Corrosion resistance of nanostructured TiB2 films in 3% NACl solution

Abstract

The paper examines the corrosion behavior of amorphous TiB 2 films 70-250 nm in thickness and amorphous-crystalline films with crystals 15-90 nm in size in 3% NaCI solution. It is shown that the corrosion resistance and passivation anodic potential increase with thickness of TiB 2 amorphous films. It is also established that TiB 2 films are oxidized through pitting corrosion. The corrosion instability of amorphous films is mainly due to their interaction with impurity (in particular, oxygen and carbon) structural inhomogeneities and of amorphous-crystalline films due to the interaction with amorphous-crystalline boundaries. The corrosion resistance of amorphous TiB 2 films is approximately 4000 times higher than that of bulk powder material and 8 to 10 times higher than that of amorphous-crystalline films.Diborides of transition metals are radically new materials in thin-film technology. The unique combination of high conductivity, high heat resistance, exceptional chemical inertness, and low electron work function makes them unique candidates for use in heat-resistant high-conductivity layers, Schottky contacts with n-Si and n-GaAs, and diffusion barriers in multilayer contacts with semiconductors [1, 2]. The corrosion properties of ceramic films of titanium nitride and boride have recently been of increasing interest. This is because these compounds are promising thin-film protective coatings [3,4].However, there are no publications on the research of the corrosion resistance of thin nanostructured TiB 2 films in liquid corrosive media.The objective of this paper is to study the corrosion behavior of nanostructured TiB 2 films in 3% NaCl solution. To ascertain the mechanism of the process, the microstructure of the films after corrosion tests was examined.The corrosion tests were conducted using the electrochemical method of plotting potentiodynamic polarization curves (PI-50-1 potentiostate, scan rate 0.5 mV/sec). The anodic potentials were measured in 3% NaCl solution, which is conventionally used in corrosion tests (sea-water imitation). The potentials in this paper are relative to the standard reference silver-silver chloride electrode.

Nanostructured titanium, zirconium and hafnium diborides: the synthesis, properties, size effects and stability

“…Electrochemical properties of amorphous nanocrystalline TiB 2 films in 3% NaCl solution simulating the influence of sea water were investigated. 120,121 The samples studied were shown to have a great advantage over coarse-grained samples; also, a pitting corrosion was revealed.…”

Magnetron Sputter Epitaxy of CrB2/TiB2 Diboride Superlattice Thin Films

“…However, SLs research on TM diborides is an unexplored area despite extensive studies over the last decades on monolithic TM diboride thin films. Single layer diborides show high mechanical strength [25][26][27], oxidation and corrosion resistance [28][29][30], relatively low electrical resistivity [31][32][33][34], tribological properties [35,36], and high thermal and chemical stability [32,37]. Comparing to nitride and carbide SLs with cubic structures, there are fewer possibilities for heteroepitaxy to grow SLs from two diboride materials with hexagonal crystal structures.…”

Microstructure and Materials Properties of Understoichiometric TiBx Thin Films Grown by HiPIMS

“…This hard ceramic has attractive properties motivating this interest, [1][2][3] including high thermal and electrical conductivity, [4] good thermal and chemical stability [5] as well as good oxidation and mechanical erosion resistance. [6][7][8] While the most common method to grow TiB2 is direct-current magnetron sputtering from compound targets, several reports show other approaches in choice of synthesis, including electroplating, arc-PVD, pulsed DCMS, RF-sputtering, and HiPIMS. [9][10][11][12][13][14][15][16] DCMS typically produce over-stoichiometric material, with a B/Ti ratio in the range of 2.4 to 3.5.…”