author(s):  
Soyoung Kim ◽  
Karam Han ◽  
Seonhoon Kim ◽  
Linganna Kadathala ◽  
Jinhyeok Kim ◽  
...  

Today, the most common way of laser sealing is using a glass frit paste and screen printer. Laser sealing using glass frit paste has some problems, such as pores, nonuniform height, imperfect hermetic sealing, etc. In order to overcome these problems, sealing using fiber types of sealant is attractive for packaging devices. In this work, (70-x)V2O5-5ZnO-22BaO-3B2O3-xM(PO3)n glasses (mol%) incorporated with xM(PO3)n concentration (where M = Mg, Al, n = 2, 3, respectively) were fabricated and their thermal, thermomechanical, and structural properties were investigated. Most importantly, for this type of sealing, the glass should have a thermal stability (ΔT) of ≥80 °C and the coefficient of thermal expansion (CTE) between the glass and panel should be 1.0 ppm/°C. The highest thermal stability ΔT of the order of 93.2 °C and 112.9 °C was obtained for the 15 mol% of Mg(PO3)2 and Al(PO3)3 doped glasses, respectively. This reveals that the bond strength and connectivity is more strongly improved by trivalent Al(PO3)3. The CTE of a (70-x)V2O5-5ZnO-22BaO-3B2O3-xAl(PO3)3 glass system (mol%) (where x = 5–15, mol%) is in the range of 9.5–15.5 (×10−6/K), which is comparable with the CTE (9–10 (×10−6/K)) of commercial DSSC glass panels. Based on the results, the studied glass systems are considered to be suitable for laser sealing using fiber types of sealant.


2015 ◽  
Vol 652 ◽  
pp. 287-291 ◽  
Author(s):  
Xiaojuan Li ◽  
Zengzhe Xi ◽  
Peng Liu ◽  
Wei Long ◽  
Pinyang Fang

2008 ◽  
Vol 34 (4) ◽  
pp. 436-442 ◽  
Author(s):  
M. I. Georgievskaya ◽  
R. S. Bubnova ◽  
S. K. Filatov ◽  
V. L. Ugolkov

2007 ◽  
Vol 539-543 ◽  
pp. 3261-3266 ◽  
Author(s):  
Iulian Radu ◽  
Dong Yang Li

The near-equiatomic TiNi alloy has been demonstrated to possess high wear resistance, which largely benefits from its pseudoelasticity (PE). However, the PE occurs only in a small temperature range, which makes the wear resistance of this alloy unstable as temperature changes, caused by environmental instability or frictional heating. Therefore, enlarging the working temperature of PE could considerably improve this alloy as a novel wear-resistant material. One possible approach is to develop a self-built temperature-dependent internal stress field by taking the advance of the difference in thermal expansion between the pseudoelastic matrix and a reinforcing phase. Such a T-dependent internal stress could adjust the martensitic transformation temperature to respond changes in environmental temperature so that the temperature range of PE could be enlarged, thus leading to a wide temperature range in which the minimum wear loss is retained. Research was conducted to investigate effects of an added second phase having a negative thermal expansion (NTE) coefficient on the wear resistance of a near-equiatomic TiNi alloy. It was demonstrated that the temperature range of this modified material in which the wear loss dropped was enlarged. In addition, the wear resistance of such a TiNi-matrix composite was on one order of magnitude higher than that of unmodified TiNi alloy.


2021 ◽  
Vol 13 (4) ◽  
pp. 556-562
Author(s):  
Niu Zhang ◽  
Ming-Yi Wu ◽  
Ya-Ming Liu ◽  
Meng-Jie Yang ◽  
Ming-Ju Chao ◽  
...  

The HfV2O7/HfMo2O8 composite were prepared in situ. The phase, structure and thermal expansion property were analyzed. The results indicate the composite consist of cubic HfV2O7 and hexagonal HfMo2O8. The two types of structures were coexisted and mixed uniformly, and interacted with each other. The mutual nested structure suppressed the formation of 3×3×3 superstructure in HfV2O7 (RT) introduced by the reaction in situ. The promoted coupled rotation of quasi-rigid polyhedron units could enhance the negative thermal expansion (NTE) property. The HfV2O7/HfMo2O8 composite exhibits excellent NTE property from 250 to 673 K (at least) with CTE -3.09 × 10-6 K-1. The good NTE property and thermal stability over a wide temperature range, especially near the RT range, bring a good potential application in designing zero thermal expansion materials.


1967 ◽  
Vol 70 (10) ◽  
pp. 1633-1637 ◽  
Author(s):  
Masanori NAGATANI ◽  
Makoto HAYAMA ◽  
Noboru YAMAZOE ◽  
Tetsuro SEIYAMA

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