Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

Abstract

Abstract:To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe 59 Cr 12 Nb 5 B 20 Si 4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF) spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K), two times lower than the reference stainless steel coating (5.85 W/(m·K)), indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 • C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 • C and decreasing at 400 • C.

Microstructure, Wear Behavior and Corrosion Resistance of WC-FeCrAl and WC-WB-Co Coatings

“…The presence of cracks on the metallographic sections could be explained as a consequence of mixture events that can occur in coatings during thermal cyclic loading [6,8,12,16,17,[25][26][27]:…”

“…Thermally sprayed coatings are often used to increase the resistance of the parent material against corrosion and wear [3][4][5][6][7][8][9][10][11][12][13][14][15]. The desired properties of coatings applied by the high-velocity oxygen fuel (HVOF) method also include high density and good adhesion, which are characterized by the ability to form coatings with a small portion of oxides and phase transformations [16][17][18][19].…”

Novel Fe-Based Amorphous Composite Coating with a Unique Interfacial Layer Improving Thermal Barrier Application

“…Metal-based thermal barrier coatings (MBTBCs) have attracted great interest during the past few years, due to their potential in developing advanced vehicle engines by protecting aluminum alloy components against relatively high temperature, wear failure, and thermal shock. − Meanwhile, these coatings provide a major benefit that meets the urgent need to enhance the heat energy conversion of vehicle engines; for instance, an increase in the temperature of the piston crown’s surface could decrease the temperature difference between the wall and gas, thereby enhancing the power efficiency . The concept of MBTBCs greatly depends on the fundamental demand of low thermal conductivity, which deviates from the understanding of conventional metals, which are generally regarded as good conductors.…”

“…The concept of MBTBCs greatly depends on the fundamental demand of low thermal conductivity, which deviates from the understanding of conventional metals, which are generally regarded as good conductors. Metallic glasses, accordingly, have come into sight owing to their high defect density originating from their disordered structure, which can scatter heat carriers intensively and result in abnormally low thermal conductivity. ,,− In this group, Fe-based amorphous alloys preferably satisfy engineering needs in view of their combination of a relatively high glass-forming ability and crystallization temperature, excellent wear resistance, and obvious cost efficiency. − Some Fe-based amorphous coatings prepared by high-frequency induction plasma spraying (IPS), high-velocity oxygen-fuel spraying (HVOF), atmospheric plasma spraying (APS), and wire-arc spraying (AS) present the expected low thermal conductivities in the range of 2–3 W/mK, − , thus making them proper candidates for MBTBCs.…”

Effects of V and Cr on Laser Cladded Fe-Based Coatings

“…Fe-based alloy powder has certain advantages such as the wide range of sources, low price, and closing to the composition of the substrate and acceptable compatibility [15]. To meet the different requirements under certain circumstances, alloying elements, such as vanadium, titanium, niobium and chromium, are added into Fe-based powder to manufacture different parts with diverse properties.…”