Thermal Equilibrium Diagram Research Articles

Nano-particle synthesis of titanium oxides from ilmenite in a thermal plasma reactor

Nano-particle of titanium oxides was synthesised from the precursor ilmenite powder in an argon plasma jet at atmospheric pressure. The decomposition of ilmenite concentrates was investigated in a non-transferred arc thermal plasma reactor. Argon and Argon–Nitrogen were taken as plasma gases in the plasma torch. The effect of input power, plasma gases and particle size was carried out on the quality and yield of the product. Nano-powders were characterized using various techniques, viz., XRD, SEM, and TEM. Thermal equilibrium diagram was plotted to predict the thermodynamic behaviour of the system under various operating conditions. The present investigation shows significant segregation of titanium and iron-rich products in thermal plasma processing. Average particles diameters are from 10nm to 200nm.

The structure and composition of novel electrodeposited Sn–Fe and Sn–Co–Fe alloys from a flow circulation cell system

This study involved the use of a flow circulation cell, using varying circulation rates as a room temperature process (20°C). Mossbauer and XRD analysis were conducted to ascertain whether amorphous or microcrystalline structures could be obtained at 20°C using a range of current densities. Amorphous or microcrystalline structures of Sn–Fe and Sn–Co–Fe have potentially important industrial applications for energy efficient cells, for use as high performance electrodes in lithium batteries, as environmentally acceptable corrosion resistant materials and are derived from an energy efficient environmentally friendly electrolyte process which would be acceptable as an industrial process. \(^{\it 57}Fe\) and \(^{\it 119}Sn\) Mossbauer investigations supported by XRD analysis confirmed that the room temperature flow circulation cell gave rise to previously unknown non-equilibrium amorphous structures which do not occur in the corresponding thermally prepared alloys as shown in the thermal equilibrium diagrams. Mossbauer analysis shows these alloys to be both amorphous and ferromagnetic. It is shown that the flow circulation cell used at 20°C based on the environmentally friendly gluconate bath reported gives amorphous based Sn–Fe and Sn–Co–Fe alloys over a useful range of current densities facilitated by using a range of circulation rates.

Basicity-Gibbs Free Energy Relationships for Binary Alkali Silicates

In present paper there are presented such correlations for the silica-alkali systems (M2O – SiO2) where reliable thermodynamic data exists from the thermal equilibrium diagrams. It was observed that with the saturation of SiO2 tetrahedron with metal ions, the difference in basicity between the reactants is diminished, in the order SiO2 → disilicate → metasilicate → orthosilicate, and that confirms the role of driving force for these reactions of the acid-base interaction between oxides and the intermediate silicates formed. Also, there were proposed some correlations between the standard formation Gibbs free energy, (Gº298), and basicity percentage, pB, for the binary compounds from the same oxide systems. Considering the fact that for a system at equilibrium, reaction constant Kp depends on the reaction free Gibbs energy (rG0 298) and temperature, a correlation between basicity difference through basicity percentage, pB, and rG0 298 is proposed.

The Relationship between Microstructure and the Thermal Equilibrium Diagram of Au-Co Alloy Electrodeposit

An Au-Co alloy with an extensive composition range was electrodeposited from a gold sulfite and cobalt sulfate mixture. The Au-Co alloy electrodeposits were analyzed by XRD and TEM and the relationship between the phase and thermal equilibrium diagrams was investigated. The Au-Co alloy electrodeposits formed a solid solution over an extensive composition range. It was also revealed that the composition of the electrodeposited Au-Co alloy was equal to that of the quenched phase at a high temperature, about 950°C.

Ａｕ‐Ｃｏ合金めっき膜の微細構造と熱平衡状態図の関係

An Au-Co alloy with an extensive composition range was electrodeposited from a gold sulfite and cobalt sulfate mixture. The Au-Co alloy electrodeposits were analyzed by XRD and TEM and the relationship between the phase and thermal equilibrium diagrams was investigated. The Au-Co alloy electrodeposits formed a solid solution over an extensive composition range. It was also revealed that the composition of the electrodeposited Au-Co alloy was equal to that of the quenched phase at a high temperature, about 950°C.

Relationship between the Crystallographic Structure of Electrodeposited Fe-Cr Alloy Film and Its Thermal Equilibrium Diagram

Relationship between the Crystallographic Structure of Electrodeposited Fe-Cr Alloy Film and Its Thermal Equilibrium Diagram

Relationship between the Crystallographic Structure of Electrodeposited Fe-Zn Alloy Film and Its Thermal Equilibrium Diagram

The crystallographic structure and morphology of electrodeposited Fe-Cr films under different bath conditions were studied in detail by using XRD, HRTEM and SEM. The crystallographic structures of the Fe-Cr electrodeposits were also compared with the Fe-Cr thermal equilibrium diagram. The results indicated that the crystallographic structure of electrodeposited Fe-Cr alloy film gradually changed from microcrystalline to amorphous with increasing Cr content. The deposited film exists as α-Fe solid solution when the Cr compositions of deposited films are below 3.1 at%, whereas, it existed as a meta-stable crystal when the Cr compositions of deposited films are from 4.5 at% to 22.4 at%, which have not been reported up to now. The deposited films with various Cr compositions from 22.9 at% to 74.4 at% chromium exist as amorphous phase. Hence, the crystallographic structure of the electrodeposited Fe-Cr alloy film is closely related to its thermal equilibrium diagram, but does not always agree with it.

電析Ni-W合金めっき膜の微細構造と熱平衡状態図との関係

電析Ni-W合金めっき膜の微細構造と熱平衡状態図との関係

電析Ni-P合金めっき膜の微細構造と熱平衡状態図との関係

The electrodeposited Ni-P alloy films were obtained from Watts baths containing H3PO3. The crystallographic structure and morphology of electrodeposited Ni-P films were studied by using XRD, HRTEM, SEM and heat-treatment technique. The crystallographic structures of electrodeposited Ni-P alloy films was also compared with the Ni-P thermal equilibrium diagram. The X-ray diffraction patterns of Ni-P electrodeposited films with various P contents gradually changed from sharp peaks to broad peaks with increasing P contents in electrodeposited films. HRTEM observation revealed that the crystallographic structure of electrodeposited Ni-P film with 18.5 at%P content was crystalline and its crystal size was about 10 nm. Moreover, the crystalline structure was observed and the crystal size was about 3 nm in the electrodeposited Ni-P alloy film with 21.5 at%P content. However, when the film with 21.5 at%P content was heat treated, the crystalline phase did not grow and Ni3P existed alone under 300°C heat-treatment. From this result, it was clear that the crystallographic structure of Ni-P film with 21.5 at%P content was amorphous. Therefore, it can be concluded that the microcrystalline phase existed up to 19 at%P in electrodeposited Ni-P alloy film and the amorphous phase existed from 19 at% to 32 at%P.

電析Fe-W合金めっき膜の結晶学的構造と熱平衡状態図との関係

The crystallographic structure and morphology of electrodeposited Fe-W films under different bath conditions were studied in detail by using SEM, XRD and Heat-treatment method. The crystallographic structures of the Fe-W electrodeposits were also compared with the Fe-W thermal equilibrium diagram. The results indicated that the crystallographic structure of electrodeposited Fe-W alloy film gradually changed from microcrystalline to amorphous with increasing W content. The crystallographic structure of the electrodeposited Fe-W alloy film is closely related to its thermal equilibrium diagram, but does not always agree with it.

電析Fe-Zn合金めっき膜の構造と熱平衡状態図との関係

電析Fe-Zn合金めっき膜の構造と熱平衡状態図との関係

電析Ni-Sn合金めっき膜の構造と熱平衡状態図との関係

The physical properties of a plated film are directly related to its crystallographic structure. If the crystallographic structure of the film can be controlled, the physical properties can be controlled. From this reason, investigation of the crystallographic structure of the plated film are very important. In this investigation, the crystallographic structure of electroplated Ni-Sn film is studied in detail and compared with the thermal equilibrium diagram of its alloy. The structure of the plated film is seen to be closely related to the thermal equilibrium diagram. However, in the plated film a β and a γ phase which show in the thermal equilibrium diagram are not formed, and two kinds of metstable phases and a super-saturated solid solution are formed.

電析In-Sn合金めっき膜の構造と熱平衡状態図との関係

電析In-Sn合金めっき膜の構造と熱平衡状態図との関係

電析Cu-Sn合金めっき膜の構造と熱平衡状態図との関係

電析Cu-Sn合金めっき膜の構造と熱平衡状態図との関係

電析Ni-Sn合金めっき膜に現れる準安定相

We offen encounter with cases in which an amorphous or a phases which is not described in a thermal equilibrium diagram appears in an electroplated alloy film and also X-ray diffraction peaks which are not maintained in JCPDS appear in the X-ray diffraction pattern. All of theses are due to the existence of the metastable phase in the plated film. In this paper by investigating the transformation process of two kinds of metastable phases which appear in an electroplated Ni-Sn alloy film as a thermal equilibrium phase by heat treatment, the crystallographic structures of these metastable phases were characterized.

Preparation of Ni-B Amorphous Alloy Films by Electrodeposition Using a Rotating Electrode and Their Structural Changes

SummaryElectrodeposition of Ni-B group alloys was conducted using a rotary electrode. The changes in the amount of codeposited B and in the hydrogen content that arise from changes in plating conditions, and the resulting structural chnages in the films were examined The following results were obtained:1. The films prepared using a cylindrical rotating electrode contain a larger amount of codeposited B compared to those prepared in a static bath.2. When the Ni-B amorphous alloy with a B content exceeding 25 at % is prepared using a rotary electrode, the film structure after heat treatment corresponds to the structures of the intermetallic compounds Ni3B and Ni2B in the thermal equilibrium diagram.3. Although the hydrogen content of Ni-B alloy films are influenced by the current density, they correlate most strongly with the amount of codeposited B.

Formation of metastable phases by the plating method

Plating is a method of formation of metallic solids at around room temperature. This means the formation of solids under highly supercooled conditions. Amorphous and various metastable phases are formed by the plating method. In this paper, the mechanism of formation of metallic solid, and the formation of the amorphous and other metastable phases in various plated alloys, are discussed in relation to the thermal equilibrium diagram.

Optimization of hard magnetic properties by use of thermal equilibrium diagrams: B. Grieb et al (Magnetfabrik Schramberg GmbH, Germany), Powder Metallurgy, Vol 35, No 3, 1992, 221–227

Optimization of hard magnetic properties by use of thermal equilibrium diagrams: B. Grieb et al (Magnetfabrik Schramberg GmbH, Germany), Powder Metallurgy, Vol 35, No 3, 1992, 221–227

Etude par analyse en profondeur de l'interdiffusion en couches minces du couple AlCu: Cinetique de croissance des phases entre 200 et 300

This paper deals with thin layers interdiffusion of AlCu at annealing temperatures in the range of 200–300°C. The use of a method for depth analysis based upon the thermal ionization of sputtered material allows one to determine the composition of phases from the very beginning of their formation. Departure from stoichometry of about 1 % are measured for most observed phases. Comparison with thermal equilibrium diagram known at 600°C confirms the existence of the γ phase and shows that the γ 2 phase is in fact a mixture of two compounds Cu 32Al 19 and Cu 9Al 4. The main results to be mentioned are large diffusion coefficients (~ 10 −16cm 2/s at 220°C) and the formation of well defined compounds, with no appreciable composition range, growing in successive strates parallel to the plan of the interface of diffusion.

電析Ｎｉ‐Ｓｎ合金の微細構造と相に関する電子顕微鏡的研究

It has been reported that some of electrodeposited alloys are not identical with those represented in thermal equilibrium diagrams; for instance, in the electrodeposition of Ni-Sn alloy system, NiSn metastable phase is formed in a constituent of 40-60 at % of Sn. This study relates to Ni-Sn alloys electrodeposited from the pyrophosphate bath. By the microscopic examination (with T.E.M. and S.E.M.) and measurement of hardness, the following results were obtained on the microstructure and phase of the alloys. These alloys formed a supersaturated solid solution in a range of less than about 10 at % of Sn in Ni, formed a single phase of NiSn metastable phase in a range of about 40-56 at % of Sn, and formed two phases of Ni3Sn4 (δ1) and βSn (ε) in the range of more than about 56 at % of Sn. In the direct observation with T.E.M., the alloys, containing less than about 56 at % of Sn, formed nebulous crystals constituted by microcrystallites of about 50-100Å in size; on the contrary, the alloys containing Sn more than the former, were constituted by many large crystallites of about 300Å in size. The morphological observation of surface with S.E.M. showed that the alloys of less than about 10 at % of Sn had many microcracks, but the alloys of more Sn than that had no microcracks; and the alloys of about 40-56 at % of Sn were very smoothly electroplated. The Ni-Sn alloys forming metastable phases increased in hardness, which was Hv 550-750 at about 50 at % of Sn.