A Review of Clearance Control Wear Mechanisms for Low Temperature Aluminium Silicon Alloys

Abstract

Aluminium silicon alloys have shown favourable properties when used as the matrix for abradable coatings in low pressure compressors of gas turbines [1 and 2]. This paper aims to describe the wear mechanisms found in aluminium silicon based abradables. To this end three thermally sprayed coatings are investigated. Aluminium silicon polyester, aluminium silicon-graphite and the most recently developed, aluminium silicon-hexagonal boron nitride (hBN) examined here are amongst a few of these materials. To be able to design materials to functi?n in as wide a parameter range as possible, a test ng simulating engine mechanisms is required. Tests were conducted using titanium blades at velocities ranging from 250 - 450 m/s, temperatures of ambient to 450°C and controlled incursion rate of 5, 50 and 500 µm/s. The data obtained from these tests is best interpreted in the form of wear maps which characterise the seal performance and therefore are of use to engine and material designers.

Study on Wear Mechanism of an AlSi–Hexagonal Boron Nitride Abradable Seal Coating

“…The blade tip velocity was selected to identify how this influenced the blade tip interaction with the abradablecoating. [5].The coatingcharacteristics of the AlSi-hBN are shown in Table 2. Flat Ti-6Al-4V blades were manufactured with a nominalbladelengthof 10mm and thicknessof 0.7mm.…”

High-Speed Rubbing Behavior Between Nickel-Based Superalloy Blades and Ceramic-Based Abradable Coatings

“…Ghasripoor et al [8] studied the damage mechanisms of three aluminium-based sealing coatings. They found that, in most cases, blade damage was reduced or replaced by coating adhesion.…”