Study on the High-Temperature Coating in Preventing Oxidation and Decarburization

2010 ◽  
Vol 154-155 ◽  
pp. 1830-1833
Author(s):  
Sheng Yao Lin ◽  
Lu Wen Tang ◽  
Jian Min Zeng
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Raw Materials ◽  
Low Cost ◽  
Environment Friendly ◽  
Temperature Oxidation ◽  
Workpiece Surface ◽  
Processing Properties ◽  
The Impact ◽  
Oxidation Loss

In order to reduce the oxidation and decarburization caused by high temperature in the course of the heat treatment of metal materials, an environment-friendly coating consisting of glass powder and red mud as the main raw materials is applied. It is brushed on the workpiece surface, heated in the box-type resistance furnace.The high temperature oxidation weight gain and the depth of decarburization between naked steel and coating steel are studied using weight gain method and metallographic method. The impact of the coating to reduce oxidation loss and the main properties of coating are analyzed. The result shows that processing properties of the glass-based coating are excellent:it has no crack at high temperature, distributes uniformly on the workpiece surface and can be self-spalling after quenching. It effectively prevents the workpiece from oxidation and decarburization at 800-1100 . The coating is of low cost and easy to use.

scholarly journals Impact of Sodium Hexametaphosphate on the Flotation of Ultrafine Magnesite from Dolomite-Rich Desliming Tailings

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 499
Author(s):  
Duong Huu Hoang ◽  
Doreen Ebert ◽  
Robert Möckel ◽  
Martin Rudolph
Keyword(s):  
Ultrafine Particles ◽  
Raw Materials ◽  
Low Cost ◽  
Froth Flotation ◽  
Open Circuit ◽  
Ore Deposits ◽  
Sodium Hexametaphosphate ◽  
Low Grade ◽  
Low Contrast ◽  
The Impact

The depletion of ore deposits, the increasing demand for raw materials, the need to process low-grade, complex and finely disseminated ores, and the reprocessing of tailings are challenges especially for froth flotation separation technologies. Even though they are capable of handling relatively fine grain sizes, the flotation separation of very fine and ultrafine particles faces many problems still. Further, the flotation of low-contrast semi-soluble salt-type minerals with very similar surface properties, many complex interactions between minerals, reagents and dissolved species often result in poor selectivity. This study investigates the flotation beneficiation of ultrafine magnesite rich in dolomite from desliming, currently reported to the tailings. The paper especially focuses on the impact of the depressant sodium hexametaphosphate (SHMP) on the following: (i) the froth properties using dynamic froth analysis (DFA), (ii) the separation between magnesite and dolomite/calcite, and (iii) its effect on the entrainment. As a depressant/dispersant, SHMP has a beneficial impact on the flotation separation between magnesite and dolomite. However, there is a trade-off between grade and recovery, and as well as the dewatering process which needs to be considered. When the SHMP increases from 200 g/t to 700 g/t, the magnesite grade increases from 67% to 77%, while recovery decreases massively, from 80% to 40%. The open circuit with four cleaning stages obtained a concentrate assaying 77.5% magnesite at a recovery of 45.5%. The dolomite content in the concentrate is about 20%, where 80% of dolomite was removed and importantly 98% of the quartz was removed, with only 0.3% of the quartz in the final concentrate. Furthermore, the application of 1-hydroxyethylene-1,1-diphosphonic acid (HEDP) as a more environmentally friendly and low-cost alternative to SHMP is presented and discussed. Using only 350 g/t of HEDP can achieve a similar grade (76.3%), like 700 g/t of SHMP (76.9%), while obtaining a 17% higher magnesite recovery as compared to 700 g/t of SHMP. Interestingly, the proportion of hydrophilic quartz minerals ending up in the concentrate is lower for HEDP, with only 1.9% quartz at a recovery of 21.5% compared to the 2.7% of quartz at a recovery of 24.9% when using SHMP. The paper contributes in general to understanding the complexity of the depressant responses in froth flotation.

Impact of Carrier Lifetime Enhancement Using High Temperature Oxidation on 15 kV 4H-SiC P-GTO Thyristor

2017 ◽  
Vol 897 ◽  
pp. 587-590 ◽  
Author(s):  
Sei Hyung Ryu ◽  
Daniel J. Lichtenwalner ◽  
Edward van Brunt ◽  
Craig Capell ◽  
Michael J. O’Loughlin ◽  
...  
Keyword(s):  
High Temperature ◽  
Carrier Lifetime ◽  
Voltage Drop ◽  
Current Gain ◽  
Slight Reduction ◽  
Temperature Oxidation ◽  
Forward Voltage Drop ◽  
P Type ◽  
The Impact ◽  
Lifetime Enhancement

The impact of the lifetime enhancement process using high temperature thermal oxidation method on 4H-SiC P-GTOs was investigated. 15 kV 4H-SiC P-GTOs with 140 μm thick drift layers, with and without 1450°C lifetime enhancement oxidation (LEO) process, were compared. The LEO process increased the average carrier lifetime in p-type epi layer from 0.9 μs to 6.25 μs, and it was observed that the effectiveness of the lifetime enhancement process was very sensitive to the doping concentration. The device with the LEO process showed a significant reduction in forward voltage drop and a substantially lower holding current, as expected from the carrier lifetime measurements. However, a slight reduction in blocking capability was also observed from the devices treated with LEO process. The common emitter current gain (β) of the wide base test NPN BJT was approximately 10X higher for the wafer with LEO process.

Performance of Fe-33Ni-18Cr Alloy at High Temperature Oxidation

2020 ◽  
Vol 1010 ◽  
pp. 65-70
Author(s):  
Zahraa Zulnuraini ◽  
Noraziana Parimin
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxide Scale ◽  
High Temperature Oxidation ◽  
Thick Layer ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
Oxide Particles ◽  
Lower Temperature

This paper investigates the performance of Fe-33Ni-18Cr alloy at high temperature oxidation. The samples were isothermally oxidized at three different oxidation temperatures, namely, 600 °C, 800 °C and 1000 °C for 150 hours. This alloy was ground by using several grits of SiC paper as well as weighed by using analytical balance and measured by using Vernier caliper before oxidation test. The characterization was carried out using scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) and x-ray diffraction (XRD). The results show that, the higher oxidation temperatures, the weight gain of the samples were increase. Sample of 1000 °C indicate more weight gain compared to samples oxidized at 600 °C and 800 °C. The kinetic of oxidation of all samples followed the parabolic rate law. The surface morphology of oxide scale at lower temperature is thin and form a continuous layer, while at high temperature, the oxide scale develops thick layer with angular oxide particles.

EFFECT OF La2O3 ON HIGH-TEMPERATURE OXIDATION RESISTANCE OF ELECTROSPARK DEPOSITED Ni-BASED COATINGS

2014 ◽  
Vol 21 (05) ◽  
pp. 1450071 ◽  
Author(s):  
YUXIN GAO ◽  
JIAN YI ◽  
ZHIGANG FANG ◽  
HU CHENG
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Kinetic ◽  
High Temperature Creep ◽  
Chromia Scale ◽  
Temperature Oxidation ◽  
Phase Structures ◽  
Short Time

The oxidation tests of electrospark deposited Ni -based coatings without and with 2.5 wt.% La 2 O 3 were conducted at 960°C in air for 100 h. The oxidation kinetic of the coatings was studied by testing the weight gain. The phase structures and morphologies of the oxidized coatings were investigated by XRD and SEM. The experimental results show that the coatings with 2.5 wt.% La 2 O 3 exhibits excellent high-temperature oxidation resistance including low oxidation rate and improved spallation resistance, due to the formation of a denser and more adherent oxide scale compared with that without La 2 O 3. The effects of La 2 O 3 on the oxidation resistance include the following two aspects: First, refinement of the coating grains promotes the selective oxidation of Cr , leading to the formation of protective chromia scale in a short time, and second, refinement of the oxide grains enhances the high-temperature creep rate, resulting in decrease of inner stress and improvement of spallation resistance of the oxide layer.

scholarly journals STUDY ON THE GRINDING TIME DURATION IMPACT ON THE PROPERTIES OF PAPER FROM ALTERNATIVE RAW MATERIALS

2020 ◽  
Vol 2020 (3) ◽  
pp. 24-31
Author(s):  
Z Galimova ◽  
◽  
H Babakhanova ◽  
M Abdunazarov ◽  
I Ismoilov ◽  
...  
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Milling Process ◽  
Raw Material ◽  
Time Duration ◽  
Paper Production ◽  
Fiber Materials ◽  
The Impact

Both raw and recycled fiber materials are used for paper production. The increase in percentage use of the latter is due to their paper-forming properties, availability and low cost. The article explores the possibility of using pulp from the inner layer of mulberry twig bark. Mulberry twigs, after removing leaves, which are the main raw material in silk production, have no practical industrial application. Recycling waste - mulberry branches - for the production of pulp is therefore relevant as it is aimed at solving raw material and environmental problems. The purpose of this work is to use local raw materials for paper production, study the impact of processing method of the grinding process on paper forming properties. During grinding the mechanical processes of changes of fibers determine mainly structure of a paper sheet, and colloidal-physical processes - bind and ability of fibers to form strong, homogenous and smooth structure of paper. The structure of the sheet of paper facilitates excessive or "selective" ink absorption into the pores of the paper and thus predetermines the quality of reproduction during the printing process. Methods for determining the physical and mechanical properties of papers were used in this work, and changes in the surface structure of samples cast at various technological modes of the milling process were studied. The results of the study revealed that the addition of cellulose mass from the inner layer of mulberry twig bark helps to obtain a strong paper. The optical properties of the paper, which contains cotton and cellulose from the inner layer of mulberry branch bark, are explained by the whiteness of the added fibers themselves. The strength properties of the paper at a weight grinding degree of 300 CWR are explained by the bond between the split and strongly interwoven fibers of the cellulose fibers. It has been established that the addition of more than 30% cellulose from the inner layer of the mulberry branch bark to the paper pulp mass is undesirable, as this adversely affects the whiteness of the paper

scholarly journals An Experimental Study for the Remediation of Industrial Waste Water Using a Combination of Low Cost Mineral Raw Materials

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 207 ◽  
Author(s):  
Petros Petrounias ◽  
Aikaterini Rogkala ◽  
Panagiota Giannakopoulou ◽  
Basilios Tsikouras ◽  
Paraskevi Lampropoulou ◽  
...  
Keyword(s):  
Waste Water ◽  
Continuous Flow ◽  
Mine Drainage ◽  
Raw Materials ◽  
Low Cost ◽  
Raw Material ◽  
Experimental Device ◽  
Mineral Raw Materials ◽  
Research Gap ◽  
The Impact

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials, as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this study, in order to examine the remediation, in lab scale, of the drainage waste water of Agios Philippos mine, an experimental electrically continuous flow-driven forced device was constructed, enriching the research gap relative to this type of remediation approach. Through this experimental device, the use of certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat, and biochar) was studied. Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the new 7-day experimental electrically continuous flow-driven forced device with certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 was achieved. Moreover, with use of the experimental device, the removal of toxic load was achieved, and more specifically the concentration of Fe was decreased from 6149 to 1300 ppb, Cu from 8847 to 35 ppb, and Zn from 285,458 to 50,000 ppb.

The Exploring Research of the Determination Method of Magnesium Oxide Hydration

2010 ◽  
Vol 177 ◽  
pp. 342-345 ◽  
Author(s):  
Zhan Peng Zhang ◽  
Cheng Zhang ◽  
De Xing Huang ◽  
Dan Yu Jiang ◽  
Rong Juan Zhang ◽  
...  
Keyword(s):  
Magnesium Oxide ◽  
Refractory Industry ◽  
Raw Materials ◽  
Low Cost ◽  
Solid Content ◽  
Hydration Reaction ◽  
Determination Method ◽  
Volumetric Expansion ◽  
The Impact ◽  
Kinetics Of

Magnesium oxide is one of the most important raw materials in the refractory industry due to its high melting point (2800oC), corrosion resistance in the basic environment, and low cost. Nevertheless, magnesium oxide reacts easily with water to produce magnesium hydrate, which is followed by a large volumetric expansion, limiting its application in refractory industry. As the hydration of MgO is very important either in theory or in industrial production of magnesium, in this paper, the influence of temperature, residence time, as well as the impact of the solid content on MgO hydration and the kinetics of hydration reaction was evaluated to optimize the determination method of magnesium oxide hydration in refractory industry.

High Temperature Oxidation of Chromium-Nickel Steels★

CORROSION ◽  
1959 ◽  
Vol 15 (3) ◽  
pp. 57-62 ◽  
Author(s):  
D. CAPLAN ◽  
M. COHEN
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Stainless Steels ◽  
High Temperature Oxidation ◽  
Surface Preparation ◽  
Austenitic Stainless Steels ◽  
Chromium Steel ◽  
Temperature Oxidation ◽  
Thin Oxide Film ◽  
Scale Layer

Abstract The scaling of austenitic stainless steels Type 302, 309 and 330 has been investigated by weight gain vs time measurements in air at 1600 to 2000 F and subsequent examination of the scales. As had been found previously with chromium steel, the curves exhibit breaks indicating intermediate periods of rapid oxidation due to disruption of the protective scale layer. Accumulation of silica at the metal/scale interface is found to contribute to this disruption; voids are considered to have the same effect. A distinction is drawn between such breaks and the type which arises from the extraordinary protectiveness of an initial thin oxide film, which is markedly affected by surface preparation and prior treatment. 3.2.3

scholarly journals An Experimental Study for the Remediation of Industrial Waste Water Using Combination of Low Cost Mineral Raw Materials

2019 ◽  
Author(s):  
Petros Petrounias ◽  
Aikaterini Rogkala ◽  
Panagiota P. Giannakopoulou ◽  
Basilios Tsikouras ◽  
Paraskevi Lampropoulou ◽  
...  
Keyword(s):  
Waste Water ◽  
Continuous Flow ◽  
Mine Drainage ◽  
Raw Materials ◽  
Low Cost ◽  
Raw Material ◽  
Industrial Waste Water ◽  
Mineral Raw Materials ◽  
Ph Values ◽  
The Impact

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this way, the value of mineral raw materials can be prolonged for as long as possible, waste generation and exploitation of natural resources are minimized and resources are kept as far as possible within the existing economy. In this study, an electrically continuous flow driven forced device proposed and demonstrated for the remediation of waste water in lab-scale by using certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat and biochar). Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the proposed 7-day experimental electrically continuous flow driven forced device with the certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 as well as significant removal of Fe, Cu and Zn was achieved.

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