PREPARATION OF MICROARC OXIDATION COATINGS ON 6061 ALUMINUM ALLOYS AND THEIR THERMAL SHOCK RESISTANCE

2009 ◽  
Vol 16 (03) ◽  
pp. 393-399 ◽  
Author(s):  
WENBIN XUE ◽  
YING ZHANG ◽  
XINGLI JIANG ◽  
ZHUO YANG
Keyword(s):  
Aluminum Alloys ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Microarc Oxidation ◽  
Alloy Coating ◽  
Ceramic Coatings ◽  
Phase Constituent ◽  
Thick Coating ◽  
Coated Alloy ◽  
Shock Resistance

The thick ceramic coatings were prepared on 6061 aluminum alloys by microarc oxidation in a silicate electrolyte. The morphology and phase constituent of the coatings with different thickness were studied by scanning electron microscope, and X-ray diffraction. Scratch and thermal shock tests were employed to evaluate the adhesion between the coating and alloy substrate. The maximum microhardness and its position away from alloy/coating interface increases with increasing the coating thickness. The critical scratch force for the coating break was about 55 N in the 50 μm thick coating. Thermal shock resistance of the coatings depend on their thickness and thinner coating has better thermal shock resistance. The coated alloy with 50 μm thick coating can be subjected to 50 times thermal cycles of heating up to 500°C followed by quenching into water.

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.

Study on Thermal Shock Resistance of Nano-CeO2–Y2O3 Co-Stabilized ZrO2 (CYSZ) Ceramic Powders Thermal Barrier Coating of Aircraft Engine

2019 ◽  
Vol 14 (11) ◽  
pp. 1597-1605
Author(s):  
Yang Lyu ◽  
Xuan Shao ◽  
Wen-Xue Wang ◽  
Hui Tang
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coating ◽  
Thermal Shock Resistance ◽  
Ceramic Coatings ◽  
Precipitation Method ◽  
Thermal Barrier ◽  
Ceramic Powders ◽  
Alloy Matrix ◽  
Barrier Coating ◽  
Shock Resistance

In this paper, nano-CeO2–Y2O3 co-stabilized ZrO2 ceramic powders (CYSZ) were firstly prepared by co-precipitation method, and CYSZ powder was spray-granulated, followed by thermal plasma spraying of nano-CYSZ thermal barrier coating on 35Cr2Ni4 MoA alloy matrix. After XRD and SEM analysis, the five CYSZ ceramic coatings (CeO2 content 0, 1, 5, 10, 15 mol%) prepared were tetragonal phase structures before and after the thermal shock experiment, and the thickness of CYSZ ceramic coating was about 200 μm. Adding appropriate amount of nano CeO2 promoted the formation of micro-cracks in the coating, released the coating stress, slowed down the thermal shock damage process, and prevented the transformation from t-ZrO2 to m-ZrO2. The AFM morphology showed that the coating surface grains grow vertically after thermal shock cycle, which indicated that the entry of Ce4+ into ZrO2 lattice resulted in lattice distortion and made the grains more stable. When the content of CeO2 is 1 mol%, the thermal shock resistance excellent is 84 times. Therefore, the addition of CeO2 can effectively improve the thermal shock resistance performance of CYSZ thermal barrier coating, meeting the requirements of high temperature working conditions of aeroengine and hot-end components.

Fabrication of Self-Healing Ceramic Coatings Against Oxidation for Carbon/Carbon Composites Using Polysilazane and B4C Filler

2010 ◽  
Vol 434-435 ◽  
pp. 455-458 ◽  
Author(s):  
Chun Ying Tian ◽  
Hong Li Liu
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Loss Rate ◽  
Ceramic Coatings ◽  
Carbon Composites ◽  
Self Healing ◽  
Weight Loss Rate ◽  
Shock Resistance ◽  
Polymer Pyrolysis ◽  
B4c Powder

The self-healing ceramic coating against oxidation for carbon/carbon composites was fabricated via preceramic polymer pyrolysis process using polysilazane as preceramic and B4C powder as filler. By means of SEM and XRD, the phase composition and the microstructure of coatings were characterized, and preliminarily study on its anti-oxidation ability and thermal shock resistance was conducted. The results showed that the parameters including content of B4C, coating thickness, number of times of coating/pyrolysis play an important role on anti-oxidation ability of coatings. The optimal anti-oxidation ability was obtained when the content of B4C reached 50wt%, the number of times of coating/pyrolysis reached three and 1200°C was chosen as pyrolysis temperature. The thermal shock resistance test was conducted 50 times and the weight loss rate was 7.14% at 1000°C, which proved that the thermal shock resistance was excellent.

Thermal-shock resistance of glass-ceramic coatings

1984 ◽  
Vol 41 (7) ◽  
pp. 293-296
Author(s):  
G. I. Zhuravlev ◽  
L. V. Rudenko ◽  
G. A. Kudryavtseva ◽  
L. I. Venzel'
Keyword(s):  
Thermal Shock ◽  
Glass Ceramic ◽  
Thermal Shock Resistance ◽  
Ceramic Coatings ◽  
Shock Resistance ◽  
Glass Ceramic Coatings
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