Studies on the growth mechanism of aluminide coating on K444 alloy surface by chemical vapor deposition

Abstract

The studies of the growth mechanism of aluminide coatings by chemical vapor deposition (CVD) is an important prerequisite for optimizing the thermal protection properties of aluminide coatings and improving the CVD process parameters; however, the current research on the growth mechanism of CVD aluminide coatings on nickel-based alloys is relatively limited, and there is a lack of systematic studies in this area. In this work, aluminide coatings were prepared on the surface of nickel-based superalloys by the CVD method, and elemental diffusion and microstructure effects between coating and substrate at different deposition temperatures and times, as well as the growth kinetics and formation mechanism of CVD aluminide coatings were investigated. The results showed that the coating prepared on the surface of K444 nickel-based high-temperature alloy by CVD was an externally diffused aluminide coating with a bilayer structure: the outer layer of the coating was the β-NiAl phase. The interdiffusion layer was mainly composed of nickel-aluminum compounds, carbides, and topologically close-packed phase. The growth of the CVD aluminide coating was mainly controlled by the grain boundary diffusion mechanism.

Recent Advances in the Deposition of Aluminide Coatings on Nickel-Based Superalloys: A Synthetic Review (2019–2023)

“…Recently, some new approaches were reported to increase the operating temperature of NiAl coatings above 1200 °C. These involve the addition of platinum, palladium, zirconium and hafnium [44,46,49,51]. One should mention that the NiAl coatings deposited on MAR 247 exhibited excellent adherence to the base material, as even after the specimen subjected to cyclic loading fractured, no cracks were detected in the area near the fracture (Figure 6a) and the coating was still well connected with the base material (Figure 6b).…”

“…In this process, a precursor gas is introduced into a chamber, where it reacts to form a solid film on the substrate surface (Figure 4). Since CVD is a commonly used process in the industry, the recent advances related to this deposition technique are mainly related to its successful application on different grades of nickel-based superalloys (Table 3) [1][2][3]5,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. It was reported that NiAl coatings were effectively deposited on MAR 247 [1-3,37,39,43,49-51], Inconel 740 [5], Inconel 738 [38,45], Inconel 713 [39,41,52], CMSX 4 [42,44,46], Inconel 100 [39], K-403 [47], K444 [51], pure nickel [48] and even on additively manufactured Haynes 282 [55].…”

“…Since CVD is a commonly used process in the industry, the recent advances related to this deposition technique are mainly related to its successful application on different grades of nickel-based superalloys (Table 3) [1][2][3]5,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. It was reported that NiAl coatings were effectively deposited on MAR 247 [1-3,37,39,43,49-51], Inconel 740 [5], Inconel 738 [38,45], Inconel 713 [39,41,52], CMSX 4 [42,44,46], Inconel 100 [39], K-403 [47], K444 [51], pure nickel [48] and even on additively manufactured Haynes 282 [55]. A significant fraction of the phase was retained in the coating after cyclic oxidation behavior in air +10% H2O at 900 °C for 1000h [33] 602 CA NiAl + Ge Maintains its integrity and protective behavior at 1200 °C [34] Hastelloy-X + NiCoCrAlY SiAl NiCoCrAlY (HVOF)/silico-aluminide (slurry) coating is more resistant to high-temperature oxidation at 1000 °C than NiCoCrAlY coating [35] Inconel 738 Ni/Cr/Ti-Al…”

“…Since CVD is a commonly used process in the industry, the recent advances related to this deposition technique are mainly related to its successful application on different grades of nickel-based superalloys (Table 3) [1][2][3]5,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. It was reported that NiAl coatings were effectively deposited on MAR 247 [1-3,37,39,43,49-51], Inconel 740 [5], Inconel 738 [38,45], Inconel 713 [39,41,52], CMSX 4 [42,44,46], Inconel 100 [39], K-403 [47], K444 [51], pure nickel [48] and even on additively manufactured Haynes 282 [55]. One can observe that NiAl coatings applied on different nickel-based superalloys have mainly been used to improve the corrosion resistance against high temperatures ranging between 1000 °C [5,38,39,43,44,46,…”

“…One should mention that the NiAl coatings deposited on MAR 247 exhibited excellent adherence to the base material, as even after the specimen subjected to cyclic loading fractured, no cracks were detected in the area near the fracture (Figure 6a) and the coating was still well connected with the base material (Figure 6b). Recently, some new approaches were reported to increase the operating temperature of NiAl coatings above 1200 • C. These involve the addition of platinum, palladium, zirconium and hafnium [44,46,49,51].…”