scholarly journals Microstructure and Properties of Atmospheric Plasma Sprayed (Al,Cr)2O3–TiO2 Coatings from Blends

Author(s):  
Maximilian Grimm ◽  
Susan Conze ◽  
Lutz-Michael Berger ◽  
Rico Drehmann ◽  
Thomas Lampke

AbstractCoatings prepared from chromia-rich (Al,Cr)2O3 solid solution (ss) feedstock powders are intended to improve the properties of Cr2O3 coatings, but are rarely studied so far. In this work, the processability of a commercial (Al,Cr)2O3 solid solution (ss) powder containing 78 wt.% Cr2O3 by atmospheric plasma spraying (APS), the corresponding coating microstructures and properties were investigated. Possible further improvements were expected by blending with 2, 23 and 54 wt.% TiOx powder. For comparison, plain Cr2O3 and TiOx coatings were studied as well. The microstructures were analyzed using SEM, EDS and XRD measurements. Hardness (HV0.3) was measured, as well as the dry unidirectional sliding wear resistance and the abrasion wear resistance (ASTM G65). Moreover, the corrosion and electrical insulating properties were measured. The (Al,Cr)2O3 ss showed only a small change of the composition, and the formation of γ-Al2O3, as found for alumina-rich (Al,Cr)2O3 ss powders, was avoided. Compared to the plain chromia coating, some improvements of the processability and coating properties for the ss (Al,Cr)2O3 coating were found. The most balanced coating performance was achieved by blending the ss (Al,Cr)2O3 with 2 wt.% TiOx, as this coating showed both a high sliding and abrasion wear resistance, in combination with a high corrosion resistance.

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 42 ◽  
Author(s):  
Maximilian Grimm ◽  
Susan Conze ◽  
Lutz-Michael Berger ◽  
Gerd Paczkowski ◽  
Thomas Lindner ◽  
...  

Al2O3, Cr2O3, and TiO2 are most commonly used oxide materials for thermal spray coating solutions. Each oxide shows unique properties comprising behavior in the spray process, hardness, corrosion, and wear resistance. In order to exploit the different advantages, binary compositions are often used, while ternary compositions are not studied yet. Atmospheric plasma spraying (APS) of ternary compositions in the Al2O3-Cr2O3-TiO2 system was studied using blends of plain powders with different ratios and identical spray parameters. Coatings from the plain oxides were studied for comparison. For these powder blends, different deposition rates were observed. The microstructure, roughness, porosity, hardness, and wear resistance were investigated. The formation of the splats from particles of each oxide occurs separately, without interaction between the particles. The exception are the chromium oxide splats, which contained some amounts of titanium. The predominant oxide present in each blend has a decisive influence on the properties of the coatings. While TiOx causes a low coating porosity, the wear resistance can be increased by adding Cr2O3.


2005 ◽  
Vol 20 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Y.X. Yin ◽  
H.M. Wang

Wear-resistant Cu-based solid-solution-toughened Cr5Si3/CrSi metal silicide alloy with a microstructure consisting of predominantly the dual-phase primary dendrites with a Cr5Si3 core encapsulated by CrSi phase and a small amount of interdendritic Cu-based solid solution (Cuss) was designed and fabricated by the laser melting process using Cr–Si–Cu elemental powder blends as the precursor materials. The microstructure of the Cuss-toughened Cr5Si3/CrSi metal silicide alloy was characterized by optical microscopy, powder x-ray diffraction, and energy dispersive spectroscopy. The Cuss-toughened silicide alloys have excellent wear resistance and low coefficient of friction under room temperature dry sliding wear test conditions with hardened 0.45% C carbon steel as the sliding–mating counterpart.


2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744033 ◽  
Author(s):  
Qingjun Ding ◽  
Aihua Zhang ◽  
Gai Zhao ◽  
Hanmin Peng ◽  
Wei Gao

Cr2O3–TiO2 coatings with different proportions of La2O3 were deposited by atmospheric plasma spraying. The coatings were evaluated by hardness tester, surface roughness tester, SEM and wear tester. The experiment results showed that the addition of La2O3 could improve the microhardness and decrease porosity, wear rate and surface roughness of the coating. The coating containing 2 wt.% La2O3 had the best tribological properties. The dominant wear mechanism is a mixture of abrasive wear and adhesive wear. The microscopic analysis suggests that the addition of La2O3 could refine the microstructure and promote the formation of solid solution powder, and then affect the properties of coatings.


2020 ◽  
Vol 14 (4) ◽  
pp. 307-314
Author(s):  
Leszek Łatka ◽  
Mirosław Szala ◽  
Wojciech Macek ◽  
Ricardo Branco

2021 ◽  
Vol 1016 ◽  
pp. 88-93
Author(s):  
Vladimir Ulianitsky ◽  
Alexandr Shtertser ◽  
Igor Batraev ◽  
Maria Doubenskaia ◽  
Igor Smurov

Detonation spraying is used for the binary fuel spraying, C2H2/C3H8/O2 of WC/Co and Cr3C2/NiCr powder. The particles-in-flight temperature and velocity are calculated and optimized. Spraying distance is varied from 50 to 400 mm and substrate inclination relatively spraying direction is varied up to 60o. Coating properties: microstructure, microhardness, porosity, wear resistance are measured and it is found that binary fuel detonation spraying provides high coating quality. For example, for the WC/Co (88/12 wt%) coatings: porosity is less than 0.7%; microhardness is about 1500 HV300; ASTM G65 abrasion wear is 1.17 mm3/1000 rev when using a corundum powder as an abradant. For the Cr3C2/NiCr (75/25 wt%) coatings porosity is less than 1.7%, microhardness is about 800 HV300, and abrasion wear is 2.7 mm3/1000 rev. It is found that the coating performance does not decrease strongly with the substrate inclination up to 30o. The industrial applications include machinery, aircraft, petrol, gas turbines domains, etc.


2021 ◽  
Author(s):  
Maximilian Grimm ◽  
Rico Drehmann ◽  
Thomas Lampke ◽  
Susan Conze ◽  
Lutz-Michael Berger

Abstract This study investigates the microstructure and hardness of coatings produced by atmospheric plasma spraying using a commercial (Al,Cr)2O3 solid solution (ss) powder blended with various amounts of TiO2. The microstructures were analyzed using SEM, EDS, and XRD measurements. It was shown that blending with TiO2 reduces porosity and defect density while increasing deposition efficiency and microhardness. Small amounts of Ti in ss (Al,Cr)2O3 splats were detected in coatings prepared from blends with higher TiO2 content. Variations in aluminum and chromium content were also observed.


2011 ◽  
Vol 295-297 ◽  
pp. 256-259
Author(s):  
Jing Li ◽  
Jin Shan Zhao

Fe-28Al and Fe-28Al-10Ti alloys were prepared by mechanical alloying and hot pressed sintering. The mechanical properties and wear resistance were studied. The results show that Fe-28Al bulk material is mainly characterized by the low ordered B2 Fe3Al structure with some dispersed Al2O3 particles. The mechanical properties such as the hardness and strength of Fe-28Al-10Ti are significantly improved compared with Fe-28Al, which is attributed to the grain refinement and solid solution reinforcing with the addition of Ti element. The fracture mode is mainly the intergranular fracture. Fe-28Al-10Ti exhibits more excellent wear resistance than Fe-28Al, especially after long distance sliding wear test. There is difference in wear mechanisms of Fe-28Al and Fe-28Al-10Ti alloys. Under the load of 100N, there is obvious plastic deformation on the worn surface of Fe-28Al. Micro-crack and layer splitting occur on the surface of Fe-28Al. The main wear performance of Fe-28Al-10Ti is particle abrasion, the characteristics of which are micro cutting and micro furrows.


2012 ◽  
Vol 557-559 ◽  
pp. 1738-1741
Author(s):  
Zhi Hong Dong ◽  
Hong Yuan Fan ◽  
Yang Shun Qian

WC-Ni60 composite powders were mixed and deposited on Cr12MoV die steel by vacuum sintering technique. In order to prevent WC powders decomposition at the high temperature, Cr film was coated by D.C. magnetron sputtering and then prepared Cr/WC-Ni60 composite coating. The structure and composition and microhardness were measured by SEM and XRD and hardness tester. Tribological experiments were carried out on an abrasion machine. The results showed that thickness of Cr film is 3~5um. Some WC particles formed hard phases in nickel based solid solution to improve the hardness of the coatings. Due to Cr film preventing WC decomposition, Cr/WC-Ni coating had the higher hardness values compared with WC-Ni60 coating. The coating surface was uniform and compact and had no cracks. During the sliding wear, Cr/WC-Ni coating had a better wear resistance, and mass loss of wear was the least.


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