The Influence of the Powder Characteristics on 316L Stainless Steel Coatings Sprayed by Cold Gas Spray

Abstract

Thermally sprayed 316L stainless steel coatings are commonly used on metallic structures due to their corrosion and wear resistance when compared to carbon steel. Cold Gas Spray (CGS) is a convenient thermal spray process to deposit 316L coatings, producing thick and very dense coatings, with almost no deleterious changes on the feedstock properties to the coating condition. The powder characteristics have influence on the microstructure of the coating, such as porosity and oxide contents, which alter its corrosion and wear behavior. CGS is an efficient technique to reduce the problems associated with material melting commonly found in other conventional thermal spray methods. In this work, different 316L powders, produced by different manufacturers, were deposited by CGS, applying the same equipment and parameters, with the objective to evaluate the relation between the powders’ characteristics and coating properties. Their microstructure, adherence, hardness, as well as the performance on corrosion and wear testing were evaluated. The water atomized powders presented in general better results than gas atomized powders.

Improving the Wear and Corrosion Resistance of Maraging Part Obtained by Cold Gas Spray Additive Manufacturing

“…A significant difference in these parameters can be observed between the sprayed materials and the bulks, with the 316L bulk as the noblest material, −179.80 mV, and the worst behavior for C-steel bulk, −753.97 mV. These results are consonant with those presented in the literature, −239 mV [16] and −260 mV [57] for 316L bulk and −726 mV [46] and −719 mV [58] for C-steel. Regarding the sprayed materials, their results were lower than the 316L bulk stainless steel ones and higher than the C-steel bulk ones.…”

“…The mean CoF values after the wear regimen stabilized are indicated in Table 4. The value indicated for the reference material 316L bulk, 0.67, is close to the value presented in the literature, 0.7 [16,49]. The CGS MAM maraging presented the highest CoF, 0.86, while the WC-10Co4Cr had the lowest, 0.14, among the evaluated materials.…”

“…The images of coatings' cross-sections are presented in Figure 4, where it is possible to observe that the particles deformed due to their impact at high velocity in CGS MAM maraging, resulting in a dense material, which was revealed by the etching (Figure 4a). The periphery of the maraging particles had severe grain deformation, while the center of the particles remained with an equiaxial microstructure, which is typical for CGS sprayed layers [16]. The porosity was calculated as a mean of 10 image analyses, and Figure 4 does not represent this average porosity value, which is indicated in Table 3.…”

“…Regarding the materials applied by CGS MAM, the literature reports the production of Cu alloys, Al alloys, Ti alloys, Ni alloys, and steel parts [6,7,[9][10][11]15,16]. Recently, researchers have devoted efforts to CGS maraging, which is a material with a good combination between high strength, toughness, and ductility, working well in a harsh environment [17,18].…”

Metal Knitting: A New Strategy for Cold Gas Spray Additive Manufacturing

“…The literature presents the application of CS for AM for a large number of materials, highlighting the components made from 316L stainless steel [ 10 , 11 , 12 , 13 , 14 ], Cu alloys [ 15 , 16 , 17 ], and Ti alloys [ 18 , 19 , 20 , 21 ], but not limited to them since Al alloys [ 21 , 22 , 23 , 24 ], Ni superalloys [ 25 , 26 ], maraging steel [ 27 , 28 , 29 ], and many others have also been studied. Moreover, these CSAM components have interested different sectors, such as aerospace, automotive, energy, medical, and marine sectors, among others [ 8 , 30 ].…”