Thermal spray coating of aluminum nitride utilizing the detonation spray technique

2002 ◽  
Vol 17 (10) ◽  
pp. 2514-2523 ◽  
Author(s):  
L. Rama Krishna ◽  
D. Sen ◽  
Y. Srinivasa Rao ◽  
G. V. Narasimha Rao ◽  
G. Sundararajan
Keyword(s):  
Aluminum Nitride ◽  
Phase Distribution ◽  
Steel Substrate ◽  
Spray Coating ◽  
Wear Test ◽  
Deposition Process ◽  
Tribological Performance ◽  
Spray Parameters ◽  
Pure Alumina ◽  
Detonation Spray

The main objective of this work is to examine the feasibility of depositing aluminum nitride (AlN) powders, synthesized using self-propagating high-temperature synthesis, on a mild steel substrate using the detonation spray coating technique. Thick coatings produced by utilizing the AlN powder were obtained at four different oxygen–acetylene ratios and analyzed for microstructure, microhardness, porosity, indentation fracture toughness, and phase distribution. The AlN powder particles were found to be undergoing oxidation during the deposition process. The interrelationship between the spray parameters and the extent of oxidation of AlN during the coating process was investigated. Tribological performance of the coatings was evaluated using a dry sand abrasion test and a pin-on-disc sliding wear test. The mechanical and tribological properties of the above four coatings were compared with pure alumina (Al2O3) coatings. The correlation between the structure of the coatings and their tribological performance was also established.

Tribological Properties of Flame Sprayed Hexagonal Boron Nitride/Polyetheretherketone Coatings

2011 ◽  
Vol 410 ◽  
pp. 333-336 ◽  
Author(s):  
Jirasak Tharajak ◽  
Tippaban Palathai ◽  
Narongrit Sombatsompop
Keyword(s):  
Boron Nitride ◽  
Tribological Properties ◽  
Hexagonal Boron Nitride ◽  
Steel Substrate ◽  
Spray Coating ◽  
Wear Test ◽  
Flame Spray ◽  
Composite Powders ◽  
Wear Rates ◽  
Peek Composite

Hexagonal boron nitride (h-BN)/polyetheretherketone (PEEK) composite powders were deposited on carbon steel substrate via the flame spray coating technique. The content of hexagonal boron nitride with a mean particle size of 0.5 micrometer was varied from 2 to 8 wt% in this work. Tribological properties, namely specific wear rate and friction coefficient, at room temperature, 100 °C and 200°C were performed using Ball-on-Disc sliding wear test. At elevated temperature, h-BN could result in marked decrease in the friction coefficients and specific wear rates.

In situ monitoring of cracking behaviors of plasma-sprayed coatings by the laser acoustic emission technique

2009 ◽  
Vol 24 (10) ◽  
pp. 3182-3189 ◽  
Author(s):  
Koichi Taniguchi ◽  
Manabu Enoki ◽  
Makoto Watanabe ◽  
Seiji Kuroda ◽  
Kaita Ito
Keyword(s):  
Acoustic Emission ◽  
Thermal Spray ◽  
Steel Substrate ◽  
Spray Coating ◽  
Deposition Process ◽  
Maximum Principal Stress ◽  
In Situ Monitoring ◽  
Alumina Coating ◽  
Cooling Period

Multichannel acoustic emission (AE) measurements by four laser interferometers were developed and applied during a plasma-spray coating process that is known as being a high-temperature process and an extremely noisy environment in both mechanical and electrical domains. The AE signals could be successfully detected during the cooling period after the deposition, and it was clearly indicated that a higher preheating temperature resulted in the improvement of bonding between splats and/or at the interface of the coating and the substrate. The maximum principal stress generated during the deposition process was calculated by the transient heat and stress analysis and the obtained AE events. The critical stress for crack initiation of the alumina coating on a steel substrate with an NiCr bond coat layer was estimated as 30∼45 MPa. The developed techniques were shown to be a potential tool for in situ monitoring of the thermal spray process, by which an increase in the reliability of thermal spray coatings can be expected.

Optimization of Thermal Spray Parameters of NiAl/Cr2C3 Coating by Taguchi Method

2019 ◽  
Vol 295 ◽  
pp. 9-14 ◽  
Author(s):  
M. Tahari ◽  
B. Luo ◽  
J. Geng ◽  
D. Jing ◽  
M. Hatami
Keyword(s):  
Wear Resistance ◽  
Thermal Spray ◽  
Feed Rate ◽  
Spray Coating ◽  
Wear Test ◽  
Thermal Spray Coating ◽  
Spray Parameters ◽  
Spray Distance ◽  
Powder Feed Rate ◽  
Powder Feed

In this study the effect of thermal spray process on wear resistance of NiAl/Cr2C3 thermal spray coating has been investigated. For this purpose the NiAl power mixed with 10 %wt. Cr2C3 powder and milled for 1 hrs at argon atmosphere. The APS parameters such as voltage (V), current (A), spray distance (mm), powder feed rate (gr/min), were optimize using a response surface methodology. For investigation effect of spray parameters on quality of coatings, the porosity and wear resistance of coatings analyzed with SEM and pin on disk wear test. Results show that increase of voltage and current are more effective other parameters. Increasing of powder feed rate and spray distance raised porosity of coatings intensively.

Study of the Cr3C2–NiCr detonation spray coating

2000 ◽  
Vol 130 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Jun Wang ◽  
Li Zhang ◽  
Baode Sun ◽  
Yaohe Zhou
Keyword(s):  
Spray Coating ◽  
Detonation Spray ◽  
Detonation Spray Coating

Morphology and Mechanical Properties of a Composite Coating by Electrostatic Dry Spray Method

2021 ◽  
Vol 886 ◽  
pp. 168-174
Author(s):  
Mohanad N. Al-Shroofy ◽  
Hanna A. Al-Kaisy ◽  
Rabab Chalaby
Keyword(s):  
Composite Coating ◽  
Steel Substrate ◽  
Low Carbon Steel ◽  
Spray Coating ◽  
Manufacturing Cost ◽  
Low Carbon ◽  
Spray Method ◽  
Coating Layers ◽  
Al Powder ◽  
Electrostatic Spray

Powder spray coating was used for many applications such as paint decoration and protection against corrosive environments. The electrostatic spray method is used to lower the manufacturing cost and the environmental effect during the production process. It is done by electrostatic device and spray gun to create a layer on the substrate to play a protective role. Different dry powders were mixed to form a composite mixture consisted of Al2O3 and SiC or ZrSiO4 with Al powder as a binder. The powders mixture was deposited by electrostatic spray technique with a high voltage of 15 kV on a low carbon steel substrate of (40 x 10 x 4) mm in dimensions. Two groups of mixtures were used to form the coating layers. Powders of Al2O3 with (20 and 40) weight percent (wt%) of SiC as the first group and (20 and 40) wt% of ZrSiO4 as the second group were used. 5 wt% of Al powder was added as a binder, and the samples were heat treated at 900 C° for 2 hours. A detailed characterization of the composite coating layers was performed using XRD, SEM, and EDX, as well as, micro-hardness measurements. The obtained surface composite layers were smooth and having good particle distribution which leads to enhance roughness values (Ra). Furthermore, the hardness increased with increasing the amount of carbide and zirconia, and the obtained layers show no presence of defects or cracks.

scholarly journals Microstructural and Corrosion Behavior of High Velocity Arc Sprayed FeCrAl/Al Composite Coating on Q235 Steel Substrate

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 542 ◽  
Author(s):  
Ndumia Joseph Ndiithi ◽  
Min Kang ◽  
Jiping Zhu ◽  
Jinran Lin ◽  
Samuel Mbugua Nyambura ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
High Velocity ◽  
Steel Substrate ◽  
Arc Spraying ◽  
Spray Parameters ◽  
Q235 Steel ◽  
Electrochemical Tests ◽  
Al Composite ◽  
Al Coating

High velocity arc spraying was used to prepare FeCrAl/Al composite coating on Q235 steel substrate by simultaneously spraying FeCrAl wire as the anode and Al wire as the cathode. The composite coating was sprayed with varying voltage and current to obtain optimum coating characteristics. FeCrAl coating was also prepared for comparison purposes. The surface microstructure of the coatings was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The average microhardness of the coatings and the substrate was analyzed and compared. Corrosion resistance was investigated by means of electrochemical tests. The image results showed that a lamellar structure consisted of interwoven layers of FeCrAl and Al. Al and FeCr constituted the main phases with traces of oxides and AlFe intermetallic compounds. The average porosity was reduced and microhardness of the coatings was improved with increasing voltage and current. The FeCrAl/Al coating formed alternating layers of hard and ductile phases; the corrosion resistance of the coatings in the sodium chloride (NaCl) solution depended on the increase in Al content and spray parameters. The corrosion resistance tests indicated that FeCrAl/Al coating had a better corrosion resistance than the FeCrAl coating. FeCrAl/Al can be used to coat steel substrates and increase their corrosion resistance.

Splashing of Nickel Droplets During Plasma Spraying

2000 ◽  
Author(s):  
V. Pershin ◽  
I. Thomson ◽  
S. Chandra ◽  
J. Mostaghimi
Keyword(s):  
Substrate Temperature ◽  
Nickel Powder ◽  
Steel Substrate ◽  
Spray Coating ◽  
Building Blocks ◽  
Thermal Spray Coating ◽  
Substrate Heating ◽  
Polished Stainless Steel ◽  
Plasma Sprayed ◽  
Droplet Impacts

Abstract Individual splats are the building blocks of any thermal spray coating. Near the coating-substrate interface, they affect coating properties like adhesion strength. This article examines the effect of substrate heating on droplet splashing. Nickel powder was plasma-sprayed onto a polished stainless steel substrate at various temperatures and the resulting splats were analyzed. Droplet splashing was observed experimentally for three different cases: low substrate temperature, high substrate temperature, and droplet-splat interaction. Mechanisms for splashing were explained with the help of computer-generated nickel droplet impacts. The article proposes that the jetting of molten metal is not triggered by the formation of a central splat but rather a solidified ring on the periphery of the splat. It was observed that, on substrates below 350 deg C, splashing is triggered by solidification at the edge of the spreading droplet. Interactions with previously deposited splats also cause droplets to splash.

THE EFFECT OF COATING THICKNESS ON FATIGUE PROPERTIES OF STEEL THERMALLY SPRAYED WITH Ni-BASED SELF-FLUXING ALLOY

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3599-3604 ◽  
Author(s):  
HIROYUKI AKEBONO ◽  
JUN KOMOTORI ◽  
HIDETO SUZUKI
Keyword(s):  
Fatigue Strength ◽  
Thermal Spray ◽  
Coating Thickness ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Fatigue Cracks ◽  
Spray Coating ◽  
Maximum Size ◽  
Thermal Spray Coating ◽  
Fatigue Properties

The Thermal spraying is one of the most popular surface coating techniques. To achieve the most efficient use of this technique in practice, it is very important to clarify the fatigue properties of steel coated with a thermal spray coating. In this study, to clarify the effects of coating thickness on the fatigue properties of the steel substrate, three types of sprayed specimens with different coating thickness (0.2, 0.5 and 1.0mm) were prepared and fatigue tests were carried out. Coating thickness strongly affected the fatigue properties; the thinner the coating thickness, the higher the fatigue strength. Fatigue crack propagation behaviors were observed. Accordingly the fatigue cracks propagated through many defects on the coated surface. The sizes and number of the coating defects were determined by coating thickness; the thicker the coating thickness, the larger the defect and number. Therefore, the sprayed specimens with thinner coatings indicated higher fatigue strength. Furthermore, estimations of the fatigue strength were performed by using Murakami's equation. The fatigue strengths of thermal spray coated specimens were estimated by three parameters; (i) maximum size of coating defects estimated by statistics of extreme value, (ii) hardness of the matrix and (iii) volume fraction of coating defects.

Sign in / Sign up

Export Citation Format

Share Document