A Comparative Study of Cr₂O₃ Thin Films Obtained by MOCVD using Three Different Precursors

Abstract

Thin films of chromia (Cr 2 O 3 ) for anti-wear protection were grown by metal-organic (MO)CVD on AISI 304 stainless steel, soda-lime glass, and (001) silicon substrates. The structural, morphological, and chemical compositions were compared for films grown by using three different, commercial, organochromium compounds; Cr(CO) 6 (1), Cr(III) (hexafluoroacetylacetonate) (2), and tris(2,2,6,6-tetra-methyl-3,5-heptanedionato) chromium (III) (3). The depositions were performed using a hot-wall reactor at 500 C, under 3 torr, using N 2 as the carrier gas and O 2 mixed with water vapor as the reactant gas. The films were analyzed by X-ray diffraction (XRD), atomic force microscopy (AFM), Rutherford backscattering (RBS), nuclear reaction analysis (NRA), elastic recoil detection (ERD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared (FTIR) spectroscopy. The films grown with all three precursors on all three substrates were crystalline with hexagonal Cr 2 O 3 eskalonite structure. FTIR and XPS measurements confirmed the XRD results, showing IR absorption bands characteristic of Cr 2 O 3 and an oxidation state +3 of chromium. The highest growth rate was obtained with precursor (1) (20 nm min ±1 ). Films grown with (1) on stainless steel were analyzed by nanoindentation measurements and scratch test to determine the hardness and the film adhesion.

Oxide Formation, Morphology, and Nanohardness of Laser‐Patterned Steel Surfaces

“…Although, this might be explained by the well-known indentation size effect, [43,44] XPS and APT determined oxide layers with thicknesses in the range of the used contact depths. [46][47][48][49][50] For larger contact depths (d > 15 nm), the hardness of each sample remains nearly constant. [45] Therefore, it can be assumed that the harder oxide layer significantly contributes to measurements at small contact depths.…”

The Effect of Deposition Parameters on the Structure and Mechanical Properties of Chromium Oxide Coatings Deposited by Reactive Magnetron Sputtering

“…Bulk Cr 2 O 3 is one of the hardest oxides, with a hardness of 29.5 GPa [1][2][3][4], and can be deposited as a protective coating for many purposes, due to its high wear resistance, low coefficient of friction, and excellent corrosion resistance [5][6][7]. Many methods, including plasma-spray [8][9][10], sputtering [11,12], chemical vapor deposition (CVD) [13], and pulsed laser deposition [14], have been used to produce Cr 2 O 3 coatings. However, among them, only sputtering techniques have so far been successful in producing Cr 2 O 3 coatings with a hardness value close to that of bulk Cr 2 O 3 [3,12,15,16].…”

Synthesis, characterization, and growth mechanism of α-Cr2O3 monodispersed particles

“…For example, it is an important refractory material due to its high melting temperature of about $ 2435 1C [4]. High corrosion and oxidation resistance [5], hardness and antiferromagnetic properties [6], enable its use as a coating material for thermal protection [7], as intermediate layers in corrosion-resistant applications on semi-conductors and metals [8], as an active tunneling barrier or pinning system for spintronic applications [9], as a pigment powder with high NIR reflectance [10], and widely used for solar absorber applications [11].…”