Oxidation behaviour of glass–quartz and glass–quartz–aluminium composite coatings on Ti–6Al–4V alloy

An Al-Si composite coating was synthesised on Ti-6Al-4 V alloy substrate by means of mechanical alloying. The as-synthesised coating had a composite structure. The effects of annealing treatment on the microstructure, the mechanical properties and the oxidation resistance of coating were investigated. The increase in annealing temperature was conductive to the formation of multilayered structure of the coating. The formation processes of the layers at different annealing temperatures were discussed. The coating annealed at 800°C had intermetallic layers, which improved the microhardness and wear resistance of the coating. The microhardness of the coating annealed at 800°C reached more than three times of the substrate microhardness. In addition, the coating annealed at 800°C had a thick inner protecting layer, which could retard the inward diffusion of oxygen during oxidation. The annealing of the coating at 800°C could improve the mechanical properties and oxidation resistance of the coating.

Section: Introductionmentioning

confidence: 99%

Effects of annealing on Al–Si coating synthesised by mechanical alloying

Chen

Feng

et al. 2017

“…As the amount of the glass matrix increased gradually, which is most probably caused by the amorphous B 2 O 3 (formed by oxidation of TiB 2 HCPs), the residual stress has decreased. One of the reasons for the gradually decreasing mass loss is the decreasing areas of stress due to the relaxation of residual stress and promotion of densification [36][37][38][39]. Besides, the presence of TiB 2 HCPs in the structure contributes to the development of wear resistance of the entire surface via the regional resistances in the surface by the properties of hardness and toughness.…”

Section: Resultsmentioning

confidence: 99%

TiB₂ embedded borosilicate coatings with improved wear resistance

Çöpoğlu

Karaahmet

Cengiz³

et al. 2021

State-of-the-art abrasion resistance of glass ceramic coatings (GCCs) is set by dense, low closed porosity, defect-and micro-stress-free microstructure since GCCs have low fracture toughness. Titanium diboride (TiB 2 ) is a ceramic material with relatively high strength and durability as characterized by the high melting point, hardness, and wear resistance. In this study, the effect of mill additive TiB 2 hard ceramic particles (HCP) on GCCs was investigated. The precursor glass ceramic system of SiO 2 -Na 2 O-B 2 O 3 -CaO-Fe 2 O 3 was selected. The wear resistance of the GCCs was tested simultaneously by Taber Abraser and by a tribometer. B 2 O 3 , which is formed by the oxidation of TiB 2 , fills the pores and the microcracks on the surface, thus reducing the stress areas and increasing the wear resistance. Increasing the TiB 2 HCP addition yielded a decrease in mass loss of about 81%, wear rate of about 82% and increase in the coefficient of friction of 15%.

“…Quartz-containing samples were found to have the lower abrasion resistance and greater mass loss values. This is due to an increase in the number of pores and stress points with the presence of quartz, which is caused by a coefficient of thermal expansion mismatch between the quartz particles and the GC matrix [42][43][44].…”

Section: Abrasion Testmentioning

confidence: 99%

Abrasion-resistant CMAS glass-ceramic coatings incorporated with B₄C particles

Çöpoğlu

Karaahmet

Çiçek

2022

One of the most significant mechanical characteristics of glass-ceramic coatings (GCCS) is abrasion resistance, which is particularly pertinent when contamination from the coated metallic surface is not desired. The influence of incorporating boron carbide (B 4 C) as a hard particle into the CaO-MgO-Al 2 O 3 -SiO 2 GCC on the abrasion resistance was examined in this study. A PEI Abraser was used to evaluate the abrasion resistance over 5000 cycles, with mass loss recorded every 1000 cycles. Mass loss following the abrasion test was observed to decrease when the amount of added B 4 C was increased, indicating that the abrasion resistance was enhanced by B 4 C addition. The addition of 16 wt-% B 4 C has had the strongest interface among the matrix/B 4 C particles, resulting in higher abrasion resistance due to reduced crack formation and porosity, and yielded a decrease in mass loss of about 54%, colour change of <2 in terms of ΔE and gloss change about 40%.