Solid-Particle Erosion of High-Technology Ceramics (Si3N4, Glass-Bonded Al203, and MgF2)

Abstract

Four “engineering” ceramics were subjected to impact (single particle) and erosion (multiple impacts) under conditions which simulate a natural dust environment in the subsonic velocity regime. The target materials are hot-pressed silicon nitride (Si3N4), reaction-bonded Si3N4, a glass-bonded aluminum oxide (Al2O3), and hot-pressed magnesium fluoride (MgF2). Tests were performed with six narrow size ranges of natural quartz between 10 and 385 μm average, and five velocities for each particle size. Hot-pressed Si3N4 was also impacted with silicon carbide (SiC) under the same particle size-velocity conditions. The results are discussed in terms of current erosion and impact models by considering particle size-velocity dependencies, appearance of the impact damage, and the basic properties and structure of the targets. Under these erosion conditions, the four target materials exhibited widely different behavior not only in absolute amount of material removed, but also in mechanism of removal. The systems hot-pressed Si3N4-SiC particles and MgF2-quartz particles were characterized by a highly deformed, permanent surface crater with associated lateral and radial crack formation, and erosion loss was proportional to particle mass and velocity, both to the fourth power. Erosion of hot-pressed Si3N impacted with quartz particles was proportional to the third power of particle size and the first power of velocity, and loss occurred by minor chipping with no secondary crack formation. Erosion of glass-bonded A12O3 and reaction-bonded Si3N4 did not show a consistent particle size-velocity dependence. The variation is related to the two-phase structure of these materials. It was found that strength is not necessarily reduced for erosion conditions which produce appreciable material removal.

Ductile-brittle transitions and wear maps for the erosion and abrasion of brittle materials

“…For these reasons, marked differences are seen in the wear rates of ceramics eroded by different types of particle. Gulden (1979), for example, found the wear rate of hot-pressed silicon nitride eroded by silicon carbide particles to be approximately two orders of magnitude greater than that due to quartz particles under otherwise identical conditions. The erosion mechanisms were entirely different; the harder silicon carbide particles caused plastic indentation and lateral cracking in accordance with the elastic-plastic models, whereas the softer quartz particles caused minor chipping on a much finer scale than that of the particle contact area.…”

Determinación del Desgaste por Erosión en Materiales Recubiertos

“…. , , , se encuentran en la tabla 1, en la cual se resumen los resultados experimentales del rendimiento a la erosión de una variedad de recubrimientos cerámicos/partículas abrasivas para una temperatura cercana a 300 K. (Gulden, 1979;Wang, She y Ma 1995;Liebhard, 1994;Head y Harr 1994;Wiederhorn y Roberts 1976) Tabla 1: Combinaciones de recubrimiento cerámico y partícula abrasiva. (Khalil y Rosner 1996) (1979) El valor de n es especifico a la velocidad de la partícula y está normalizado por ≡ (ln )/ (ln ) y frecuentemente toma un valor de 2,3.…”

Micro-grooving on quartz crystals by an abrasive air jet

“…Finnie [27] studied the effect of spherical particles on brittle materials and reported that the velocity and impact angle of particles are the primary factors for the erosion of brittle materials, although he stated that to a different degree, particle size, shape, hardness, and strength are also important. Gulden [32,33] studied the effects of soft silica particles on silicon nitride. The author observed that no lateral fracture propagated due to impact and, therefore, suggested that the energy of the particle changed to the plastic deformation of the particles themselves and erosion was due to minor chipping.…”