scholarly journals The Effect of Heat Treatment on the Microstructure and Phase Composition of Plasma Sprayed Al2O3 and Al2O3-TiO2 Coatings for Applications in Biomass Firing Plants

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1289
Author(s):  
Airingas Šuopys ◽  
Liutauras Marcinauskas ◽  
Viktorija Grigaitienė ◽  
Romualdas Kėželis ◽  
Mindaugas Aikas ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Steel Substrate ◽  
Atmospheric Pressure Plasma ◽  
X Ray Diffraction ◽  
Before And After ◽  
Al2o3 Phase ◽  
Tio2 Coatings ◽  
Plasma Sprayed ◽  
Steel Substrates

This study presents the thermal and chemical resistance of plasma-sprayed Al2O3 and Al2O3 doped with 13 wt.% of TiO2 coatings and their suitability for the fire grate of straw pellet furnaces. Coatings were deposited on steel substrates using direct current atmospheric pressure plasma spraying. The surface structure, elemental, and phase composition of formed coatings were analyzed before and after the thermal treatment, imitating natural application conditions. For the experiment, the annealing temperature was 500 °C for twenty-five cycles (80 min each). It was found that the steel substrate oxidized after five thermal cycles, and the formation of iron oxides was observed. The elemental composition of the Al2O3 and Al2O3-13 wt.% TiO2 coatings remained unchanged even after 25 cycles of heat treatment. The X-ray diffraction (XRD) results revealed that the alpha-Al2O3 to gamma-Al2O3 phase ratio in the Al2O3-TiO2 coating was reduced by only 8.7% after 25 cycles.

scholarly journals Influence of Heat Treatment on the Mechanical Properties of Ni Films on 430 Stainless Steel Substrate

2017 ◽  
Vol 36 (8) ◽  
pp. 855-861
Author(s):  
Yong Pan ◽  
Junwei Cui ◽  
Weixin Lei ◽  
Jie Zhou ◽  
Zengsheng Ma
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
X Ray Diffraction ◽  
Before And After ◽  
430 Stainless Steel ◽  
Different Temperatures ◽  
Texture Orientation

AbstractEffects of heat treatment on the mechanical properties of Ni films on 430 stainless steel substrate were investigated. The Ni films were annealed at heat treatment temperatures ranging from 0 °C to 800 °C for 2 h. The surface morphology, composition, and texture orientation of Ni films were studied by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The load–indentation depth curves of Ni films before and after heat treatment were measured by using nanoindentation method. In conjunction with finite element modeling and dimensional analysis, the stress–strain relationships of Ni films on 430 stainless steel substrate at different temperatures are successfully obtained by using a power-law hardening model.

Self-Healing Behavior of Pores in Atmosphere Plasma Sprayed Tritium Permeation Barrier Coatings

2010 ◽  
Author(s):  
Jifeng Gao ◽  
Jinping Suo ◽  
Dan Zhang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Self Healing ◽  
Martensitic Steels ◽  
X Ray Diffraction ◽  
Good Adhesion ◽  
X Ray ◽  
Before And After ◽  
Tritium Permeation ◽  
Plasma Sprayed

Decrease of pores in tritium permeation barriers is one of the most important problems to be addressed for the proper functioning of the fusion reactor. In this paper, a self-healing composite coating composed of TiC+mixture (TiC/Al2O3) +Al2O3 was developed to solve this problem. The coating was deposited on martensitic steels by plasma spraying with a thickness of 100μm. After heat-treatment, the morphology and phase of the coating were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the coating before and after heat treatment was examined by electrochemistry techniques. The results showed that the TiC+mixture (TiC/Al2O3)+Al2O3 coating exhibited good adhesion to the substrate and a perfect self-healing ability with the porosity decreased by 90% after heat-treatment. The corrosion resistance of the coating increased evidently after the heat treatment. The oxidation/expansion of TiC in the coating played an important role in the sealing of pores.

Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Elevated Temperatures ◽  
Initial Material ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

Investigation of Microstructure and Property of Fe3Al/Al2O3 Composites

2010 ◽  
Vol 150-151 ◽  
pp. 1409-1412 ◽  
Author(s):  
Tao Jiang
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Alloying ◽  
Sintering Process ◽  
Composite Powders ◽  
Al2o3 Composite ◽  
Al2o3 Phase ◽  
The Mean ◽  
Xrd Patterns ◽  
Al2o3 Matrix

The Fe3Al/Al2O3 composites were fabricated by pressureless sintering process. The Fe3Al intermetallics compounds powders were fabricated by mechanical alloying and heat treatment, then the Fe3Al powders and Al2O3 powders were mixed and the Fe3Al/Al2O3 composite powders were prepared, so the Fe3Al/Al2O3 composites were fabricated by sintering process at 1700oC for 2h. The phase composition and microstructure of Fe3Al intermetallics compounds powders produced by mechanical alloying and heat treatment were investigated. The phase composition, microstructure and mechanical properties of the Fe3Al/Al2O3 composites sintered bulks were investigated. The XRD patterns results showed that there existed Fe3Al phase and Al2O3 phase in the sintered composites. The Fe3Al/Al2O3 composites sintered bulks exhibited the homogenous and compact microstructure, the Fe3Al particles were homogenously distributed in the Al2O3 matrix, the mean particles size of Fe3Al intermetallics was about 3-5μm. The Fe3Al/Al2O3 composites exhibited more homogenous and compact microstructure with the increase of Fe3Al content in the Al2O3 matrix. The density and relative density of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content. The fracture strength and fracture toughness of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content. The elastic modulus and hardness (HRA) of the Fe3Al/Al2O3 composites decreased gradually with the increase of Fe3Al content.

scholarly journals An Investigation of the Electrical Behavior of Thermally Sprayed Aluminum Oxide

1996 ◽  
Author(s):  
C.J. Swindeman ◽  
R.D. Seals ◽  
W.P. Murray ◽  
M.H. Cooper ◽  
R.L. White
Keyword(s):  
Electrical Properties ◽  
Aluminum Oxide ◽  
Dielectric Constants ◽  
Electrical Behavior ◽  
X Ray Diffraction ◽  
Heating And Cooling ◽  
Thermally Sprayed Aluminum ◽  
Plasma Sprayed ◽  
And Control ◽  
Steel Substrates

Abstract Electrical properties of plasma-sprayed aluminum oxide coatings were measured at temperatures up to 600 °C. High purity (>99.5 wt% pure Al2O3) alumina powders were plasma-sprayed on stainless steel substrates over a range of power levels, using two gun configurations designed to attain different spray velocities. Key electrical properties were measured to evaluate the resultant coatings as potential insulating materials for electrostatic chucks (ESCs) being developed for semiconductor manufacturing. Electrical resistivity of all coatings was measured under vacuum upon heating and cooling over a temperature range of 20 to 600 °C. Dielectric constants were also measured under the same test conditions. X-ray diffraction was performed to examine phase formation in the coatings. Results show the importance of powder composition and careful selection and control of spray conditions for optimizing electrical behavior in plasma-sprayed aluminum oxide, and point to the need for further studies to characterize the relationship between high temperature electrical properties, measured plasma-spray variables, and specific microstructural and compositional coating features.

Comparative Evaluation of the Bioactive Behavior of HA and ZrO2 Reinforced Coatings

2011 ◽  
Vol 493-494 ◽  
pp. 447-452
Author(s):  
George Theodorou ◽  
Ourania Menti Goudouri ◽  
Lambrini Papadopoulou ◽  
Nikolaos Kantiranis ◽  
Subramaniam Yugeswaran ◽  
...  
Keyword(s):  
Steel Substrate ◽  
In Vitro Bioactivity ◽  
Biological Fixation ◽  
Metal Implants ◽  
Ha Coating ◽  
Biological Responses ◽  
Before And After ◽  
Sbf Solution ◽  
Plasma Sprayed

The clinical use of plasma-sprayed hydroxyapatite (HA) coatings on metal implants has been widely investigated as the HA coating can achieve the firm and direct biological fixation with the surrounding bone tissue. It is shown in previous studies that the mechanical properties of HA coatings are improved by the addition of ZrO2 particles during the deposition of the coating on the substrate. Subsequently, the cohesive and adhesive strengths of plasma-sprayed hydroxyapatite (HA) coatings were strengthened by the ZrO2 particles addition as a reinforcing agent in the HA coating (HA+ZrO2 composite coating). The aim of the present work is to investigate and evaluate the in vitro bioactivity assessment of HA and HA/ZrO2 coatings, on stainless steel substrate, soaked in c-SBF, in order to study and compare their biological responses. The coatings were produced using vapor plasma spraying (VPS). The characterization of the surface of the coatings before and after soaking in SBF solution was performed using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction analysis (XRD). All samples were smoothed before insertion in the medium and the in vitro bioactivity of all coating samples was tested in conventional Simulated Body Fluid (c-SBF) solution for various immersion times.

scholarly journals Microstructure Evolution and Performance Improvement of Hypereutectic Al–Mg2Si Metallic Composite with Ca or Sb

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2714
Author(s):  
Min Zuo ◽  
Boda Ren ◽  
Zihan Xia ◽  
Wenwen Ma ◽  
Yidan Lv ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nucleation Behavior ◽  
X Ray ◽  
Primary Mg2si ◽  
Before And After ◽  
And Performance ◽  
Hardness Values

In this article, the modification effects on Al–Mg2Si before and after heat treatment were investigated with Ca, Sb, and (Ca + Sb). In comparison with single Ca or Sb, the samples with composition modifiers (Ca + Sb) had the optimal microstructure. The sample with a molar ratio for Ca-to-Sb of 1:1 obtained relatively higher properties, for which the Brinell hardness values before and after heat treatment were remarkably increased by 31.74% and 28.93% in comparison with bare alloy. According to differential scanning calorimetry analysis (DSC), it was found that the nucleation behavior of the primary Mg2Si phase could be significantly improved by using chemical modifiers. Some white particles were found to be embedded in the center of Mg2Si phases, which were deduced to be Ca5Sb3 through X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM) analyses. Furthermore, Ca5Sb3 articles possess a rather low mismatch degree with Mg2Si particles based on Phase Transformation Crystallography Lab software (PTCLab) calculation, meaning that the efficient nucleation capability of Ca5Sb3 for Mg2Si particles could be estimated.

X-Ray Diffraction Studies on the Titanium-Nickel System

1962 ◽  
Vol 6 ◽  
pp. 74-84
Author(s):  
John V. Gilfrich
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Stoichiometric Composition ◽  
Physical Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Property Data ◽  
Before And After ◽  
Titanium Nickel ◽  
Physical Property Data

AbstractX-ray diffraction studies were made on the Ti–Ni system around the stoichiometric composition of the intermetallic compound TiNi to clarify some confusion which has existed about the phase diagram in this region, and to explain some anomalies in the physical properties of this material. Wrought and cast samples were examined at room temperature both before and after heat treatment and at temperatures both above and below ambient. The compound TiNi does exist at room temperature. The phase purity of the particular sample was found to be greatly affected by such factors as minor variations in composition, heat treatment, and method of sample preparation. Some confirming metallographlc and physical property data will also be presented.

Characterization and Photocatalytic Properties of Plasma Sprayed TiO2 Coatings Deposited from Nanoparticles

2006 ◽  
Vol 317-318 ◽  
pp. 561-564
Author(s):  
Huang Chen ◽  
Tae Ho Kim ◽  
Soo Wohn Lee ◽  
Ho Sung Aum ◽  
Bo Young Hur ◽  
...  
Keyword(s):  
Photocatalytic Property ◽  
Photocatalytic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Tio2 Coatings ◽  
Plasma Sprayed ◽  
Tem Transmission Electron Microscopy ◽  
Scanning Electron ◽  
Observation Results

The phase and microstructure of four kinds of plasma sprayed TiO2 coatings (P25, ST, NK, KT) were characterized by XRD (X-ray Diffraction), FE-SEM (Field Emission Scanning Electron Microscope) and TEM ( Transmission Electron Microscopy). Their photocatalytic properties were discussed in relation to phase composition and microstructure. The FE-SEM observation results reveal that there are quite a number of nanoparticles on the surfaces of all four kinds of plasma sprayed TiO2 coatings, which provide photocatalytic reactive sites. Based on the observation results of FE-SEM and TEM, the microstructure schematic of plasma sprayed TiO2 coatings using nanoparticles as feedstock is suggested. The best photocatalytic property of P25 coating among the four plasma sprayed TiO2 coatings is attributed to the combination of its fine “cauliflower” structure and the highest anatase content.

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