Research on Thermal Spray Al-Al2O3/TiO2 Coating and Diffusion Treatment on Magnesium Alloy

2006 ◽  
Vol 532-533 ◽  
pp. 217-220
Author(s):  
Hong Ye ◽  
Zhong Lin Yan ◽  
Zhi Fu Sun ◽  
Ying Wang
Keyword(s):  
Magnesium Alloy ◽  
Thermal Shock ◽  
High Hardness ◽  
Flame Spray ◽  
Diffusion Treatment ◽  
Az91d Magnesium Alloy ◽  
Spray Method ◽  
Shock Resistance ◽  
And Diffusion ◽  
Electronic Microscope

Flame spray method was used to prepare the Al-Al2O3/TiO2 gradient coating on AZ91D magnesium alloy surface, where diffusion treatment for 2 hours at 380～420 °C was needed to reinforce the binding strength between the coating and the substrate. Appearance and compositions of the coating were analyzed by scanning electronic microscope (SEM) and electron probe microanalysis (EPMA), and the thermal shock resistance and wear resistance of the coating were tested. The result shows: Al-Mg diffusion is produced between the coating and the substrate, for good metallurgy; coating acquires high hardness and resistant to wear and thermal shock.

Effect of Heat Treatment on Microstructures and Properties of Zinc-Aluminum Coating on AZ91D Magnesium Alloy

2008 ◽  
Vol 373-374 ◽  
pp. 55-58 ◽  
Author(s):  
Jin Zhang ◽  
Ying Wang
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Thermal Shock ◽  
Spray Coating ◽  
Aluminum Coating ◽  
Post Heat Treatment ◽  
Corrosion Resistant ◽  
Az91d Magnesium Alloy ◽  
Corrosion Behaviors ◽  
Shock Resistance

A protective zinc-aluminum spray coating and a post heat treatment was carried out onto AZ91D magnesium alloy. The effect of post heat treatment on the interfacial characteristics, corrosion behaviors, micro-hardness, and thermal shock resistance of the zinc-aluminum coating were evaluated in this paper. It was found that a dense inter-coating formed at the Zn/Mg substrate interface followed by the post heat treatment. The results of EDS analysis indicated that the diffusion took place among Mg, Al and Zn atoms. The Zn-Al deposited coating with heat treatment had much more corrosion resistant and higher resistant to thermal shock. It was harder than as-received AZ91D Mg alloy.

Properties of Ceramic Coatings on the Wall of Coke Oven

2011 ◽  
Vol 189-193 ◽  
pp. 1105-1108
Author(s):  
Shu Xian Liu ◽  
Li Li Shen ◽  
Qian Ping Wang
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
High Hardness ◽  
Coke Oven ◽  
Ceramic Coatings ◽  
Good Adhesion ◽  
Before And After ◽  
Shock Resistance ◽  
Uncoated Specimen ◽  
Better Than

Flame sprayed ceramic coatings on the wall of coke oven are characterized before and after melting. The attempt has been made to investigate thermal shock resistant, carbon deposit resistant, wear resistant of the coated and melted samples. The techniques used are SEM and XRD. The results show that: 1) Presence of quartz, corundum and mullite are identified in the surface of the coated specimen. Good adhesion between the coating and the substrate is caused by presence of quartz which is the same content as the substrate.2) The thermal shock resistance cycles of the coating samples are 15 ~ 30 times, but uncoated samples are only 1~2 times. The main reason is that he coating–substrate interface shows no gaps or cracks, and it has a characteristic feature of good adhesion between the coating and the substrate. 3) The wear resistance of the coated samples are better than that of the uncoated samples because glass-coating is more smooth than the uncoated specimen and the mullite and corundum in the coating have the high hardness value that makes the hardness of the coating increased.

The Influence of Particles Size and Composition Variation of NiCr-CrC(20NiCr) Metal Matrix Composites Coatings Properties on Boiler Tubes Application

2017 ◽  
Vol 889 ◽  
pp. 30-35 ◽  
Author(s):  
Erie Martides ◽  
Budi Prawara ◽  
Husaini Ardy ◽  
Endro Junianto ◽  
Budi Priyono
Keyword(s):  
Particle Size ◽  
Thermal Shock ◽  
Metal Matrix ◽  
Thermal Shock Resistance ◽  
Resistance Testing ◽  
Matrix Composites ◽  
Spray Method ◽  
Hvof Thermal Spray ◽  
Boiler Tubes ◽  
Shock Resistance

Deposition of NiCr-CrC(20NiCr) metal matrix composite (MMCs) coating have been applied on the substrate of boiler tubes material with High Velocity Oxygen Fuel (HVOF) thermal spray method and constant parameter. Variation of particle size and composition on MMCs was conducted to determined the optimum conditions for boiler applications. Microvickers hardness, metallography and thermal shock resistance testing were investigated. The best performance for boiler tubes application is MMC NiCr-CrC(20NiCr) with 270 mesh of NiCr particles size and 60:40 of composition as evidence by the highest of hardness value (410 Hv) and slightly of discoloration after thermal shock resistance with two variation cooling medium. While at MMC NiCr-CrC(20NiCr) with 70:30 variation composition, coating hardness value will decrease in line with the smaller of particle size of NiCr.

Microstructure and Mechanical Properties of (TiAlNb)N Films

2014 ◽  
Vol 915-916 ◽  
pp. 812-815 ◽  
Author(s):  
Li Yan Yin ◽  
Jun Zhang
Keyword(s):  
Mechanical Properties ◽  
Thermal Shock ◽  
Bias Voltage ◽  
Thermal Shock Resistance ◽  
High Speed ◽  
High Speed Steel ◽  
Fracture Morphology ◽  
X Ray Diffraction ◽  
Shock Resistance ◽  
Electronic Microscope

(TiAlNb)N hard reactive films are prepared by multi-arc ion plating technology using the combination of Ti-50Al (at%) and Ti-25Nb (at%) alloy targets. The high speed steel (HSS) is adopted as substrate. The surface and cross-fracture morphology, the surface compositions and the phase structures of the as-deposited (TiAlNb)N films are observed and measured by scan electronic microscope (SEM) and X-ray diffraction (XRD). The mechanical properties including the micro-hardness, the adhesion between film and substrate, the thermal shock resistance of the as-deposited (TiAlNb)N films are systemically investigated. The effects of deposition bias voltage and the addition of Nb element on the as-deposited (TiAlNb)N films are discussed. The optimally comprehensive performances, especially hardness and thermal shock resistance, exhibited by (TiAlNb)N films with bias voltage of 100V.

Electron Beam Surface Alloying of a Magnesium Alloy with Al

2008 ◽  
Vol 373-374 ◽  
pp. 326-329
Author(s):  
Hong Ye ◽  
Zhong Lin Yan
Keyword(s):  
Solid Solution ◽  
Electron Beam ◽  
Magnesium Alloy ◽  
Intermetallic Phase ◽  
Anticorrosion Property ◽  
Flame Spray ◽  
Alloy Az91d ◽  
Spray Method ◽  
Melted Layer ◽  
Beam Surface

Magnesium alloy is an important engineering materials，but the wider application is restricted by poor corrosion and wear resistance. In the present study, an attempt was made to enhance corrosion resistance and microhardness of Mg alloy AZ91D by electron beam alloying. Flame spray method was used to prepare Al coating on the surface of AZ91D magnesium alloy, then remelted by high power electron beam. The microstructure and composition of the coating were analyzed in detail. Al-Mg diffusion was produced between the coating and the substrate to lead to the re-distribution of alloy elements in the melted layer. The coating was mainly composed of Al-Mg solid solution, Mg-Al intermetallic compounds and Mg-Al solid solution transition zone. Microhardness of the alloying layer was enhanced to 220 HV0.05 as compared to 70-80 HV0.05 of the substrate, due to the intermetallic phase formation, such as Mg2Al3 and Mg17Al12. These phases were good to improve anticorrosion property of AZ91D alloy．

The Heat and Diffusion Treatment of Natural and Synthetic Sapphires

1981 ◽  
Vol 17 (8) ◽  
pp. 528-541 ◽  
Author(s):  
Robert Crowningshield ◽  
Kurt Nassau
Keyword(s):  
Diffusion Treatment ◽  
And Diffusion ◽  
Natural And Synthetic
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