Bonding Characteristics and Chemical Inertness of Zr–Si–N Coatings with a High Si Content in Glass Molding

Abstract

High-Si-content transition metal nitride coatings, which exhibited an X-ray amorphous phase, were proposed as protective coatings on glass molding dies. In a previous study, the Zr-SiN coatings with Si contents of 24-30 at.% exhibited the hardness of Si 3 N 4 , which was higher than those of the middle-Si-content (19 at.%) coatings. In this study, the bonding characteristics of the constituent elements of Zr-SiN coatings were evaluated through X-ray photoelectron spectroscopy. Results indicated that the Zr 3d 5/2 levels were 179.14-180.22 and 180.75-181.61 eV for the Zr-N bonds in ZrN and Zr 3 N 4 compounds, respectively. Moreover, the percentage of Zr-N bond in the Zr 3 N 4 compound increased with increasing Si content in the Zr-SiN coatings. The Zr-N bond of Zr 3 N 4 dominated when the Si content was >24 at.%. Therefore, high Si content can stabilize the Zr-N compound in the M 3 N 4 bonding structure. Furthermore, the thermal stability and chemical inertness of Zr-SiN coatings were evaluated by conducting thermal cycle annealing at 270 • C and 600 • C in a 15-ppm O 2-N 2 atmosphere. The results indicated that a Zr 22 Si 29 N 49 /Ti/WC assembly was suitable as a protective coating against SiO 2-B 2 O 3-BaO-based glass for 450 thermal cycles.

Mechanical Properties and Oxidation Behavior of Multilayered Hf–Si–N Coatings

“…The Hf 4f signals consisted of Hf4N3, HfN, Hf3N4 and Hf-O (Figure 10c), the intensity ratio of which was 23:26:40:11 for Hf4N3:HfN:Hf3N4:Hf-O. The absence of metallic Hf 0 and the presence of free Si and increased amounts of Hf3N4 bonds related to those of the Hf48Si3N49 coatings implied that the amount of Si-N bonds was saturated and Hf tended to form the Hf3N4 compound accompanied by a high Si content, which was similar to that reported for the Zr-Si-N coatings [39]. Zr3N4 and Hf3N4 with the Th3P4 structure have been reported [27,28,40].…”

Effect of Silicon Content in Functional Properties of Thin Films

“…Different works have reported that the main mechanisms that allow to explain the hardness enhancement in the nanocomposites are three: (i) the dislocation-induced plastic deformation when the crystalline size is >10 nm, (ii) the nanostructure of materials when the crystalline size is ≤ 10 nm, and (iii) cohesive force between atoms when the crystalline size is <10 nm. However, when the thickness of amorphous phase is larger than the crystalline size, the nanohardness of the films decreases due to a deformation mechanism reported as grain boundary sliding [24,94].…”

“…the SiN x phase thickness is larger than the crystallite size of the ZrN phase, the nanohardness of the films decreases due to an increase of the volume fraction of the amorphous soft phase. The deformation mechanism, in this case, is grain boundary sliding [24].…”

“…Among all these compounds, we find that the transition metal nitrides (MeN) have been widely used in mechanical applications due to their high hardness and wear resistance [2,[13][14][15][16]. However, it has been found that the addition of a third element may improve the physical and chemical properties of MeN due to a change that this new element generates in the microstructure of these materials [1,[17][18][19][20][21][22][23][24][25][26][27][28][29][30]. These structures are called nanocomposite, and there are two different groups of hard nanocomposite films, for instance: (i) crystalline/amorphous nanocomposites and (ii) crystalline/crystalline nanocomposites.…”

Mechanical Properties of Zr–Si–N Films Fabricated through HiPIMS/RFMS Co-Sputtering

“…In our previous studies on Ta-Si-N [12], Nb-Si-N [13] and Zr-Si-N [14] coatings, fabricated using direct-current magnetron sputtering (DCMS) (introducing high Si contents into nitrides), formed an amorphous structure on X-ray and improved the oxidation resistance; although their mechanical properties deteriorated. Therefore, high-Si-content Ta-Si-N [15] and Zr-Si-N [16] coatings are applied for glass molding dies, which are operated under a low oxygen-containing atmosphere at approximately 600 • C. By contrast, the low-Si-content Zr-Si-N coatings exhibited a crystalline structure accompanied with a hardness level of 23-24 GPa and a compressive stress of less than 2 GPa [14]. High-power impulse magnetron sputtering (HiPIMS) [17,18] was recommended to grow films with a dense structure, high hardness and high residual compressive stress [19,20].…”